HIV/AIDS; scientists all over the world collaborate (g) Irritability- enables plants to obtain nutrients like Sweep

Sweep net; used for

1. Describe the origin of the term biology in the fight against Ebola mineral salts, water etc.; enables animals to detect food catching flying insects
It is derived from two Greek words;  Through environmental conservation- the fight to and utilize it; facilitate mating in animals; enables the such as grasshoppers,
bios meaning life and logos meaning save the ozone layer through international organism to seek favorable conditions while avoiding bees, butterflies
knowledge agreements e.g. Kyoto protocol; management of unfavorable ones
2. Define the term biology resources through international treaties
(h) Reproduction- prevents extinction of a particular Fish net; used for
It refers to the scientific study of living organisms  Classification- scientists are using the same system trapping small fish and
species of organisms; increases the number of organisms
3. State what the following branches of biology deals of naming organisms that is binomial system other small water
of a particular species; enables a particular species of
with 5. Define the 7 characteristics each living organisms animals such as crabs,
organisms to be existent in one generation to another;
a) Botany- study of plants posses shrimps
3 main improves quality of species
b) Zoology-study of animals  Nutrition- it refers to the process by which living
c) Microbiology- study of microscopic organisms branches organisms acquire and utilize nutrients 8. Define the term stimuli- it refers to responses by
d) Mycology- study of fungi  Gaseous exchange- it refers to the process by organisms to changes in the environment(singular-
e) Biotechnology- involves development of techniques which respiratory gases (oxygen and carbon (IV) stimulus) Pair of forceps; used for
for application in biological processes Oxide) pass across respiratory surfaces along a picking up small
f) Ichthyology- study of fish concentration gradient 9. Define the term specimen- it refers to the body or a part
stinging animals such as
g) Entomology- study of insects  Respiration- it refers to the chemical breakdown of the body of a living organism being studied
centipedes, spiders,
h) Ornithology- study of birds of food in all living cells to yield energy, carbon 10. State 4 precautions to take while collecting specimen scorpion
i) Herpetology- study of snakes and reptiles (IV) Oxide, lactic acid, ethanol and water
j) Virology- study of virus Specimen bottles; used
 Excretion- it refers to the process by which living  Collect the number required number to avoid
k) Cytology- study of the cell for keeping collected
organisms separate and eliminate waste products wastage
l) Eurology- study of excretory organs specimen
of metabolism from their bodies  Do not destroy the habitat of the organism
m) Embryology- study of development  Growth and development- growth refers to the  Do not injure the organism because some parts
n) Physiology- study of body functions irreversible increase in the size and mass of the may be distorted
(o) Anatomy- study of internal structures of an organism body of a living organism; development refers to  Harmful specimens should be handles with care to
(p) Morphology- study of external structures of an the irreversible increase in complexity in the avoid being injured. use of a pair of forceps is 14. Study the diagram below and answer the questions that
organism structures of a living organism encouraged follow
(q) Genetics- study of inheritance and variations  Movement and locomotion- movement refers to  Live organisms after the study should be returned
(r) Taxonomy- study of grouping and sorting of the change in position of a part of an organism; to their habitat
organisms locomotion refers to the change in position of the  Highly mobile organisms should be immobilized
(s) Ecology- relation of an organism and their whole body of an organism using chemicals such as chloroform
surrounding  Irritability- it refers to the ability of an organism
to perceive changes in the environment and 11. Name 2 chemicals used to immobilize highly mobile
(t) Biochemistry- chemistry of materials in tissues respond accordingly organisms when collecting specimen

(u) Histology- structure of tissues  Reproduction- it refers to giving rise to a new  Chloroform (tetrachloromethane)
individual of the same kind  Diethylether (ethoxyethane) (a) Giving a reason name the apparatus above and state
(v) Phylogeny- study of evolutionary relationships 6. Differentiate between the following terms its function
between organisms (a) Growth and development 12. State 5 differences between plants and animals Hand lens/magnifying lens; it has a lens enclosed
(b) Movement and locomotion in a frame attached to a handle
(w) Bacteriology- study of bacteria *Refer to the answers from the previous Plants Animals
 Able to make their depend on readily made It is used to enlarge objects
(x) Phycology- study of algae questions (b) Name parts A, B, C
own food food
7. State the importance of the following characteristics of A- Frame
(y)Evolution- study of origin of organisms and their  Most have chlorophyll lack chlorophyll
living organisms B- Convex lens
progressive changes over a long period of time  have cellulose in cell Lack cellulose in cell
C- Handle
walls walls
4. State 4 importance of studying biology (a) Nutrition- it enables metabolic activities to take place (c) State 3 maintenance practice for this tool
 have limited Move freely
 Clean the lens using a soft tissue socked in ethanol
 Enable learners acquire skills useful in daily life (b) Gaseous exchange- it enables organisms to obtain movement
 Do not touch the lens with dirty fingers
 It is useful in solving environmental problems such oxygen necessary for respiration; carbon (IV) Oxide a  growth is only at the Growth is all over the
waste product eliminated  Avoid any chances of scratches on the lens
as pollution, poor health services, food shortage, meristematic tissues body
(d) Write the formula for calculation of magnification
environmental degradation (intercalary growth)
(c) Respiration- it yields energy useful in growth and using the tool above
 It enables us to understand the body functioning movement  do not have complex Have complex excretory
Image/drawing length
 It enables us acquire knowledge useful in pursuing excretory organs organs
Object/actual length
careers such as medicine (d) Excretion- facilitates elimination of waste products  respond slowly to Respond quickly to
 It enables us to acquire scientific skills such as which would otherwise accumulate and become toxic changes in the changes in the 15. Study the diagram below and answer the questions that
analyzing data hence causing harm to the organism’s health environment environment follow
 It enhances international co-operation as explained (e) Growth and development- Growth enables the
below organism to acquire maximum size and mass necessary 13. Name each of the following apparatus used in
4. Explain 3 ways in which biology enhances for proper body functioning and for defense; specimen collection and in each give examples of
international cooperation development readies the organism for reproduction organisms that may be collected using the specimen
 Through medicine- scientists from all over the
world have come together to develop a vaccine for (f) Movement and locomotion- helps an organism look for Apparatus Name; Function
food; look for mates; escape danger; look for shelter
 (b) Name 3 organisms which may be collected using the (a) Game warden- ecology  Facilitates conservation and management of
apparatus above- spider, ant, cockroach, millipede organisms since a specimen may be used
(c) State 2 roles of Y (b) P.E teacher- locomotion and movement repeatedly over a long period of time
 keeps rain out (c) Tour guide- ecology  Enhances detailed study of biological principles
 prevent collected organisms from escaping
(d) Name 2 precautions that should be taken into account (d) Fisheries biologist- ecology 29. State 4 methods of collecting insects’ specimen
when setting up the apparatus (e) Bee keeper- entomology  Sucking from barks of trees or rock surfaces
 Choose a site where rain water will not run into the  Physical picking using a pair of forceps
jar (f) Plant breeder- genetics, botany  Using a sweep net to catch flying insects
(a) Name the apparatus above and state its function –  The jar should be covered with a wood or a tile to  Trapping crawling insects using a pitfall trap
24. How do plants compensate for their inability to
pooter; used for sucking small animals from rock keep rain out and prevent collected organisms from
locomote
surfaces and tree barks escaping 30. Explain why it is important to preserve specimens
(b) Name 2 organisms which may be collected using (e) State 2 ways in which the efficiency of the above  They are autotrophic i.e. they manufacture their
setup can be improved  To enable reutilization of specimen to avoid
the tool above- ants, termites own food thus no need to locomote in search of
 By adding an immobilizing liquid so that the wastage
(c) Name Y and state 2 of its functions food
Mosquito net; it prevents dirt from entering the organisms does not move out  To reduce the frequency of disturbance of the
 Through tropic responses- by moving some parts
suction tube; it prevents the already collected  By camouflaging the apparatus i.e. covering with habitat of an organism
of they are able to respond to stimuli i.e. roots
organism from entering the suction tube ad vegetation growing towards water, light 31. Name 2 chemical reagents that can be used to preserve
subsequently into the mouth  Most are bisexual thus to facilitate self- specimen
18. Differentiate between the following terms
(d) State the role of X- Allows the organism to get fertilization hence reproduction
into the pooter (a). Autotrophic nutrition and heterotrophic nutrition-  Plants have the ability to absorb localized Formalin/formaldehyde/chloroform; alcohol
(e) Explain how collection of specimen using the tool autotrophic nutrition is a type of nutrition where living nutrients thus no need to move around 32. State one use of each of the following tools in biology
above works organisms manufacture their own food using simple  They have pollination mechanisms that ensures
The opening of tube X is put into cracks in rocks substances such as caron (IV) Oxide, water, mineral salts reproduction occurs without the need to move in a) Pair of forceps- used for picking harmful
or tree barks where the organisms are; the user and energy while heterotrophic nutrition is a type of search for mates organisms during specimen collection
then sucks in air through the opening of tube Z; nutrition where living organisms feed on already Used to hold specimen during
this creates a partial vacuum inside the jar and manufactured food 25. Name the characteristics of living organisms displayed dissection
air from the outside rushes into the jar to occupy by each of the following b) Pair of scissors- cutting animal tissues during
the vacuum; this forces the organisms into the jar (b) Partial/localized movement and locomotion/whole dissection
movement- partial/localized movement refers to change a) Cow drinking water- nutrition
through tube X c) Scalpel- cutting longitudinal and cross sections
in position of a part of an organism while b) Germinating maize grain- growth and
during dissection
16. Study the diagram below and answer the questions that locomotion/whole movement refers to change in position development
follow of the whole body of an organism c) Bacterial spore dividing- reproduction 33. Name 3 industrial processes that depend on the
d) Cheetah chasing after a gazelle- locomotion and knowledge of biology
(c) Sexual and asexual reproduction- Sexual reproduction movement
is a type of reproduction that involves gametes while e) Football fan watching a game and cheering-  Bread baking industries
asexual reproduction is a type of reproduction that does irritability  Brewing industries
not involve gametes f) Cow giving birth to a calf- reproduction  Manufacture of drugs in pharmaceutical
g) Vine climbing up a tree- movement industries
(d) Aerobic and anaerobic respiration – aerobic
h) Athlete panting at the end of a race- gaseous  Manufacture of milk products such as yoghurt
respiration is a type of respiration that occur in presence
exchange
of oxygen while anaerobic respiration is a type of 34 State 2 characteristics of living organism specific to
i) Mango tree producing juicy mangos-
respiration that occur in absence of oxygen plants- autotrophic nutrition; localized movement
(a) Name the apparatus above and state its use- Bait j) Seed producing heat during germination-
trap; it is used to attract and trap small animals 19. List 4 career opportunities in biology-dentistry, respiration 35. Name a branch of biology that deals with the study of
(b) Name 2 organisms which may be collected using medicine, agriculture, public health, horticulture, k) Bursting of a sporangium in the Rhizopus sp-
the apparatus above- rat, mouse pharmacy reproduction (a) Understanding the differences between plants and their
(c) Name X- bait l) A honey bee carrying pollen from one flower to offsprings- genetics
20. List 8 skills acquired while studying biology- another
17. Study the diagram below (b) Relationships between antelope and gazelle in their
Classifying, analyzing data, measuring, evaluating data, 26. Define a dissecting kit and state its use- it refers to a environment- ecology
recording data, observing, identification, drawing biological set which consists of apparatus used to cut
(CAMEROID) through an organism’s body or organ for the purpose of (c) Solving parentage disputes- genetics

21. Motor vehicles use energy and produce carbon (IV) anatomic studies; cut through an organism’s body or 36. Which scientist would suit your interest best if you are
Oxide and water. Similar characteristics occur in living organ for the purpose of anatomic studies interested in behaviour patterns in insects- ecologist
organisms yet motor vehicle are not classified as living. 27. List 4 tools found in a dissecting kit- scalpel, scissors, 37. Name any 4 international research centers conducting
List the other characteristics of living things that do NOT dissecting needle, safety pins, hand lens scalpel holder, biology related researches (institutions/organizations that
occur in motor vehicles Living things grow and develop, pair of forceps may provide employment to biologists)
reproduce, respond to stimuli(irritability)
28. Explain the necessity of specimen collection in biology  International livestock research institute (ILRI)
(a) Name the apparatus above and state its function 22. State the importance of irritability to plants- enables
plants to obtain essential products such as water and  To facilitate comparative studies of different  International centre for insect physiology and
Pitfall trap; it is used for catching crawling ecology (ICIPE)
animals mineral salts organisms from different environments
 It saves time during biological investigations in  Centre for disease control
23. What sort of biological knowledge would be useful to; the laboratory  Institute of primate research
38. State 2 differences between respiration and gaseous It manufactures its own food through photosynthesis by  J- hinge screw- used to incline the microscope Specimen under view can Specimen under view is
exchange combining water and carbon (IV) Oxide using light into a required shape be dead or alive dead
energy trapped by chlorophyll  K- Arm/limb- supports the stage and the body Specimen are stained using Specimen are stained using
 Respiration refers to the chemical breakdown of tube normal dyes complex stains
food in all living cells to yield energy, carbon (IV) 47. Define magnification- it refers to the ratio between the
 L- Base- provides firm and steady support Specimen is mounted on a Specimen is mounted in the
Oxide, lactic acid, ethanol and water while image length and object length
 M- Fine adjustment knob- raises and lowers the slide and placed on the grid and placed in a vacuum
gaseous exchange refers to the process by which stage in the open
48. State 2 potential risks that a biologist is exposed to body tube over short distances bringing the
respiratory gases (oxygen and carbon (IV) Oxide)
during collection of animal specimen image into a sharp focus 7. Name the building block of organisms- cells
pass across respiratory surfaces along a
 N- coarse adjustment knob- raises and lowers 8. Name the living substance in cells in which other
concentration gradient  Some of the animal specimen are stinging and the body tube over long distances bringing the organelles are suspended- cytoplasm
 Respiration is a chemical process while gaseous can cause potential harm 9. State 3 principles of the cell theory
image into a rough focus
exchange is a physical process  Some of the animals have viruses that can be (b) Give 2 reasons why the apparatus above should  The smallest unit of a living organism is the cell
39. Plants do not have complex excretory organs like transmitted to the biologist be handled with care  All living thigs are made up of one or more cells
animals. What could be the reason for this 49. Define the term biologist  It is expensive  All cells arise from preexisting cells by cell
 It is delicate division
 Plants produce less toxic waste compared to 50. Name the study of functioning of cells, tissues and (c) State 4 precautions to observe when using the 10. Explain why it is possible to see finer details using
animals organ apparatus above a light microscope other than a hand lens
 Plants reuse some of their wastes unlike animals  Always use both hands when carrying the This is because a light microscope has higher
 Plants deposits some of their wastes unlike apparatus above. One hand holding the base resolving power
animals TOPIC 3 11. Define the term field of view
and the other holding the arm
1. Define a cell It refers to the white patch of light observed
40. What is likely to happen if waste products are not It refers to the smallest basic and functional unit  Do not place the apparatus at the edges of
benches under the eye piece lens when light is
removed from bodies of living organisms of an organism
 Do not wet any part of the microscope to avoid concentrated on the stage of a light microscope
2. Study the diagram below of a light microscope 12. Explain why it is not advised to use the high-
They would accumulate and become toxic thus poisoning rusting of the metallic parts
cells  Make sure the low power objective lens click power objective lens together with the coarse
into position before and after use adjustment knob
41. Name 3 structures that may enable an organism to This is because the coarse adjustment knob may
(d) State 2 precautions to observe in order to care for
detect changes in the environment- eyes/ears/tongue/skin ram the objective lens against the prepared glass
the lenses of the apparatus above
42. State 2 ways in which growth differs in plants and  Do not touch the lens with your fingers to slide as it moves the body tube over long
animals avoid making them dirty or wet distances thus may cause damage to the Lense or
even crush the slide
 Dirty lenses should be cleaned using a special
 In plants growth only occurs at meristematic tissues 13. Where is the image projected onto when using an
lens tissue or tissue paper moistened with
while in animals’ growth occurs all over the body electron microscope
ethyl to avoid scratching
 In plants growth is indeterminate i.e. takes place Photographic film/fluorescent screen
3. What is the formula for calculating magnification
over a long unspecified period of time while in 14. Explain why an electron microscope has a high
using a light microscope\
animals’ growth is determinate i.e. takes place over resolving power than a light microscope
Magnification= Eye piece lens magnification x
a specified period of time An electron microscope uses beam of electrons
objective lens magnification
which have a shorter wavelength compared to the
43. what is sensitivity- it refers to the ability of an 4. State 3 advantages of a light microscope over an
light used by alight microscope
organism to detect changes in the environment and electron one
15. Explain why when using an electron microscope,
respond appropriately  A light microscope can be used to view both
the specimen under view must be dead
alive or dead specimen while an electron one’s
44. State 2 differences between plants and animals in terms This is because the specimen is placed in a
(a) Name and state the functions of the parts labelled only used to view dead specimen
of irritability vacuum
with letters  Electron microscope produces only white and 16. Explain why the specimen under view is placed in
 A- eye piece lens/ocular lens- it has lenses that black images while a light microscope produces
 Plants respond slowly to changes in the a vacuum when using an electron microscope
contribute to the magnification of the specimen coloured images
environment while animals respond quickly to To prevent the electrons from scattering
 B- body tube/burrel- it holds the ocular lens and  In a light microscope the image can be viewed 17. Explain why a light microscope produces clear
changes in the environment
the revolving nose piece directly while in an electron microscope a images limited to a magnification of 1000times
 Plants respond to changes in the environment
 C- Revolving nose piece/ turret- enables one to screen is required to view the image This is because above this magnification the
through tropic responses while animals respond
change from one objective lens to another 5. Define the term resolving power of a images loses clarity
to changes in the environment through
 D- objective lens- brings the image of the microscope/resolution 18. List the cell organelles observable when using a
locomotion
specimen to focus and magnifies it It refers to the ability of a microscope to light microscope
45. Highlight 4 processes in man which are dependent on  E- clip- it holds the prepared glass slide in distinguish between two close objects as separate Cell wall, cell membrane, cytoplasm, nucleus, sap
respiration position on the stage entities vacuole, tonoplast, chloroplast
 F- stage- is a platform where the slide 6. State 5 differences between a light microscope and 19. Name the suitable stain to be used when one wants
 Secretion of substances such as enzymes containing the specimen is placed an electron microscope to observe starch grains in a cell- iodine solution
 Transmission of nervous impulses  G- condenser- concentrates light on the Light microscope Electron microscope 20. Explain why the resolving power of a light
 Growth and development specimen on the stage Uses light for illumination Uses beam of electrons for microscope cannot be increase by increasing the
 Digestion  H- diaphragm- used to regulate the amount of illumination number of lenses at very high magnifications the
light going through the condenser Uses glass lenses for Uses electromagnetic lenses image produced losses its clarity
46. Explain how a bean will attain nutrition magnification for illumination
 I- Mirror- it collects light from the source and 21. Draw well labelled diagrams of the following cells
reflects it on the stage for specimen illumination Low resolving power High resolving power when observed under a light microscope
Low magnifying power High magnifying power (a) Animal cell
 (b) Plant cell  Traps light used in photosynthesis eukaryotes are organisms whose nucleus or 46. State 3 components of cell sap in vacuoles of
22. What are cell organelles  Stores pigment in plants(chlorophyll) nuclei are enclosed in a membrane plants
It refers to structures found within the cell (m) Vacuoles 32. Name 3 components of the nucleus Sugar, salts, waste products
Below are diagrams of plants and animal cells as i. Sap vacuole  Nucleolus 47. State 3 functions of sap vacuole in plants
seen under an electron microscope  Storage of cell sap for osmotic function  Chromosomes  Enables the plant cell to maintain optimum
23. State the functions of the following cell organelles  They create a turgor pressure contributing to  Nucleoplasm osmotic pressure
(a) Cell wall support especially in herbaceous plants 33. State 4 cell activities controlled by the nucleus  It maintains the shape of the plant cell
 Gives the cell its definite shape  Storage of food substances such as sugars and Respiration, protein synthesis, cell division, RNA  It contributes to support of the plant
 Protects the cell against mechanical damage mineral salts synthesis, DNA replication 48. Briefly describe the appearance of Golgi apparatus
 Allow entry and exit of substances in and  They store pigments that give various parts of 34. State the role of nuclear pores in eukaryotes They appear as stacks of flattened vesicles
out of the cell the plant their color e.g. petals Are channels of communication between the surrounded by a unit membrane with spherical
(b) Cell membrane  They may accumulate waste products and by nucleus and the cytoplasm vesicles at their ends which are pinched off from
 Selectively allow movement of substances products of metabolism thus providing a means Note the plural of nucleolus is nucleoli the flattened vesicles
in and out of the cell of excretion 35. Name the diffuse tangle of threads found in the 49. State the role of the spherical vesicles found at the
 Encloses the cell contents ii. Contractile vacuole nuclear sap of the nucleus- chromatin end of Golgi apparatus
(c) Cytoplasm  Osmoregulation 36. Name 2 components of the chromatin Facilitates exocytosis by transporting packaged
 Offers site for chemical reactions  excretion  Deoxyribonucleic acid (DNA) substances to the cell membrane fusing with it
 Carries other cell organelles and inclusions iii. Food vacuole  Some proteins then discharging its contents
(d) Nucleus 37. State 2 functions of the nucleolus Transports packaged substances such as proteins
 Storage of food
 It controls cell activities such as protein  Synthesis ribonucleic acid (RNA) and lipids within the cell
 Digestion of food
synthesis  Synthesis ribosomes 50. Name the most abundant cell organelle found in
(n) Ribosomes
 The nucleolus synthesize ribosomes 38. State the main difference between the inner glandular organs such as liver. Explain your
 Synthesis of proteins
 Nucleolus synthesis RNA membrane of a mitochondrion and that of the outer answer
(o) Pinocytic vesicle
The outer membrane is smooth while the inner Golgi apparatus. They are involved in the
 Carries genetic information in form of DNA  Enables the cell to obtain solid substances
membrane has infoldings called cristae processing and release of secretions
(e) Endoplasmic reticulum from the surrounding
(singular- crista) 51. With examples define the term secretion
 Transport substances such as lipids and 24. Name the 2 type of vacuoles in unicellular It refers to a substance made in a specific tissue
proteins within the cell organisms 39. In relation to mitochondria state 2 differences
between active cells such as muscle cells; or organ and taken to other tissues where it
(f) Rough ER  Contractile vacuole
spermatozoa and ess active cells such as fat cells perform fixations a specific function e.g.
 Transports proteins  Food vacuole Digestive enzymes manufactured in various
 Offers site for the attachment of ribosomes  Active cells have more mitochondria while less
25. Explain why cell membrane is also referred to as glands such as salivary glands which are then
(g) Smooth ER active cells have less mitochondria
bilayer released to the alimentary canal to digest food
 Synthesis lipids It consists of two protein layers sandwiched  Mitochondria of active cells have more cristae
while the mitochondria of less active cells have 52. Study the diagram below and state what it
 Transports lipids within the cell between two lipid layers represents
26. Describe the structure of the cell membrane less cristae
 Performs detoxification i.e. breakdown of It shows the process of formation of Golgi
40. State one adaptation of lysosomes (note that
foreign substances such as drugs  It consists of two protein molecules apparatus and the release of secretions by
lysosomes are dark and spherical)
 Synthesis steroids sandwiched between two lipid layers spherical vesicles through exocytosis
 The lipids occur in two layers with their  They have hydrolytic enzymes which destroy
(h) Golgi apparatus 53. Name 3 cells in plants that contain chloroplast
molecules facing away from each other worn out cell organelles and old cells
 Secretion of substances such as proteins, 41. Name the cell organelle which breaks down large
Palisade cells, spongy mesophyll cells, guard cells
hormones and enzymes  Some protein molecules occur in the inner 54. Describe the appearance of endoplasmic reticulum
molecules such as proteins, carbohydrates ad lipids
 Manufacture of glycoproteins through the and outer surfaces while others transverse the A system of parallel- flattened cavities and tubes
into simpler compounds- lysosome
modification of carbohydrates and proteins membrane lining forming pores through which are lined by a unit membrane
42. Explain how lysosomes destroy old or damaged
 Packaging and transport of cell secretions which substances pass 55. State 2 structural differences between the smooth
cells
 transport of substances out of the cell thus is Note that the membranes of other organelles ER and the rough ER
When a cell is old or damaged the membrane of
found close to the cell membrane such as mitochondria and the smooth ER share  Smooth ER has no ribosomes on its surface
lysosomes rapture releasing enzymes which then
 synthesis of lysosomes the xtic structure typical of the cell membrane while the rough ER has ribosomes on its
proceed to digest the contents of the cell
 facilitates processing of cisternae 27. Name the chemical compound which makes up the surface
43. Describe how a lysosome destroys a damaged
(i) mitochondria cell wall of plant cells- cellulose  Smooth ER is more tubular than the rough
mitochondrion
 Offers site for aerobic respiration 28. Name the chemical compound which enables cell ER
A membrane forms around the mitochondrion
(j) Lysosomes walls to serve a supportive function in some trees 56. State 5 differences between a plant cell and an
enclosing it in a vacuole
Lignin animal cell
 Supply enzymes that destroys worn out cell The lysosome fuses with the membrane and
29. Study the diagram below of a plant cell and its Plant cell Animal cell
organelles discharges digestive enzymes into the vacuole
adjacent cells and answer the questions that follow Has cell wall Lacks a cell wall
 Kills bacteria in white blood cells (a) Name part X and state its function
The enzymes then digest the mitochondrion
 Digest food materials in vacuoles releasing its building blocks into the cytoplasm Usually, large Often smaller
 Plasmodesmata (minute channels which Below are steps of how a lysosome destroys a Regular in shape Irregular in shape
(intracellular digestion)
transverse the adjacent walls of cells) worn-out cell organelle Has no centrioles Has centrioles
(k) Centrioles (rod shaped and found close to the
 They allow direct flow of substances between 44. Name the membrane that encloses a vacuole Some have chloroplasts Lacks chloroplast
nucleus)
neighboring cells Tonoplast Stores starch oil and proteins Stores glycogen and
 Forms spindle fibers that facilitates cell 30. Name the continuous motion exhibited by the
division by pulling chromosomes apart 45. Explain how a large central vacuole in a plant cell fats
cytoplasm- cytoplasmic streaming is formed when the plat is young the cells have Has a large central vacuole Has no vacuole but
 Forms cilia and flagella in organisms where 31. Differentiate between eukaryotes and prokaryotes
these structures occur smell vacuoles which as the plant matures, they when present is small
Prokaryotes are organisms whose nucleus or merge to form the large central vacuole and found within the
(l) Chloroplasts nuclei are not enclosed in a membrane while cytoplasm
Cytoplasm and nucleus are Cytoplasm and 64. State 2 roles of fixation
located towards the periphery nucleus occupy the  Makes the specimen stiff/hard
central position  It helps maintain the structure of the specimen
57. Distinguish between mounting and staining in 65. Explain the reason why plants specimen are
microscopy usually placed over a drop of water when
Mounting refers to the placing of a prepared slide preparing slides
on their stage of a microscope while staining The water ensures that the cells remain turgid
refers to process of applying dyes on the hence maintaining their shape (e) Sperm cell
specimen for clear observations 66. Explain why fixation is mainly done on animal
 It has a long tail-like extension for propulsion to
58. Distinguish between magnification and resolution specimen and not plants
reach the egg
of a microscope One of the roles of fixation is to make the seaman (b) Root hair cell
Magnification of a microscope refers to the  It has an acrosome that contain lytic enzymes
stiff. Plant materials are already naturally stiff  It has an extension called root hair which
ability of a microscope to enlarge tiny objects which digests the membrane of the ovum
67. Give 3 examples of fixatives used in the school provides a large surface area for absorption of
while resolution refers to the ability of a allowing the head to penetrate into the egg
laboratory water and mineral salts
microscope to distinguish between two close  It has numerous mitochondria which yields
 70% ethanol  It has a large sap vacuole to raise its osmotic
objects as separate entities energy for propulsion
 99% ethanol and 1% glacial pressure allowing absorption of water through
59. Explain the essence of the following during  It has a nucleus which carries the genetic
 Ethanoic acid osmosis
microscopy material of the parent
68. State 4 roles of a cover slip in microscopy  Are thin walled to reduce the distance of
(a) Staining  It holds the specimen in position and movement of water and mineral sats during
To enhance visibility of the cell organelles as the forms an even surface absorption
living cells are almost colorless and translucent  It prevents the microscope’s objective les  Has a thin flexible cell wall to facilitate
(b) Using a sharp razor blade from coming into contact with the penetration trough the soil particles
to allow making of thin sections specimen  Has a cell sap with dissolved sugars and salts to
to prevent distortion of the cell structure Note that 1 millimeter is equal to 1000 facilitate osmotic uptake of water from the soil
(c) Cutting thin sections micrometers (f) Red blood cell
To allow light to pass through  Thin cell wall to allow it to penetrate through the
I micrometer is equal to 1000 nanometer  Are bicon cave in shape to provide a large
(d) Moistening of the prepared section soil particles
69. Define the term cell specialization surface area for packing of hemoglobin
To prevent drying which would distort the cells It refers to the structural modification of newly  They lack a nucleus when mature to provide
Achieved by dipping the cut section in water formed cell in an organism in order to perform more room for packaging of hemoglobin
(e) Mounting specific functions  They contain haemoglobin which has a higher
To make it convenient and allow light to pass 70. With examples define the following terms affinity for oxygen enabling them to transport
through (a) Cell- it refers to the basic structural and oxygen
(f) Fixation functional unit of an organism e.g. palisade  Are pliable to be able to squeeze between blood
Usually involves passing the slide with the cell, red blood cell, nerve cell capillaries
preparation slowly under a mild flame (b) Tissue- it refers to a group of cells modified
To kill the living tissue and make the preparation to perform the same function e.g. epithelial,
permanent muscular, nervous and bone tissues in (c) Palisade cell
60. Explain why it is easier to make microscopic animals; phloem, xylem, palisade mesophyll  Have numerous chloroplast that contain
specimen of plants than of animals and epidermal tissues in plants chlorophyll to trap light for photosynthesis
This is because animal tissues are usually more (c) Organ- it refers to a group of tissues
delicate than those of plants  Are tightly packed to trap maximum light for
performing one or more functions e.g. photosynthesis
61. Differentiate between longitudinal sections and kidney, liver and heart in animals; leaves, (g) White blood cell
transverse sections stem, roots in plants  Have a large prominent nucleus which enables
Longitudinal sections are those cut along the (d) Organ system- it refers to several organs them to control cellular activities
length of an organism’s structure while coordinated to bring about an effective action  They exhibit amoeboid movement which enable
transverse sections are those cut across the in an organism e.g. circulatory, digestive, them to reach pathogens
structure of an organism respiratory and reproductive systems
62. List 4 common dyes used to stain specimens (e) Organism- it refers to a collection of organ
before viewing together with their colors systems
 Iodine solution- brown 71. Discuss the adaptations of the following
 Methylene blue- blue specialized cells
 Eosin- red/pinkish (a) Guard cell
 Fast green/ green  They have thick inner walls and thin outer
 Haematoxylene- purple/deep blue walls to allow differential expansion hence
63. Explain the difference between the 2 types of (d) Nerve cell
opening the stomata
mounts that can be used when preparing slides  Have extensions called axons and dendrites that
 They have chloroplast which enable them to (h) Muscle cell
Wet mounts are the most commonly used in transmits nervous impulses
photosynthesize  It has contractile fibrils which contract and
school laboratories where the specimen is placed  They are bean shaped and are two to create an relax bringing about movement
on a slide over a drop of water or any other liquid aperture hence stoma  It has numerous mitochondria to yield energy
while fixed mounts are those made to make the
for movement
specimen hard/stiff for sectioning and to
maintain the structure of the specimen by use of
chemical fixatives such as 70%ethanol
 helps to pump blood from the heart throughout  forms packing tissue in some plants filling It lines the internal surface of the alimentary,
the person’s life. Their cells have single spaces between other tissues respiratory, reproductive and urinary tracts. It is
nucleus and are joined end to end forming long  is partly responsible for maintaining the made up of simple epithelium
cylindrical muscle fibers shape of a plant 86. Name 2 parts of the human body where microvilli
 partly responsible for maintaining the are found and state their role
firmness in some plants Small intestine, kidney tubules
(i) Epidermal cells Increases the surface area for absorption
 They are transparent to allow light to reach the 87. Name 2 parts of the human body where cilia is
photosynthetic cells located
 Some lie guard cells have chloroplast for Respiratory epithelium (it propels mucus and
photosynthesis dust particles along it)
72. Name 2 type of cells found in the epidermal tissue 81. State the roles of the following types of muscles
88. State 2 adaptations of the connective tissue
in plants (a) Skeletal muscle
 Has strong fibers which enables it to connect
Epidermal cells, guard cells, root hair cells (in are responsible for locomotion and other
other tissues and organs
roots) voluntary movements.
 It has a matrix/ground substance in which
73. State the role of the epidermal tissue in plants (b) Smooth muscle
various types of cells and connective fibers are
Protect inner delicate tissues Their contraction helps in movement of (f) vascular bundle
materials along tubular structures such as embedded
74. Name the tissue in animals equivalent to epidermal  phloem translocate photosynthetic products 89. Name the ground substance in a connective tissue
tissue in plants- epithelial tissue the digestive tract  xylem translocate water and mineral slats Matrix
75. Epidermal cells in stems and leaves of plants are (c) Cardiac muscle
 xylem serves a supportive function 90. Name 2 cells in the human body that lack a
covered by a layer of wax. Name this layer and Their continuous contraction and relaxation
without fatigue helps to pump blood from the nucleus when mature
state its function- cuticle; it prevents excessive Red blood cell, platelet
loss of water through evaporation heart throughout the person’s life
91. Name the type of connective tissue in man that
76. Name 2 type of cells found in the photosynthetic 82. Explain the role of the following type of tissues in
an organism forms a rigid framework called skeleton
tissue of plants Skeleton tissue
Palisade cells, spongy mesophyll cells (a) Epithelial tissue
92. Name 2 kinds of skeletal tissue in animals
77. Name 2 locations of the nervous tissue in man  Is a thin continuous layer of cells that forms
Bone, cartilage
Brain, spinal cord, nerves the external covering of the body of an
93. State one adaption of the bone as a skeleton tissue
78. State 2 functions of dendrites in a nerve cell organism and various organs in the body (g) meristematic tissue in animals
 Connects the nerve cell to other nerve cells  It lines and protect internal surfaces of various  apical meristem brings about primary It has calcium salts which makes it very hard
 It facilitates transmission of nervous impulses tubular structures in the body of an organisms growth/increase in height/growth at the tips 94. Name the mineral element responsible for the
79. Define a muscle e.g. alimentary, respiratory, reproductive and of roots and shoots hardness of a bone- calcium
It refers to a contractile tissue responsible for urinary tracts  lateral meristem is responsible for secondary 95. State 2 adaptations of the parenchyma tissue
various kinds of movements in animals (b) Blood tissue growth/growth of the girth  Has cells with large sap vacuole for storage of
80. Explain the 3 different types of muscles in  Transports oxygen from the lungs to other
food
vertebrates body tissues (h) skeletal tissue  Has thin-walled cells to offer more room for
 Skeletal muscles- these muscles are attached to  Transports carbon IV oxide and waste  supports the animal off the ground packaging of food
bones and are responsible for locomotion and materials to various excretory organs  enables an animal to move 96. Name 2 parts in a plant where meristematic tissues
other voluntary movements. They are made up  Fight diseases causing germs  protects vital organs such as heart, brain and are found
of cylindrical cells (c) Connective tissue lungs Cambium of stems and roots, the tip of stems and
 Connects other tissues and organs holding (i) reproductive tissue roots
them in position responsible for the production of gametes, the 97. Define the term phagocytosis
 It fills spaces between organs sperms and ova It refers to the process of ingesting and digesting
83. state 3 different types of epithelial tissues a pathogen
columnar, cuboidal, squamous 98. Name 3 cell organelles present in plant cells but
84. Differentiate between simple epithelium and absent in animal cells
stratified epithelium Chloroplast, cell wall, large central vacuole
 Smooth muscles are found in the walls of the Simple epithelium consists of one layer of cells 99. A researcher was examining cells of an
digestive tract, respiratory tract, urinary tract, while stratified epithelium consists of two or unidentified animal organ under an electron
reproductive tract and the blood vessels. They more layers of cells microscope and found most cells rich in RER and
are made up of long, spindle-shaped cells with 85. Explain the following types of epithelial tissues in Golgi bodies. State the function of the organ.
a single nucleus. Their contraction helps in animals explain
movement of materials along these tubular (a) Epidermis Secretion of substances; Golgi apparatus produce
structures (d) Epidermal tissue It refers to the epithelial lining of the skin which secretions such as enzymes while RER transports
covers the whole body and protects it from them
 Protects inner delicate tissues from
mechanical damage, entry of pathogens and loss 100. Name the cell organelle that stores
mechanical damage
of moisture. It is made up of stratified epithelium enzymes
 It prevents excessive loss of water through
(b) Endodermis Lysosomes; Golgi apparatus
evaporation
It is the epithelium that lines the internal surface 101. The diagram below is a structure found in
 Protects inner tissues from infections
of blood and lymph vessels. It is made up of living organisms
 Cardiac muscles are the ones found in the (e) parenchyma tissue
simple epithelium (a) Name the parts labelled A, B and C
walls of the heart. Their continuous  offers storage site for food in most plants (c) Mucous membrane(mucosa) A- Protein layer; B- phosphate group; C-
contraction and relaxation without fatigue
lipid bilayer
102. In many microscopic preparations of (e) Focusing should never be done downwards with (a) Give a reason why nail varnish was smeared
animal tissues, it is difficult to make out cell the eye on the ocular Lense on the upper surface of the leaves
boundaries and yet the disposition and number of To avoid any chances of the objective lens To get the impression of the stomata
cells can usually be determined, which cell making contact with the glass slide as this (b) The impression was stained with methylene
structures make this possible would lead to damage of both the lense and the blue. Explain.
Nucleus slide To color the specimen and create contrast
103. Name the only cell organelle without a 113. A microscope had the following between various parts of the stomata hence
membrane- ribosomes specifications enhance visibility
104. All cell organelles appear to be Low power magnification= x100 (a) name the cell organelle above 125. Name the tissues that carry out the
membranous in nature (except ribosomes). What High power magnification=x500 Golgi apparatus (not Golgi bodies) following functions in mammals
could the significance of this common feature be? Under low power the field of view is 1500 (b) give 2 reasons for your answer in (a) above (a) Supports the animal's body off the ground. -
Membranes tend to provide large surface area for microns. calculate the field of vie under high  has flattened stacks of membrane bound Skeletal tissue
reactions in the organelles power of the microscope cisternae (b) Is responsible for movement. - muscular tissue
105. State 2 factors that determine the choice of (c) Transports oxygen throughout the body. - blood
 has spherical vesicles at its ends
microscope during biological investigations (c) name parts A, B, C tissue
 Size of the object to be viewed (d) Transmits impulses- nervous tissue
 A-Golgi body
 Degree of details required 126. The figure below is a diagram of a cell as
 B- Golgi vesicle
 Nature of the specimen seen under the light microscope.
 C- Golgi complex
106. Name the cell organelle that would be
120. Name the part of a plant cell that performs
abundant in goblet cells. Explain Which combination above would give a wider field of the following
Golgi apparatus. Goblet cells are involved in the view. Explain x100; the lower the magnification the (a) Synthesize glucose- chloroplast
secretion of substances and Golgi apparatus are greater the field of view (b) Secrete enzymes- Golgi body
incolved in secretion of substances 121. Give 3 examples of semi permeable
107. State 2 functions of nuclear membrane in 114. What name is given to a photograph taken membranes in cells
eukaryotes by an electron microscope Nuclear membrane, tonoplast, cell membrane
 Allow for communication between the Electron micrograph 122. State the role played by the following in
nucleus and the cytoplasm 115. State 2 differences between the following protein synthesis
 Encloses the contents of the nucleus (a) Mitochondrion and chloroplast
(a) Nucleus- releases ribosomal RNA used by the
108. State the structural modification of a (b) Smooth endoplasmic reticulum and rough ribosomes to synthesize proteins
Euglena cell endoplasmic reticulum (b) Ribosomes (a) Name the fluid found in the part labelled B and
 Flagella for locomotion (c) Ribosomes and lysosomes Offers site for proteins synthesis state its functions
 Eyespot for photosensitivity 123. State 3 adaptations of the mitochondrion  Cell sap
109. What might cell of the liver and glands to its functions  It stores salt and sugars
have in common  The inner membrane is greatly folded to form  It helps maintain an osmotic gradient for
They are all secretory cristae which offers a large surface area for osmoregulation
110. What would happen if an organism lost respiration  Helps to regulate the shape and turgidity of the
control of its lysosomes  Have organic matrix that provides a suitable cell
All its tissues would be destroyed due to excessive medium for respiratory reactions (b) Name the structure that contains most of the DNA
production of lysosomes which would lead to self-  Bound by 2 membranes to protect the inner  Nucleus
lysis delicate parts from external mechanical damage (c) Use the scale shown to determine the
111. If we could control lysosome activity at and to maintain the shape of the cell magnification
different tissues how could this help in the
 Has respiratory enzymes in the matrix to catalyze 1 cm on the diagram represents 5 micrometer on the
treatment of cancer respiratory reactions
This could be used in destruction of tumors 116. State 2 roles of ribosomes on the RER object
 Synthesis proteins  The membranes are semi permeable to allow for
112. Give a reason for each of the following Since 1 cm = 10000 micrometer magnification is x2000
 Release proteins into the RER selective entry and exit of materials into the
(a) A microscope should never be put to close to the
117. Explain how sap vacuole of plants matrix
edge of the working bench during practical 127. State 3 roles of parenchyma cells in a plant
contribute to support in herbaceous plants 124. In an experiment to determine the habitat
It could easily topple over and fall leading to  Storage of water
They vacuoles tend to absorb water by osmosis of two plants a leaf from each was obtained and
damages and breakages  Storage of food
and therefore swells, pushing the cytoplasm smeared with nail varnish on the upper surface and
(b) The microscope mirrors and lenses should never  Fills the spaces between tissues
against the cell wall. This makes plant cells left for 3-5 minutes to dry. The thin film of nail
be touched with the fingers  Some like chlorenchyma cells photosynthesize
turgid hence support varnish was peeled off with the leaf surface
 to avoid any scratches on the lenses impressions. The small part of the film from each 128. when examining cells from an unidentified
 to avoid any dirt on the Lenses which would 118. Give 2 reasons why the cell above is rabbit organ under an electron microscope you
palisade cell leaf was mounted on a microscope glass slide
lead to blurred images stained with methylene blue covered with a cover find that most of the cells are rich in Rough
(c) The microscope should never get wet at all costs  Has tightly packed abundant chloroplast endoplasmic reticulum and Golgi bodies. What
slip and observed under a light microscope at
To prevent metallic parts from rusting  It is cylindrical in shape does this tell about the organ
x100. The number of stomata within the field of
(d) When using the high-power objective lens, only 119. the diagram below represents a cell
view was counted and recorded and the results
the fine adjustment knob should be used for organelle It is a glandular organ involved in processing and release
tabulated as shown below
focusing of secretions
specimen No of stomata within
So that the objective lens can move the slightest the field of view 129. State 3 differences between cell membrane
distance preventing any chances of contact and and cell wall
B 80
hence breakages of the slide and objective lens
C 35
  Cell walls are thick, tough and rigid while cell  It enables it to attract materials to the cell  It facilitates exchange of materials between the
membranes are thin and delicate 9. Name 2 substances that are mother and fetus
 Cell walls consist mainly of cellulose while cell (a) Able to go through the cell membrane  It facilitates transmission of nervous
membranes consists mainly of lipids and proteins Water, vitamins, mineral salts, glucose transmission through the nervous system
 Cell walls are fully permeable while cell (b) Are too large to go through the cell membrane (b) Plants
membrane are partially permeable Starch, protein molecules  Absorption of mineral salts from the soil
130. state the role of cilia on epithelial tissues 10. Define the following terms  Gaseous exchange
(a) diffusion- it refers to the process by which  It contributes to the transportation of
Move materials over the epithelium particles move from a region of high photosynthetic products from the leaves to
131. Name 2 mammalian organs where the concentration to a region of low concentration their plant parts
epithelium has cilia along a concentration gradient  It facilitates removal of excess water from
(a) State and explain 2 observations made in the
(b) Osmosis- it refers to the movement of water plants through transpiration
 Trachea experiment
molecules from a dilute solution to a  Diffusion of fragrances produced by flowers to
 Oviduct  The contents in the visking tube turned blue
concentrated solution across a semipermeable attract pollinators
black while the contents in the beaker remained
membrane/it refers to the movement of water 19. Explain the importance of the flattened body of a
TOPIC 4: CELL PHYSIOLOGY brown
molecules from their region of high flatworm or leaves in plants
1. Defne the term cell physiology  This is because the wall of the visking tube is
concentration to a region of low concentration It provide a large surface area for diffusion
It refers to the study of cell functions semipermeable thus allowed small iodine
across a semipermeable membrane 20. Multicellular organisms have a small surface area to
2. Name 3 substances that the cell requires to perform molecules to move from the beaker where they
(c) Active transport-it refers to the movement of volume ratio thus diffusion occur slowly. Explain 2
its functions are highly concentrated into the visking tubing
molecules/ions from a region of low ways in which the problem of diffusion of materials
Water, glucose, amino acids, vitamins, mineral where they are lowly concentrated. The iodine
concentration to a region of high concentration has been resolved in these organisms
salts, gases (O2& CO2) the reacted with the starch to form a blue-black
against a concentration gradient by use of
3. What are physiological processes complex compound. On the other hand, the  The development of highly folded respiratory
energy
It refers to processes that involve movement of starch molecules are too large to move out of and absorptive surfaces over which diffusion
(d) Phagocytosis- it refers to the process by which
substances in and out of the cell the tubing thus the iodine in the beaker has to take place
specialized cells take in solid materials
4. Name 4 physiological processes remained brown  The body of some organs mat be flattened to
(e) Pinocytosis- it refers to the process by which
Diffusion, osmosis, active transport, pinocytosis, 16. State 4 factors affecting the rate of diffusion increase the surface area to volume ratio
specialized cells ingest vesicles containing
phagocytosis, exocytosis Diffusion gradient, temperatures, type of 21. State the main role of diffusion in living organisms
liquid which has dissolved substances
5. State 2 functions proteins in the cell membrane diffusing medium, size of diffusing molecules, Gaseous exchange
(f) Exocytosis – it refers to the process by which a
 Forms the pores through which substances cell releases secretory materials diffusion distance, surface area to volume ratio 22. Study the diagram below and answer the questions
enter or leave the cell 17. Explain how the following factors affect the rate of that follow
11. A potassium permanganate crystal was introduced to
 Some serves as carriers which transport the bottom of beaker containing water using a straw. diffusion
substances in and out of the cell State and explain the observations made (a) Concentration gradient
6. Study the diagram below of a cell membrane and After sometime a uniform purple solution was The greater the concentration gradient the faster the
answer the questions that follow observed. The crystal dissolved and its particles rate of diffusion and vice versa
spread from their region of high (b) Temperatures
concentration(crystal) to their region of low Increase in temperatures result in an increase in the
concentration(water) to form a uniform purple rate of diffusion as this increase the kinetic energy of
solution the diffusing particles hence, they move faster and
12. A student placed a perfume in one corner of the class vice versa
(c) Type of diffusing medium (a) State the main aim of the experiment
(a) Name parts labelled A, B, C and stood in the other corner. State and explain the To demonstrate osmosis using a visking tube
A- Phospholipid molecule observations made Gases diffuse faster compared to solids and liquids
because the particles in gases are far apart thus face (b) State and explain the observations made in the
B- Bilipid layer The perfume will smell at the other corner experiment
C- Pore because the perfume particles spread from their least resistance. On the other hand, solid particles are
closely packed with together thus experience the  Volume of the contents in the visking tube
D- Protein molecules region of high concertation to other parts of the increase and the viscin tube becomes firm
7. Explain 3 properties/characteristics of the cell room where they are lowly concentrated using maximum resistance
(d) Size of particles  Salt solution is hypertonic to the distilled
membrane kinetic energy
Smaller and lighter particles diffuse faster than water hence draws in water by osmosis
 Semipermeable- they selectively allow 13. Define the term concentration gradient swells and becomes firm
movement of substances in and out of the cell It refers to the difference in concentration larger and heavier particles
(e) Distance of diffusion 23. Explain why osmosis is a special type of diffusion
 Sensitive to pH and temperatures changes- between the region of high concentration and the Because it involves movement of water molecules
extreme pH conditions such as high basicity or region of low concentration Diffusion rate is slower when diffusion distance is
ling and faster when the diffusion distance is short from a region of high concentration to a region
acidity denatures the cell membrane. Moreover, 14. What is a visking tubing of low concentration across a semipermeable
high temperatures denatures the cell membrane It refers to an artificially made cell membrane (f) Surface area to volume ratio
Diffusion rate s faster when the surface area to membrane
as it is proteinous in nature which represents a cell membrane 24. Differentiate between osmotic pressure and osmotic
volume ratio is high and slower when the surface
 Polarized/possess electric charges- it has a net 15. Studt the diagram below and answer the questions potential
that follow area to volume ratio is great
positive charge on the outside and a net Osmotic pressure refers to the pressure exerted
18. State 4 roles of diffusion in
negative charge on the inside. The charges against a semipermeable membrane to stop
(a) Animals
enables it to attract materials into the cell and osmosis/water molecules from the dilute solution
also detect changes in the surrounding  It facilitates gaseous exchange across
respiratory surface entering the concentrated solution while osmotic
8. State 2 advantages of the cell membrane being potential refers to the hidden force of a
polarized  It facilitates absorption of digested food from
the gut concentrated solution which only becomes real
 It enables it to detect changes in the when the solution is separated from distilled
surrounding  It facilitates the elimination of waste from cells
water by a semipermeable membrane
 25. Name the instrument used to measure osmotic Water will flow from the solution into the  this increases the volume of the sap vacuole night there is little or no transpiration hence the
pressure- osmometer beaker a phenomenon called reverse osmosis which expands and pushes the cytoplasm and cells become deplasmolysed and become firm hence
26. Explain how the following changes when a plant cell 28. A sample of RBCs was placed in distilled water in a the cell membrane against the rigid cell wall he plant becomes firm
draws in water beaker. State and explain the observations made after  as more water is gained the sap vacuole exerts 40. At night plant cells become deplasmolysed after
(a) Osmotic pressure sometime turgor pressure on the cell wall and on the being being flaccid during the day making the plant
Osmotic pressure increase because the water A reddish color was observed in the distilled other hand the cell wall exerts an opposite and droop. Explain an instance in which a plant dies due
being drawn in dilutes the cell sap water after some time equal force (wall pressure) which prevents the to wilting
(b) Osmotic potential The red blood cells were hypertonic to the bursting of the plant cell If the water supply from the soil is insufficient the
It decreases because the water being drawn distilled water thus drew in water by osmosis and  when the plant cell is full/turgid wall pressure plant dies due to permanent wilting
in dilutes the cell sap (osmotic potentials became swollen and eventually burst as they lack is equal to turgor pressure 41. State 2 possible causes of wilting n plants
when dealing with water is also called water a rigid cell wall(hemolysis) 34. name one instance when wall pressure is equal to  If a plant loses more water than it gets from the
potential) 29. Explain what happens when a red blood cell is turgor pressure in a plant cell soil through transpiration
27. Study the diagram below and answer the questions placed in a a concentrated solution when the plant cell is turgid  if a plant is exposed to a concentrated salt
that follow The concentrated solution is hypertonic to the red 35. explain what happens when a plant cell is paced in a solution
blood cell thus the red blood cell loses water by concentrated solution 42. Study the set up below and answer the questions that
osmosis to the concentrated solution, shrinks and  the concentrated solution is hypertonic to the follow
reduces in size(crenation) plant cell thus water is drawn from the plant
30. Differentiate between hemolysis and cell into the concentrated solution through
crenation/laking osmosis
Haemolysis refers to the process by which an  this causes the cell membrane to shrink and
animal cell swells and burst after drawing in pull away from the cell wall as the volume of
water by osmosis when placed in a hypotonic the cell sap decreases
solution while crenation refers to the process by  the cell shrinks and is said to be
which an animal cell shrinks and reduces in size flaccid/plasmolyzed
when after losing water by osmosis when placed 36. name the condition responsible for holding leaves of
in a hypertonic solution plats in a horizontal position- turgidity
31. State one way in which the body ensures that 37. explain what is responsible for holding a tomato (a) State the aim of the experiment
crenation or haemolysis does not occur in cells plant erect To demonstrate osmosis in plant cells
A solution of sucrose/common salt and some Balancing of ions tomato plant is an herbaceous plant. It is remains (b) State the observations made in
methylene blue was added to the thistle funnel 32. Define each of the following terms erect as it is filled with fully turgid cells tightly i. Set up 1
whose opening at the base was covered with a 1. Turgor pressure packed together  Sugar crystals dissolves
sheet of a visking tubing. The solution of It refers to the pressure acting against the
 Level of water in the petri dish drops
sucrose/common salt was added slowly using a cytoplasm and the cell membrane of a plant cell
ii. Set up 2
teat pipette. It was then clamped as shown and when the plant cell draws in water after being
 No observable change
placed inside a beaker of water. placed in a hypotonic solution
iii. Set up 3
(a) State and explain the observations made 2. Wall pressure
 Sugar crystals do not dissolve
 The level of solution in the stem of the thistle It refers to an inward pressure equal to turgor
pressure exerted by the cell wall to prevent  Water level in the petri dish remains the same
funnel rises for some distance and then levels
bursting of the plant cell after drawing in water (c) Explain the observations made in
off
when place in a hypotonic solution i. Set up 1
 Water molecules moved from the beaker
3. Turgidity/turgor  The sugar crystals in the unboiled potato cube
where their concentration was high across the
It refers to the firmness of a plant cell after are moistened by the cell sap making a strong
semipermeable visking sheet into the thistle
drawing in water by osmosis wen place in a solution
funnel where their concentration was low. The
column of water in the stem of the thistle hypotonic solution  Water is extracted from the cells adjacent to the
funnel rose until pressure it exerted prevented 4. Plasmolysis cavity by osmosis.
further net uptake of water It refers to the process by which a plant cell loses  The cell saps of this cells become concentrated
(b) State one precaution to be observed during the water by osmosis and becomes flaccid after being and extract water from the inner cells
experiment placed in a hypertonic solution  The inner cells extract water from the cells at the
There should be no leakages at the base of 5. Flaccid/limp cell periphery of the potato cube which then become
the thistle funnel It refers to a plant cell whose cell membrane has concentrated and extract water from the distilled
(c) In relation to the experiment above define the shrunk away from the cell wall after losing water water in the petri dish
term hydrostatic pressure by osmosis when placed in a hypertonic solution ii. Set up 2
It refers to the height difference between the 6. Deplasmolysis  In the unboiled potato without sugar crystals
original level of solution in the stem and the It refers to the process by which a flaccid plant water does not get into the cavity since there is
final level cell gains water and becomes turgid after being no osmotic gradient between the cavity and the
(d) Explain what happens when placed in a hypotonic solution 38. Define wilting potato cells
i. Hydrostatic pressure is applied on the surface of 7. Incipient plasmolysis It refers to a condition in plants during dry weather in iii. Set up 3
the original solution column in the stem It refers to the point at which plasmolysis occurs which pants droop as a result of losing excess water by  In the boiled potato water does not get into the
This would prevent uptake of water from the 33. Explain what happens when a plant cell is placed in evapotranspiration making the cells flaccid cavity since the structure of the potato cells is
beaker distilled water 39. During the day plants droop. However, at night they destroyed and they are no longer able to carry
ii. Pressure higher than the hydrostatic pressure is  The distilled water is hypotonic to the plant cell become firm. Explain. During the day plants droop out osmosis
applied on the surface of the original solution thus the plant cell draws in water by osmosis as a result of losing excess water by 43. State the importance of osmosis in
column in the stem evapotranspiration making the cells flaccid. At (a) Microorganisms
 It facilitates uptake of water from the  glucose is required for energy production where  The material together with the surrounding  ·Reabsorption of water from kidney tubules.
surrounding medium to the cells of it is oxidized to yield energy from active transport membrane forms the phagocytic/food vacuole  ·Reabsorption of tissue fluid into the bloodstream
microorganisms  lack of glucose results in low energy production  The surrounding membrane cuts off g=from the at the venous side of the capillaries.
(b) Plants thus a slower rate of active transport and vice cell membrane and the vacuole migrates to the  ·Transpiration
 It facilitates absorption of water from the soil versa centre of the cytoplasm 59. Explain why:-(a) red blood cells burst when placed
 Transport of water from the epidermal cells of (c) temperatures  The vacuole fuses with one or more lysosomes in distilled water while plant cells remain intact.
the roots to the cells at the centre of the root  respiration is an enzyme-controlled reaction which discharge its digestive enzymes into it  The red blood cells take in water by osmosis.
 Movement of water from the veins of leaves which are affected by temperature changes  The soluble materials are absorbed into the They swell and exert pressure on the fragile
through the leave cells to the atmosphere  at optimum temperatures active transport is surrounding cytoplasm plasma membrane which then breaks.
through transpiration faster due to sufficient energy production  In Amoeba undigestible materials are egested by  Plant cells take in water and swell but do not
 Closing and opening of stomata resulting from optimum enzyme activity a reversal mechanism where the vacuole moves burst. This is because, their tough cell wall can
 It contributes to support by making the cells  temperatures below optimum inactivates to the surface and fuses with the cell membrane only stretch to a limited extent. Once fully
turgid in herbaceous plants and in non woody respiratory enzymes leading to low energy and discharges the undigestible materials to the stretched, the cell wall resists further expansion
parts of the plants lie leaves and flowers production hence a slower rate of active outside of the cell and no more water is taken up.
 Feeding in insectivorous plants transport 54. Explain how a cell benefits from pinocytosis 60. Addition of large amounts of salt to soil in which
(c) Animals  temperatures beyond optimum denatures Once the pinocytic vesicle is in the cytoplasm it plants are growing kills the plants. Explain.
 Reabsorption of water at the kidney tubules respiratory enzymes hence low rates of energy either raptures to release the dissolved substances
 Absorption of water at the intestines production thus a slower rate of active transport of these are released after being broken down to Plants normally grow in soils whose solute concentration
 Reabsorption of tissue fluid into the blood (d) enzyme inhibitors smaller molecules by digestive enzymes from is lower than that of the cell sap. This enables the plants
stream at the venous side of the capillaries  presence of enzyme inhibitors e.g. cyanide slows lysosomes to take up water by osmosis. Addition of large amounts of
44. State 2 similarities between diffusion and osmosis down the rate of active transport as it interferes 55. Describe a simple experiment to demonstrate salt to the soil plants lose water to the soil by osmosis.
 Both involves movement of molecules from a with respiratory enzymes in energy production diffusion of a solute Since water is very important for maintaining the
region of high concentration to a region of low and vice versa  Materials: A beaker of water and a crystal of structural and metabolic integrity of plants, its deficiency
concentration (e) power of hydrogen(pH) potassium permanganate. leads to death of the plants.
 Both are passive processes i.e. do not require  optimum pH conditions result in more energy  Procedure: Gently drop the permanganate crystal
energy production thus faster rates of active transport into the water. Leave the beaker undisturbed and 61. Name four processes in living things that depend on
 Both depend on a concentration gradient  extreme pH conditions such as high acidity or observe what happens. active transport.
45. State 2 differences between diffusion and osmosis alkalinity results in low rates of energy  Observation: The permanganate gradually  Absorption of soluble products of digestion, e.g.
 Diffusion involves movement of any type of production thus slower rates of active dissolves and the purple colour spreads until it is glucose and amino acids across the epithelial
molecules while osmosis involves movement of transport/stoppage uniformly distributed in the water. lining of the intestinal villi.
water molecules 50. state the roles of active transport in  Conclusion: Molecules of permanganate diffuse  Absorption of some mineral salts from the soil by
 Osmosis occurs across a semi permeable (a) plants from the crystal and spread throughout the water plant roots.
membrane while diffusion may occur in absence  Absorption of mineral salts from the soil forming a solution.
 Reabsorption of glucose, amino acids and
of semi permeable membrane  Translocation of photosynthetic products 56. With reference to cells distinguish between a freely
inorganic salts from the kidney tubules.
46. Iodine is in high concentration in sea weed than in from the leaves to other plant parts permeable structure and a semi-permeable structure
giving one example of each.  Pumping of sodium and potassium ions across
the soil. Name the process by which the sea weed (b) animals
 absorption of digested food from the  A freely permeable structure is one that allows the nerve cell membrane during the transmission
draws in the iodine
alimentary canal to the blood stream the free flow of molecules of different sizes across of an impulse.
Active transport
47. State and explain 2 factors affecting the rate of  excretion of waste products from cells it. An example is the plant cell wall. 62. In an experiment, equal volumes of blood were
osmosis  transmission of nerve impulses  A semi-permeable structure is one that allows incubated for one hour with different salt
certain molecules to flow across it but prevents concentrations. After the incubation, the number of
 Temperature- as temperature increase the rate of  reabsorption of sugar and salts in the kidney
others from doing so. An example is the plasma red blood cells in each setup was determined. The
osmosis increases as the water molecules gain tubules
more kinetic energy 51. name the process being described below membrane of all cells. results were as follows:
 Osmotic gradient- the higher the osmotic (a) white blood cell ingest pathogens such as 57. Define the following terms in relation to a cell
Final saltNumber of red blood cells after
gradient the faster the rate of diffusion and vice bacteria  (a) Isotonic solution Set up
 (b) Hypotonic solution concentration incubation
versa phagocytosis
48. State 4 factors affecting the rate of active transport (b) white blood cell feeds on microscopic organisms  (c) Hypertonic solution A 0.9% Normal
 Oxygen concentration such as plasmodium- pinocytosis  An isotonic solution is one whose solute
52. Give 3 roles of phagocytosis in living cells concentration is similar to that of the cell B 0.5% Fewer than normal
 Substrate concentration
 Enables WBCs to ingest and destroy pathogens contents.
 Temperatures
 Enables feeding in single celled organisms such  A hypotonic solution is one whose solute C 0.3% None
 Enzyme inhibitor concentration is lower than that of the cell
 pH as amoeba or protozoa  (a)Account for the results in setup: (i) A (ii) C
 Enables fertilization in some single celled contents.
49. explain how the following affects the rate of active  A hypertonic solution is one whose solute  (b) In what way would you expect the cells in
transport organisms setup B to differ from those in set up A?
concentration is higher than that of the cell
(a) oxygen concentration 53. Describe how a WBC or Amoeba carries out  (c)What observations would you expect to make
phagocytosis contents.
 oxygen is required for energy production where it 58. Name five processes in living things that depend on with regard to the number and shape of red blood
oxidizes glucose to yield energy for active  When a WBC or Amoeba comes into contact cells if the experiment was repeated with a salt
osmosis.
transport with the solid material e.g. food particle in the solution at a final concentration of 1.4%?
case of Amoeba or bacteria in the case of a  ·Uptake of water from the soil into the root hairs
 high oxygen concentration will result in more of plant roots.  (a) (i) 0.9% salt solution is isotonic to red blood
energy being produced hence a faster rate of WBC; it sends out fingerlike projections which cells.
surround the material.  ·Transport of water from the epidermal cells of
active transport and vice versa the root to the cells at the centre of the root.  (ii) 0.3 % salt solution is hypotonic to red blood
(b) substrate concentration cells. Water moves into the cells by osmosis
 causing them to swell and burst, a process called  Contains strengthening tissues which enables it 19. State the fate of the glucose manufactured during
haemolysis. to support the leaves (surrounded by tissues photosynthesis (4mks)
 (b) Cells in setup B would appear larger than such as parenchyma tissue, sclerenchyma tissue  Some is converted to sucrose and transported to
those in setup A. and collenchyma tissue which strengthen it) other parts of the plant
 (c)The number would be normal. However, the  Spreads the lamina enabling it to absorb light  Some is converted to starch and stored in the
cells would appear smaller in size and wrinkled efficiently leaf in form of starch granules
(crenated). (d) Intercellular air spaces  Some is used in respiration
Allow efficient diffusion of gases and water vapor 20. With an example state the fate of starch stored in the
between the leaf and the atmosphere leaf
TOPIC 5: NUTRITION 11. State 4 features/adaptations of the leaf epidermis It is reconverted back to glucose when need arises
1. Define nutrition  It is transparent to allow light to penetrate and e.g. at night when photosynthesis is not taking
It refers to the process by which organisms reach the photosynthetic cells place some is converted to glucose and used in
acquire and utilize nutrients  It has close fitting cells surrounding the whole formation of cellulose
2. State 4 importances of nutrition in organisms leaf 21. Study the diagram below showing the movement of
 Growth and development  It has stomata which facilitates gaseous chloroplasts in response to light intensity in palisade
 For energy production exchange mesophyll cells
 To fight diseases  It has guard cells which control the opening and
 Repair worn out body tissues closing of the stomata
3. Explain the difference between autotrophic and 12. State 4 adaptations of the cuticle
heterotrophic nutrition  It is transparent to allow light to penetrate and
autotrophic nutrition is a type of nutrition reach the photosynthetic cells
where living organisms manufacture their own Below is an internal structure of the leaf  It is impervious to water and gases thus prevents
food such as vitamins, proteins, carbohydrates excessive loss of water through evaporation
using simple substances such as caron (IV)  It is tough and therefore helps to protect the leas
Oxide, water, mineral salts and energy while from mechanical damage and entry of disease-
heterotrophic nutrition is a type of nutrition causing microorganisms (a) Explain the difference between the two
where living organisms feed on already  It is shiny and therefore reflects heat preventing 22. Name 2 parts of the plants where photosynthesis
manufactured food overheating of the leaf may occur
4. Explain the 2 different types of autotrophs and give 13. Name 2 mesophyll layers in a leaf Leaves, green parts of the stem
their examples  Spong mesophyll layer 23. State 3 importances of photosynthesis
 Photosynthetic organisms- they  Palisade mesophyll  It is the ultimate source of almost all organic
manufacture their own food using energy 14. State 4 adaptations of the palisade cells matter in nature. The organic compounds
from sunlight e.g. algae, green plants  They are closely packed for maximum manufactured by green plants are consumed by
 Chemosynthetrophs- they manufacture their absorption of light energy animas either directly or indirectly by feeding on
own food using energy from chemical  They have large number of chloroplasts from animals which have fed on the plants. Thus,
reactions/oxidation of inorganic compounds maximum absorption of light hence green plants are major sources of food in nature
e.g. non-green plants, some bacteria photosynthesis hence called producers
5. Give 2 examples of chemosynthetrophs 10. State 3 functions of the following parts of a leaf
 The chloroplast move within the cytoplasm  It is the only process that adds substantial
No-green plants, some bacteria (a) Epidermis
depending on the amount of light available amounts of oxygen to the atmosphere in the air
6. Define photosynthesis  Protects inner cells and tissues of the leaf from 15. Explain why chloroplasts in the cytoplasm of spongy which is used by other organisms in aerobic
It refers to the process by which plants mechanical damage palisade cells would be more on one side than the respiration
manufacture food using carbon IV oxide, water  Gives rise to the cuticle other  It utilizes carbon IV oxide thus helping maintain
and energy from sunlight  Allows light to penetrate to reach the During dim light they move to the upper parts of its normal concentration in the atmosphere
7. Explain how a mushroom manufactures its food photosynthetic cells the cell allowing maximum absorption of light 24. What are mesophytes
(refers to classification II)  Prevents the leaf from entry of disease-causing energy and in bright light they move to the lower These are plants which grow on well-watered soil
8. Name one by-product of photosynthesis organisms parts of the cell which protects them from 25. State the role of lamina in lives
oxygen (b) Cuticle bleaching effects of intense eight intensities Offers a large surface area for absorption of light
9. Write both a word and a chemical equation to  Protects inner cells and tissues of the leaf from 16. State 2 features of the spongy mesophyll layer energy and gaseous exchange
summarize the process of photosynthesis mechanical damage  It is composed of spherical/irregular shaped cells 26. State 3 functions of the guard cells
 Allows light to penetrate to reach the  The cells are loosely packed to create air spaces  Controls the opening and closing of the stomata
photosynthetic cells  Contain chloroplasts for photosynthesis  Controls gaseous exchange
 Prevents the leaf from entry of disease-causing 17. Explain why the lower parts of the leaf is usually  Controls the rate of water loss in a leaf
organisms light in color than the upper side 27. Study the diagram below ad answer the questions
 Waxy to prevent excess water loss from the leaf This is because palisade cells closer to the upper that follow
Below are external structures of a leaf
epidermis have more chloroplasts than the spongy
(c) Veins mesophyll cells closer to the lower epidermis
 Consists of xylem vessels which translocate 18. Name 3 tissues that strengthens the veins in the
water and mineral salts from the roots to the leaves of plants
leaves  Parenchyma tissue
 Consists of the phloem tissue which translocate  Collenchyma tissue
products of photosynthesis from the leaves to  Sclerenchyma tissue
other parts of the plants
 30. Explain how chloroplasts are adapted to their Some glucose is used in cell respiration; some To test for the presence of starch. A blue-black
functions converted to sucrose and transported toother parts of coloration would form showing the presence of
 Have chlorophyll pigment which traps light the plant and some converted to starch and stored in starch
energy used in photosynthesis the leaf in form of starch granules (e) State 2 possible control experiment for the above
 Has stroma where enzymes that speeds up 38. Name 3 products of the light stage of photosynthesis  Using a leaf from a non-green plants
photosynthesis are located Adenosine Triphosphate (ATP), hydrogen ions,  Using a leaf that has been in darkness for sometime
 Has granum for attachment of chlorophyll oxygen gas 45. Study the experiment setup below and answer the
 Has grana which forms the main site for light 39. State the fate of the following products of the light questions that follow
reactions stage
 They have stroma which provides the favorable (a) ATP
site for dark reactions  Used during the dark stage in carbon IV oxide
 Has starch grains for storage of starch fixation to combine carbon IV oxide and
 It is double membrane to ensure adequate hydrogen ions
protection of the inner delicate tissues (b) Hydrogen ions
(a) Name the cell organelles above and give a reason  Used in dark stage in carbon IV oxide fixation
for your answer  Has lipid globules for storage of lipids
31. Explain the term mosaic pattern/leaf mosaic and where it is combined with carbon IV oxide
Chloroplast; it is egg shaped; presence of grana (c) Oxygen gas
(b) State the role of the organelle above state its importance to plants
It refers to the leaf arrangement in most plants  Some is released into the atmosphere
Offers site for photosynthesis  Some is used in cell aerobic respiration
(c) State the importance of the organelle above in where there is minimum overlapping of the leaves;
this allows maximum absorption of light energy 40. Write both word and chemical equations to show the
taxonomy following processes
32. State 2 conditions for photosynthesis to occur (a) State the aim of the experiment
Used to distinguish some pans cells from all other (a) Photolysis
 Sunlight To determine the gas produced during
cells
 chlorophyll photosynthesis
(d) Name all the parts labelled with letters
33. State 2 requirement/ raw materials for (b) Why was a water plant used
A- Thylakoid disc
photosynthesis It can carry out photosynthesis under water using
B- Lamella (plural- lamellae)
 Water dissolved carbon IV oxide and at low light
C- Stroma
 Carbon IV oxide intensities
D- Lipid droplet (b) Carbon IV oxide fixation
34. Give 2 reasons why leaves of most plants appear (c) Why was sodium hydrogen carbonate added to the
E- Lamella (plural- lamellae)
green in color water
F- Granum (plural- grana)
It provides Carob V oxide necessary for
G- Starch grain  Presence of chlorophyll
photosynthesis by absorbing atmospheric carbon
H- Free ribosomes  Chlorophyll absorbs the blue and red
IV oxide
I- Outer membrane wavelengths and most of the yellow and green
(d) State the observations made
J- Inner membrane wavelengths are reflected
Production of air bubbles which collected at the top
K- Chloroplast envelope 35. Name the 2 stages of photosynthesis and name the
of the test tube
(e) Name the background material for the organelle part of chlorophyll where they occur 41. What is the importance of light stage in the process (e) Name the gas being produced- oxygen
above- stroma  Light stage/light dependent stage- granum of photosynthesis (f) State the role of the following in the setup
(f) Using letters name the part were  Dark stage/light independent stage- stroma Hydrogen ions and ATP is produced useful in the i. Wooden support
i. Oxygen is produced- A 36. Define the following terms dark stage during carbon IV oxide fixation Creates space between the funnel and the flow
ii. CO2 fixation takes place- C (a) Photolysis 42. List 4 products of light independent stage of of the beaker thus allowing free circulation of
iii. Enzymes that facilitate light reactions of It refers to the process by which light energy trapped photosynthesis water
photosynthesis are attached- F by chlorophyll is used to split a water molecule to form Glucose, water, fatty acids, amino acids ii. Funnel
iv. Enzymes used in the dark stage- C hydrogen atoms and oxygen gas 43. Explain why plants store food inform of starch and Directs the air bubbles into the glass tube
v. ATP is broken down to ADP and a (b) Carbon IV oxide fixation not glucose (g) State the likely identity of water plant X
phosphate molecule- C It refers to the process by which hydrogen atoms Glucose is soluble and osmotically active thus will Canadian pondweed; Elodea
28. What is the general shape of a chloroplast combine with carbon IV oxide forming simple interfere with the osmotic pressure of cells thereby 46. Study the experimental set up below and answer the
Biconvex shape sugars such as glucose affecting cell functions while starch is insoluble questions that follow
29. State the functions of the following part of the 37. Describe the following stages of photosynthesis and osmotically inactive thus will not interfere with
chloroplasts (a) Light stage the osmotic pressure of the cells thus efficient cell
(a) Grana Occurs in the grana in presence of sunlight functions
 Offers a large surface area for the attachment Chlorophyll traps light energy which is then used to 44. Explain why the following is done when testing for
of chlorophyll breakdown water molecules into hydrogen ions and starch in a leaf
 Offers a large surface area for the attachment oxygen gas in a process called photolysis (a) Using a leaf that has been exposed to light for 5
of enzymes required for the light reactions of The hydrogen ions are used in the dark stage during hours
photosynthesis carbon IV oxide fixation while the oxygen is released The leaf has photosynthesized thus starch is
(b) Starch grain into the atmosphere while some is used in respiration present
Storage of starch ATP is also produced in this stage (b) Dipping the leaf in boiling water
(c) Stroma (b) Dark stage To rapture the starch granules
 Has photosynthetic enzymes which speeds up Energy absorbed in light stage is stored in form of (c) Dipping the leaf in methylated spirit’
the rate of photosynthesis ATP which is then used in the dark stage (a) State the aim of the experiment
To decolorize it for clear observations to be made
Hydrogen ions from the light stage combine with To investigate if carbon IV oxide is necessary for
 Offers site for CO2 fixation (d) Spreading the leaf on a white tile and flooding its
carbon IV oxide to form glucose in a process called photosynthesis
(d) Lamellae surface with dilute iodine solution
carbon IV oxide fixation (b) In the setup above a destarched leaf is used. What
Joins the grana
is the meaning of destarching a leaf
 Removing starch from a leaf usually by placing 56. Explain how water affects photosynthesis indirectly
the plant in the dark or sometime Slight water deficiency in a plant leads to closure of
(c) If leaf B was tested for starch state and explain the the stomata thus preventing carbon IV oxide from
observations that would have been made getting into the plant
Brown iodine color persists 57. Explain how light wavelength affects photosynthesis
No starch produced since sodium hydroxide absorbed Chlorophyll absorbs mainly blue and red
caron IV oxide hence photosynthesis did not occur wavelengths and these are the ones used for
(d) Name one suitable control experiment photosynthesis. Therefore, the wavelength of light
Similar setup without sodium hydroxide falling on a plant will influence its rate of
(e) Explain what observations would have been made photosynthesis e.g.
if the flask had sodium hydrogen carbonate instead b) Light intensity In forests leaves on tall trees absorb most of the red
of sodium hydroxide The rate of photosynthesis increases with increase in and blue wavelengths and the light that filters
On addition of iodine a blue-black coloration (a) State the aim of the experiment light intensity. At higher light intensities the rate of through is of low intensity and in the green
would have formed. This is because sodium To investigate the effect of varying light intensity photosynthesis slowdown and levels off. At very high wavelengths. This reduces rate of photosynthesis in
hydrogen carbonate releases carbon IV oxide on the rate of photosynthesis light intensities chlorophyll is damaged and the rate plants growing in the forest floor thus only few
thus photosynthesis would have occurred (b) State the difference that would be observed if the of photosynthesis falls shade-tolerant plants are able to survive in forest
(f) Name an alternative substance that can be used setup is placed in sunlight and when placed in an floors
instead of sodium hydroxide open cupboard 58. Explain why only a few shade tolerant plants are
Potassium hydroxide; calcium hydroxide Many gas bubbles are released when the apparatus able to survive in forest floors
47. Study the experimental setup below and answer the is placed out in the sun the least number of bubbles Refer to answer above
questions that follow is produced when the setup is placed in an open 59. Explain the term compensation point in relation to
cupboard. This is because the rate of photosynthesis
photosynthesis is dependent on light intensity It refers to the light intensity at which the rate of
(c) State the how light intensity is varied in the setup carbon IV oxide production by a plant in
above respiration is equal to the rate of carbon IV oxide
By varying the distance between the light source consumption by the plant in photosynthesis and at
and the bulb this point all the sugar produced is used up in
(d) Explain the shape of the graph that would be respiration
obtained if the results are plotted of light intensity c) Temperature
versus the rate of photosynthesis determined by the The reactions of photosynthesis are driven by enzymes.
number of bubbles produced Enzymes work best in temperatures ranging from 35-
At low light intensities the light intensity is directly 40℃. At lower temperatures enzymes become inactive
proportional to the rate of photosynthesis. hence slows down the rate of photosynthesis. If the
However, the plot levels out at higher light temperatures goes beyond 40℃ the enzymes are
intensities as other factors become limiting denatured thus photosynthesis stops
(a) State the aim of the experiment (e) State the role of the thick glass
To investigate whether light is necessary for Helps to absorb heat from the lamp as heat also
photosynthesis influences the rate of photosynthesis
(b) State one precaution that should be carried out 49. What is a variegated leaf? It refers to a leaf with
before the beginning of the experiment some parts of its lamina lacking chlorophyll hence
Destarching the leaves by placing the plant in has different colors
darkness for 48 hours 50. How can we confirm that photosynthesis has  During daylight green plants carry out both
(c) State and explain the observations that would be occurred in a leaf photosynthesis and respiration. The relative rates of
made if leaf A is tested for starch By testing for starch both processes is greatly influenced by light intensity
The uncovered parts would turn blue black with 51. State 4 factors that affect the rate of photosynthesis  When light intensity is high photosynthesis proceeds
addition of iodine while the covered part would  Carbon IV oxide concentration
d) Water at a higher rate than respiration
remain brown on addition of iodine. This is  Light intensity
Plants with low amounts of water carry out  Under these conditions carbon IV oxide production
because the parts covered by the aluminium foil did  Temperature photosynthesis slowly while those with sufficient by respiration is lower than the rate at which it is
not receive light energy thus no photosynthesis  Water water supply carry out maximum photosynthesis if consumed by photosynthesis thus the plants must
occurred hence no starch is present while the 52. Explain how the following factors affect the rate of other factors are optimum take in carbon IV oxide from the atmosphere. In
uncovered parts received light thus photosynthesis photosynthesis 53. State the role of light in photosynthesis addition, sugar production exceeds the rate of sugar
occurred hence presence of starch a) Carbon IV oxide concentration It provides the energy required to drive the process utilization
(d) State the role of leaf B in the set up When carbon IV oxide concentration increases the
It serves as a control experiment of photosynthesis.  When light intensity is low respiration proceeds at a
rate of photosynthesis increases up to a certain level 54. Explain why photosynthesis will proceed faster on a higher rate than photosynthesis thus more carbon IV
(e) State the conclusion made at the end of the where it slows down and levels off because at this
experiment bright sunny day than on a cloudy day oxide is produced than it is being consumed and the
point other factors become limiting Due to higher light intensity on a sunny day than excess is released into the atmosphere.
Light is necessary for photosynthesis to occur
48. Study the experimental setup below and answer the on a cloudy day  Under this conditions the rate of sugar production is
questions that follow 55. State 3 qualities of light that affects the rate of lower than the rate of its utilization
photosynthesis 60. Explain why it is not safe to have potted plants in
 Light duration (how long) your room at night
 Light intensity(type) (Refer to the notes above)
 Light wavelength(strength) 61. State the law of limiting factor
 It states that a process influenced by several factors  They have a sweet taste (e) Most abundant in human blood- glucose  Are storage carbohydrates e.g. starch in plants
is governed by the factor that is in its lowest supply  They are crystalline in form 19. State 2 ways in which hydrolysis can be achieved  Are structural carbohydrates e.g. cellulose
62. Study the diagram below and answer the questions  They are reducing sugars e.g. they reduce  Boiling the solution in a dilute acid e.g.  When hydrated they form monosaccharides
that follow copper II ions to copper I ions hydrochloric acid (in the lab) which can be oxidized to yield energy
9. When glucose is added to Benedict’s solution and  By action of enzymes (in living systems)  Cellulose has commercial importance in
warmed for some time the color changes from blue to 20. Name the enzyme found in the small intestine that formation of cotton, paper and cello tape
orange. Explain hydrolyses sucrose to glucose and fructose 35. State 2 ways of hydrolyzing polysaccharides to
Glucose is a hexose sugar/monosaccharide Sucrase monosaccharides
thus is a reducing sugar. It reduces the blue 21. State 3 properties of disaccharides  Boiling them in presence of a dilute acid
soluble copper II sulphate present in Benedict’s  They are soluble in water  Through the action of enzymes
solution to copper I oxide which appears as an  They are crystalline in nature 36. Give 2 differences between monosaccharides and
orange precipitate  They have a sweet taste polysaccharides
10. State 2 functions of simple sugars  Lactose and maltose are reducing sugars Get them from properties
 They are oxidized to yield energy in while sucrose is a non-reducing sugar 37. State 2 differences between fats and oils
respiration 22. State 2 functions of disaccharides  Fats are found in animals while oil is found in
(a) Name the limiting factor between the following  They are building blocks of disaccharides  They can be hydrolyzed to monosaccharides plants
regions and polysaccharides
A- Light intensity
and oxidized to yield energy  Fats are solids at room temperature while oil is
11. Differentiate between condensation and hydrolysis  They are forms in which carbohydrates are liquid at room temperature
B- Temperature/ carbon IV oxide concentration Condensation refers to the process of
63. Explain why plants at their natural environment transported in plants 38. Name the building blocks of lipids
chemically combining two simple molecules to 23. State 2 reasons why carbohydrates in plants are Fatty acids, glycerol
rarely if ever photosynthesize at their maximum form a complex molecule with the product of a
potential transported in form of sucrose 39. State the main difference between carbohydrates and
water molecule while hydrolysis refers to the  Sucrose is soluble lipids
This is because at any one point one or more of the breakdown of a complex molecule to its
various factors of photosynthesis become limiting  Sucrose is inert Lipids have a lower concentration of oxygen per
constituent simple molecules in presence of 24. What is the general formula for polysaccharides molecule than carbohydrates
64. Explain how yields of plats in greenhouses are water
increased (C6H10O5) n where n is a large number resulting into 40. For each lipid molecule there is one glycerol
12. What is the general formula for disaccharides/double a large molecule molecule and 3 fatty acids hence called a
By increasing the rate of photosynthesis. This is sugars
through increasing factors such as carbon IV oxide 25. State 4 properties of polysaccharides ___________
C12H22O11  They are insoluble Triglyceride
concentration and temperature artificially by use of 13. Write an equation to show the formation of a
methane burners  They are not sweet 41. Give examples of fats and oils
disaccharide Fats-beef fat, butter fat, lamb fat
 They are not crystalline
Chemicals of life  They are non-reducing sugars Oil- corn oil, sunflower, groundnut oil
1. Define chemicals of life 26. State 2 differences between starch and glycogen 42. Name 2 chemical compounds that make up fats and
These are chemical compounds that make up  Starch is a storage carbohydrate in plants while oils- fatty acids, glycerol
bodies of living organisms 43. Give 3 examples of lipids in plants and animals
14. Name the bond that holds two monosaccharides glycogen is a storage carbohydrate in animals
Plants- phospholipids, oil
2. With examples differentiate between the two types of together  Starch appears in cells in form of grains while
chemical of life Animals- cholesterol, steroids, fats, wax
Glycosidic bond glycogen appears in form of granules
Organic compounds are those composed of 44. If glycerol is the same in all lipids explain why
15. Write equations to show the formation of the 27. Name 2 enzymes found in germinating seeds which
carbon in their structure e.g. carbohydrates, coconut oil is different from corn oil
following hydrolyses starch to glucose
proteins, lipids, vitamins and some hydrogen They consist of different types of fatty acids
(a) Sucrose Amylase/diastase; maltase
carbonates while inorganic are those that lack combined to the glycerol
(b) Lactose 28. State the role of enzyme diastase/amylase
carbon in their structure e.g. water, mineral 45. Name the bond between glycerol and fatty acid in
(c) Maltose Hydrolyses starch to maltose
salts, acids, bases, buffers and some hydrogen lipids
29. Name 2 parts of the alimentary canal where enzyme
carbonates Glyceride bond
amylase/diastase is found
3. State 2 main functions of carbohydrates 46. Write equations to show the formation of the
Mouth; duodenum
Storage of food following lipids
30. Name 3 plant products of economic importance
Production and storage of energy (a) Triglyceride
composed mainly of cellulose
4. State the ration of the components of carbohydrates Paper cotton, hemp
C:H:O=1:2:1 Write the process on the arrow 31. Name the polysaccharide described below
5. State the general formula of carbohydrates 16. Write an equation to show the hydrolysis of sucrose (a) Found in chloroplasts in form of granules- starch
(CH2O) n where n represents the number of (b) Stored in liver and muscles- glycogen
carbon atoms (c) Found in plant cell wall- cellulose
6. Give 3 examples of hexose sugars (d) Found in cell wall of some fungi and exoskeleton
 Glucose of arthropods- chitin
Write on the arrow the process and the enzyme. Do (b) Phospholipid
 Fructose 32. State 2 functions of cellulose in plant cell walls
also for the above
 Galactose  Plays a supportive role
17. Name 2 plants which stores their carbohydrates in
All have 6 carbon atoms per molecule. They  Plays a structural role
large quantities in form of sucrose
only differ in the arrangement of atoms in 33. State 4 functions of exoskeleton in arthropods
Sugar can, sugar beet
their structure
18. Name the carbohydrate found in  Gives the organism its shape
7. What is the general formula for monosaccharides  Protects inner tissues from mechanical damage 47. Study the diagram below and answer the questions
(a) Milk- lactose
(CH2O) n where n= 6  Protects the organism from desiccation that follow
(b) Germinating seeds- maltose
8. State 4 properties of hexose sugars  Gives the organism their shape
(c) Stem of a sugar cane- sucrose
 They are soluble in water (d) Stored in mammalian muscles- glycogen 34. State 4 functions of polysaccharides
 carbon, hydrogen, oxygen, nitrogen, sometimes They are amphoteric  Hormones- are proteins that regulate certain
Sulphur, sometimes phosphorus 65. State 4 functions of proteins metabolic processes in the body e.g. insulin
58. name the organic compound which is the most  They facilitate the growth and repair of cells which regulates the metabolism of sugar in the
abundant in the bodies of animals  They yield energy when oxidized mammalian body
proteins (makes of 50% of their dry weight)  they form respiratory pigments e.g. haemoglobin  Contractile proteins- are components of
59. show the structure of the following  they make antibodies which destroy disease contractile tissues e.g. myosin found in muscle
(a) State what the diagram above represents
(a) amino acids causing microorganisms fibers responsible for movement
Formation of a triglyceride
(b) Name A, B, & C  they form structural components e.g. in cell  Structural proteins- are important components
A- Glycerol membrane of various supportive tissues in the body such as
B- 3 fatty acids  they form enzymes which speed up (catalyze) the bone, cartilage and connective tissue.
C- Condensation metabolic processes Examples are collagen, keratin
48. State one function of phospholipids 66. name the proteinous respiratory pigment found in  Energy release- proteins can be used in
Forms a structural component in cell membranes of (b) glycine (a) Red blood cell respiration to provide energy but only under
cells (c) alanine Haemoglobin conditions of extreme starvation. Under these
49. State 3 properties of lipids (b) Muscles conditions tissue proteins are broken down
 Fats change to oil when temperatures are Myoglobin leading to emaciation
increased and vice versa 67. Define the following terms 75. Name the transport protein in man that transports
 Insoluble in water but soluble in organic solvents (a) Dipeptide iron to various parts of the body
 Lipids are inert thus are stored in tissues A combination of two amino acids Transferrin
50. State the main reason why lipids are stored in tissues (b) Pentapeptide 76. Give 2 examples of transport proteins in man
They are inert/unreactive A combination of five amino acids Haemoglobin, transferrin
51. State 4 functions of lipids (c) Polypeptide 77. Name the disease caused by the deficiency of
The R-group is called the side chain and is one that
A combination of many amino acids hormone insulin
 They are sources of energy. E.g. fats and oils are distinguishes one amino acid from another
(d) Tripeptide Diabetes Mellitus
oxidized to yield energy In glycine the side chain has one hydrogen atom and
A combination of three amino acids 78. Give 2 examples of contractile proteins and state
 They are sources of metabolic water when in alanine the side chain has a CH3 group
68. Name the bond between two amino acids their role
oxidized which can then supplement body water There are 20 naturally occurring amino acids in
Peptide bond Actin, myosin; they are found in muscle fiber and
requirements proteins and just like the letters of alphabets can be
69. Show a diagrammatic representation of formation of are responsible for movement
 They serve as shock absorbers thus protects vital used to make many words these amino acids can also
79. Give 3 examples of structural proteins
be used to make thousands of different kinds of a peptide bond
organs such as lungs, heart, kidney and behind Keratin, collagen, elastin
the eyeball proteins. Some contain all the 0 types while others
80. Highlight 2 methods through which proteins are
 They form structural components e.g. contain only some
hydrolyzed
phospholipids in cell membrane 60. name 3 components that plant use to manufacture
 Through heating in an acid
 They offer insulation against heat loss especially their amino acids
carbon IV oxide, water, mineral salts  Through the action of enzymes
in animals living in cold climates where they have 81. What are enzymes- these are proteinous substances
large quantities of fat (subcutaneous fat layer) 61. differentiate between essential and non-essential
amino acids that speed up biological reactions
under the skin 70. State what determines the biological activity of a 82. State 4 functions/roles of enzymes
 They facilitate buoyancy as they are less dense essential amino acids refers to those types of amino protein
acids manufactured by only plants and thus  Speeds up breakdown of food substances
than water hence floating in aquatic animals such The pattern in each protein molecule determined by chemically during digestion
as hippos, seals and whales which store a lot of fat animals obtain them through diet while non- bonds linking part of the molecule together
essential amino acids refers to those which can be  Catalyzes respiration
in their bodies 71. Explain why enzymes are denatured in temperatures
manufactured by animals and thus, they do not  Speeds formation formation photosynthetic
52. Explain why fats provide a convenient way in which of over 40℃.
obtain through diet products during photosynthesis
energy yielding molecules can be stored for use when This is because some bonds in the molecule are
need arises 62. With examples differentiate between first class and  Facilitates detoxification through the breakdown
broken at these temperatures leading to a change in
They are compact and insoluble second-class proteins of harmful substances to form harmless one
the structure of the proteins and thus loss of activity 83. Name one enzymes that performs detoxification
53. State the main function of oil in plants First class proteins refers to those that contain all 72. State 2 factors that can denature proteins
It is the main storage food in plant seeds the essential amino acids e.g. beef, milk, egg, beans Enzyme catalase
 Temperatures above 40℃ 84. Describe 2 methods of naming enzymes with
54. State the main advantage of fat to desert animals like while second class amino acids are those that lack
 Extreme pH conditions e.g. high alkalinity or examples
kangaroo rat and camel some essential amino acids e.g. maize, millet,
acidity  Trivial naming which involves adding the suffix
When oxidized the fats release metabolic water sorghum
73. Name the most abundant and important proteins in -in to the name of the person who first
which can then supplement body water Note that a good protein diet should contain one or
the human body discovered the enzyme e.g. ptyalin, pepsin
requirements more of the animal proteins or a mixture of plant
Enzymes
55. State 3 differences between lipids and proteins proteins  Naming enzymes according to the substrates
74. Name 4 groups of enzymes in the human body and
 Proteins have nitrogen in their structure while 63. State 4 properties of proteins they digest or the processes they catalyze e.g.
their functions
lipids do not  They dissolve in water forming colloidal lipase digests lipids and oxidase catalyze
 Enzymes- they catalyze biological reactions oxidation reactions
 Some proteins have Sulphur in their structure suspension(slippery)
 Transport proteins- they are found in blood  Group name e.g. proteases are groups of
while lipids do not  They are sensitive to high temperatures
where they bind and transport specific molecules enzymes which digest proteins
 lipids have a higher ratio of hydrogen to oxygen  They are amphoteric egg have both exhibit both
or ions from one part of the body to another e.g. 85. Differentiate between intracellular and extracellular
than proteins acidic and basic properties
haemoglobin enzymes and give examples in each
56. name the building blocks/basic structural units of  Are sensitive to extreme pH conditions
 Antibodies- they bind to and destroy disease Intracellular enzymes refers to enzymes which
proteins 64. Name the property of proteins that enables to form
causing microorganisms that invade the body catalyze reactions in cells in which they are
amino acids conjugated proteins (when they combine with non-
e.g. bacteria, viruses produced e.g. enzyme catalase, respiratory enzymes
57. name the structural elements in proteins proteins)
 while extracellular enzymes refers to enzymes
which catalyze reactions outside cells in which they
are produced e.g. lipase, maltase, rennin
86. State the roe of the following enzymes
(a) Ptyalin- digest starch in the mouth Explain why the reaction would proceed in the direction
(b) Pepsin- digests proteins in the stomach x and y
(c) Rennin- hydrolyses soluble milk protein If the substrates A and B are in high concentration the
caseinogen into insoluble casein reaction will proceed in the direction x which is towards
(d) Trypsin- digests proteins in the duodenum the formation of the products C and D. if the products C
(e) Lactase- digests lipids and D are in high concentration then the reaction will
(f) Urease- acts on urea proceed towards the direction y which is towards the
(g) Dehydrogenases- catalyze reactions which formation of substrates A and B (c) substrate concentration
involves removal of hydrogen from a substance 94. Define an active site/catalytic site increase in substrate concentration results in an
(h) Oxidases- catalysis oxidation reactions It refers to a precise place on the surface of an increase in enzyme reaction up to a certain point
(i) Reductase- catalyze reduction reactions enzyme to which the substrates molecules get where it slows down and levels off as all the active
87. State 4 properties of enzymes attached sites have been occupied. The leveling off can
 They are substrate specific e.g. each enzyme has a 95. Name the product formed when an enzyme and a reversed by increasing enzyme concentration
specific substrate that it acts on e, g, lipase only substrate molecule combine (d) enzyme concentration
acts on lipids Enzyme-product complex increase in enzyme concentration results in an
96. What are enzyme inhibitors increase in the rate of enzyme action up to a
 Enzymes are not affected by the reactions they
It refers to chemical substances capable of slowing certain point where at slows down and levels off
catalyze hence can be reused
down enzyme activity or completely stopping it Name the type of inhibition A and B as other factors become limiting
 Most reactions catalyzed by enzymes are reversible
97. Differentiate between competitive enzyme inhibitor A- Competitive inhibition (e) inhibitors
 They are proteinases in nature thus are affected presence of inhibitors slows down or completely
by extreme pH and high temperatures and non-competitive enzyme inhibitor B- Non-competitive inhibition
Competitive enzyme inhibitors are chemical 103. Name 4 factors affecting enzyme activity slops an enzyme catalyzed reaction as they occupy
 They are very efficient thus are required in small or alter the structure of the active site
quantities substances that compete for the active site of the Temperatures, pH/hydrogen ion concentration,
enzyme together with the substrate molecules thus substrate concentration, enzyme concentration, (f) enzyme cofactors
88. Explain how enzymes are affected by temperature presence of enzyme cofactors enhance enzyme
Temperatures above 40℃ denatures enzymes as slowing down enzyme activity while non-competitive inhibitors, product concentration
enzyme inhibitors refers to chemical substances that 104. Explain how the following factors affect enzyme activity thus increases the rate of the enzyme
they are proteinous in nature. This is irreversible. reaction
Enzymes work best in temperatures between 35- permanently combine with the enzymes hence activity
changing the structure of the active site of the (a) Temperatures (g) co-enzymes
40℃ while low temperatures inactivate enzymes presence of co-enzymes result in an increased rate
hence slows down their rate of reaction. However, enzyme  Enzymes work best at optimum temperatures i.e.
98. Explain how competitive inhibition can be reduced 35-40℃. At optimum temperatures there is of enzyme activity as they activate enzymes
this is reversible by reverting the temperatures to (h) product concentration
optimum range  Increasing substrate concentration increased enzyme activity due to increased
 Increasing enzyme concentration chances of contact between the enzyme and the increase in product concentration slows down the
89. A piece of liver of about 30g was dropped into a enzyme action rate because the product becomes
250ml beaker containing 50ml hydrogen peroxide. 99. Explain how competitive inhibition can be reduced if substrate. The rate of enzyme action doubles after
other factors remain constant every 10℃ increase. inhibitors
(a) State and explain the observations made 105. name the enzymes that work best in
A lot of fizzling and frothing is observed. This is due Increasing substrate concentration  At temperatures above 40℃ enzymes are
100. Give 3 examples of non-competitive inhibitors (a) acidic conditions
to the rapid production of oxygen gas as hydrogen denatured thus enzyme reaction falls and at 60℃
Mercury, lead, cyanide, silver, organophosphates pepsin, rennin
peroxide is broken down to water ad oxygen by the reaction stops as all enzymes have Benn
101. Explain why non-competitive inhibition cannot be (b) neutral conditions
enzyme catalase found in liver cells denatured.
decreased by increasing substrate concentration salivary amylase/diastase/ptyalin
(b) Write an equation for the reaction that occurs  At temperatures below 0℃ enzymes are
Non-competitive inhibition is permanent thus (c) alkaline conditions
inactivated therefore enzyme reaction decreases
cannot be decreased by increase the substrate trypsin, pancreatic amylase
concentration 106. with examples differentiate between enzyme
102. Below are diagrams showing the two cases of cofactors and coenzymes
90. Enzyme catalase is known to have the highest enzyme cofactors refers to non prtoeinous
enzyme inhibition
turnover number of all known enzymes. Explain components of the enzyme which enhance enzyme
what is meant by turnover number activity e.g. iron, magnesium, zinc, calcium,
It refers to the number of substrate molecules manganese while coenzymes refers to organic
converted to products per minute by a molecule of molecules from food substances such as vitamins
an enzyme which activate enzymes e.g. vitamin D, vitamin C
91. Name 2 parts of the human body where enzyme and nucleic acid
catalase is present 107. below is a graph showing the effect of substrate
Skeletal muscles, liver cells (b) pH/hydrogen ion concentration concentration on the rate of enzyme catalyzed
92. During a reaction an enzyme remains unchanged.  enzymes work best at optimum pH conditions reaction
Explain why new ones needs to be formed’  some enzymes work best in acidic conditions such
Enzymes are proteinous and they become as pepsin; some in neutral conditions such as
continually destroyed salivary amylase/diastase/ptyalin and some in
93. Reactions catalyzed by enzymes are easily reversible alkaline conditions such as trypsin
as shown below  extreme pH conditions denatures enzymes thus
decreased enzyme activity
 most intracellular catalyzed reactions occur at
neutral conditions
 116. State the role of the following we=hen testing for  Structural: Certain proteins, e.g. collagen, are color developed. A benedict’s test on the sample
non-reducing sugars important components of various supportive gave a clear blue solution. Another sample of the
(a) Hydrochloric acid tissues such as bone, cartilage and connective same food was made into a suspension with warm
Hydrolyses the non-reducing sugar into reducing tissue. water (about 35°℃). suspension. some millet seeds
sugar 125. List the important functions of water in living which had been soaked for 48 hours were crushed
(b) Sodium hydrogen carbonate organisms. and mixed with the suspension. The mixture was
Neutralizes excess hydrochloric acid  ·It is the solvent in which all biological reactions incubated in a warm water bath for 6 hours. After
117. Explain what happens during the emulsion test for take place. incubation, the sample gave a negative test with
lipids  ·It is a reactant in many biological reactions. iodine and a positive test with Benedict’s solution
(a) explain the shape of the graph between the  Lipids are soluble in ethanol but insoluble in photosynthesis. hydrolysis of food molecules such  (a) What does the dark blue colour developed on
following points water as carbohydrates, fats and proteins. addition of iodine indicate?
i. A and B  Water is miscible with ethanol  ·It is the solvent in which raw materials like  (b) What is a negative iodine test?
Increase in substrate concentration results in an  When ethanol with dissolved fats is mixed with mineral salts and finished products like sucrose  (c)Explain why the iodine test was negative after
increase in the reaction rate because active sites water it releases tiny fat droplets which then forms are transported in plants. the incubation.
of enzymes are available for the substrate the white emulsion  ·It helps in the maintenance of a constant body  (d)What is a positive Benedict's test and what does
molecules to bind 118. Describe an experiment used to test for the temperature in warm-blooded animals because of
ii. B and C it show?
presence of enzyme catalase in a food substance its high specific heat capacity.  (e) Why was it necessary to soak the millet seeds
The rate of the reaction slows down and levels off  Put 2ml of hydrogen peroxide in a test tube  ·It is responsible for the turgidity of plant cells first?
with increase in the substrate concentration  Drop the food substance into hydrogen peroxide and hence the maintenance of an erect posture.  (f)Suggest two control experiments for this
because all active sites have been occupied and observe  ·It is a habitat for many plants and animals. investigation.
108. What are prosthetic groups in relation to enzymes
 Effervescence confirms the presence of enzyme 126. Explain why enzymatic reaction rate increases
These are non-protein components of enzymes  (a) The dark-blue colour indicates the presence
catalase with increase in temperature
which enhance enzyme activity of starch.
119. Define emulsification
109. Explain how hydrolase enzyme slows down water As the temperature increases, the rate of the reaction also  (b) A yellow or brown coloration.
Breakdown of lipids into tiny droplets done by
re absorption increases. This happens because an increase in  (c) Because the starch had been hydrolyzed by
enzyme lipase
By increasing water use in hydrolysis temperature increases molecular movement thus amylase and maltase released by the activated
120. Give a reason why emulsification is important
110. What are vitamins increasing the chances of collision between the enzyme seeds.
 For easy absorption of lipids  (d) A positive Benedict’s test gives an orange
They refer to complex organic compounds required and substrate molecules.
in small quantities in bodies of plants and animals  Increase the surface area for enzyme action precipitate. It shows the presence of reducing
for proper health 121. Give any other substance that can be used instead 127. Differentiate between denaturation and sugars.
111. Explain how deficiency of vitamins in our bodies of ethanol in the laboratory inactivation of enzymes.  (e) The seeds had to be soaked to initiate the
results in diseases Sodium hydrogen carbonate solution germination process which mobilizes the
122. Explain how emulsification increase enzyme Denaturation is the destruction of an enzyme leading to a
Vitamins are coenzymes which activate enzymes enzymes.
action complete loss of enzymatic activity. It is brought about by
and thus their absence causes the enzymes to be  (f) Control experiments:
When lipids are broken down there is increased exposure to high temperature or extreme pH conditions.
inactive. Thus, metabolic processes breakdown Inactivation is temporary loss of enzymatic activity and is  ·A suspension of the food sample is incubated
resulting in deficiency diseases surface area of contact with the enzyme thus
brought about by exposure to low temperatures. with crushed seeds which had been killed by
112. Name one vitamin manufactured by animas and increased enzymes action boiling. In this case, hydrolysis of starch would
how it is manufactured 123. Amino acids are said to be the alphabet of not take place. This shows that the hydrolysis
128. What is the optimum temperature of an enzyme
Vitamin D; it is manufactured when the skin is proteins. If the letters A and B represent two different observed in the test samples is brought about by a
exposed to sunlight amino acids write down the sequence of all possible It is the temperature at which the reaction proceeds at the substance which is denatured by heat.
113. What are nucleic acids tripeptides that could be made from them maximum rate.  ·A suspension of the food sample is incubated
These are complex nitrogen containing organic AAA. AAB. ABA, ABB, BBB. BBA, BAB, BAA. 129. With reference to enzymes, explain what is meant with crushed seeds which had not been soaked.
compounds found in all living things by the "lock and key hypothesis”. In this case. digestion of starch would not take
114. Describe an experiment in which an enzyme is 124. What are the major functions of proteins in the place. This shows that the mobilization of
used to breakdown a non-reducing sugar to reducing mammalian body? Give at least one example in each Enzymes have a precise site on their surface called the enzymes require that the seeds be activated by the
 To a test tube place 3ml of starch solution case. active site or the catalytic site. It is here that substrate germination process.
 Add 1cm3 of amylase/diastase solution  Catalysis: Many proteins function as enzymes molecules bind. The shape of the active site and the 132. Three tubes each containing 1 ml. saliva and 1 ml.
 Warm the contents in a water bath whose catalyzing chemical reactions in the body, e.g. presence of various chemical groups ensures that only water were incubated in water baths at different
temperature is maintained at 35℃ for 6 minutes amylase which catalyzes the hydrolysis of starch. those substrates with a complimentary structure can bind temperatures as shown in the diagram below for 30
 Add benedicts solution and heat  Transport: Certain proteins which are found in to it. For this reason. only specific substrates or a group minutes. Another tube containing 1 ml. starch
 Color changes from blue to green to yellow and blood bind specific substances in one part of the of closely related substrates can bind to a particular and solution was incubated for the same length of time in
orange body and transport them to another part, e.g. open it, only specific substrates will fit into an enzyme's each water bath. The contents of the tubes in each
115. Describe a test that can be used to confirm haemoglobin which transports oxygen. active site. Once the substrate dissociates to release the water bath was then mixed and incubated for a
emulsification in lipids  Defense: Certain proteins called antibodies bind product and the enzyme. The free active site can bind further 30 minutes. The contents of each tube was
 Pour a little amount of cooking oil into test tube and destroy microorganisms that invade the body. other substrate molecules. then tested for starch using iodine solution.
labelled A and B  Regulation: Certain proteins act as hormones
130. Catalase has a turnover number of six million at 37
 Add 2cm3 of sodium hydrogen carbonate solution which help to regulate metabolic processes in the
°℃. Explain what this means.
to test tube A body.e.g. insulin which regulates carbohydrate
 Rinse the measuring cylinder metabolism. One molecule of catalase catalyzes the decomposition of
 Add 2cm3 of water into B  Movement: Certain proteins are able to contract six million molecules of hydrogen peroxide per minute.
and to relax and are involved in movement.
 Shake the contents in both test tubes thoroughly 131. A food sample was made into a suspension and a
Examples are actin and myosin which are found
and record your observations few drops of iodine was added into it. A blue-black
in muscles.
  (a)What was the aim of the experiment?
 (b)why was it necessary to incubate the tubes for 30 minutes before mixing the contents
 (c) State the colour changes you would expect to observe after adding iodine solution. (d) Account for the expected
observations.
 (d) Account for the observations made
 (a)To investigate the effect of temperature on the activity of salivary amylase.
 (b) To ensure that the contents of each tube attained the temperature of the water bath.
 (c) Tube A - Blue-black, Tube B- Brown. Tube C-Blue-black.
 (d) Tube A - no digestion of starch as the enzyme was inactivated by the low temperature.
 Tube B - digestion of starch took place as the incubation temperature was within the optimal range.
 Tube C -no digestion of starch as the enzyme was denatured by the high temperature.
133. In some plants, smearing the leaves with Vaseline on the lower surface will completely prevent photosynthesis. Suggest a
reason for this.
The leaves have stomata on the lower surface only. Therefore, smearing the lower surface with Vaseline completely blocks
entry of CO2 which prevents photosynthesis from taking place.  (a) What is the carbon dioxide concentration at (i) 3.00 a.m. (ii) 12.00 noon (iii) 4.00 p.m.?
 (b) Describe the pattern of carbon dioxide concentration as represented by the graph.
134. State the adaptations of the following parts of a leaf
 (c) Account for the carbon dioxide concentration between (i) 6.00 a.m. and 1.00 p.m. (ii) 6.00 p.m. And midnight.
(a) Epidermis
 (d) Give a word equation for the process that utilizes carbon dioxide in the forest.
(b) Spongy mesophyll
 (e) Besides light, name four other environmental factors that would affect the carbon dioxide concentration in the forest.
(c) Palisade mesophyll
 (f)What would happen if all the trees in the forest were cut down?
Adaptations of A:  (a)(i) 0.0425 (ii)0.0295
 (b) After midnight, the carbon dioxide concentration falls gradually until about 4.00 a.m. Thereafter, the concentration
 ·It is impervious to water and gases and therefore helps to reduce excessive loss of water by evaporation. falls rapidly reaching the minimum level at about 1.30 p.m. Then the concentration increases, gradually at first and
 ·It is tough and therefore helps to protect the leaf from mechanical damage and entry of disease-causing then rapidly reaching the maximum level at about midnight.
microorganisms.  (c) (i) As light intensity increases so does the rate of photosynthesis. This is accompanied by an increase in the uptake
 ·It is shiny and therefore reflects heat preventing overheating of the leaf. of carbon dioxide lowering its concentration in the surrounding air.
 ·It is transparent and therefore allows most of light to pass through.  (ii) During darkness photosynthesis ceases taking place but respiration continues. Respiration releases carbon dioxide
into the surrounding air resulting in an increase in its concentration.
Adaptations of I:  (d) Carbon dioxide +Water →Glucose + Oxygen
 ·Its cells are irregularly shaped and loosely attached thus creating large intercellular air spaces which allow efficient  (e) Temperature, Air currents (wind), Soil water, Humidity.
diffusion of gases and water vapour between the leaf and the atmosphere.  (f) Carbon dioxide level would remain constant at about the atmospheric level of 0.03% throughout the day.
 ·The walls of its cells are normally saturated with water, which allows transpiration to take place. 138. Why does leaving a plant in the dark for 48 hours result in destarching of the leaves?
 ·Its cells have chloroplasts, which enable them to carry out photosynthesis. Photosynthesis does not take place in the dark. However, respiration continues with glucose being broken down to carbon
Adaptations of J: dioxide and water. As glucose gets depleted, stored starch is hydrolyzed to glucose which is used in respiration or converted to
sucrose and transported to other parts of the plant. This eventually depletes the starch stored in the leaves.
 ·It has columnar cells, which enables many of them to be packed together for efficient absorption of light.
139. The diagram below shows the effect of varying light intensity on the exchange of carbon dioxide between the leaves of a
 ·The cells have a very large number of chloroplasts.
green plant and the atmosphere.
 of the cell allowing maximum absorption of light. In bright light they move to the lower parts of the cell which protects
them from the bleaching effects of intense light.
 ·Its cells are arranged on the upper surface of the leaf where they are exposed to abundant light.
135. When plants are exposed to very hot and dry weather, the rate of photosynthesis falls. Suggest an explanation for this.
The stomata close to reduce the rate of transpiration. This reduces the rate of CO2uptake and hence the rate of photosynthesis.
136. What is the role of water in photosynthesis?
To supply hydrogen atoms which are used to reduce carbon dioxide.
137. The carbon dioxide concentration in the air of a tropical forest was measured during the course of a 24-hour period from
midnight to midnight. The graph below shows the results of the measurements. Examine it carefully and answer the
following questions:

 (a) What is the name given to the point marked X?

 (b)With reference to carbon dioxide exchange state what happens at point X.
 (c) Explain how the effect observed at point X occurs.
 (d) Explain why there is a net uptake of carbon dioxide at light intensities above X.
 (e) What would happen to the plant if light intensity falling on it were maintained at X throughout?
  (f)What can you say about the exchange of oxygen between the plant and the surrounding air at light intensities below X? Proteins Put 2ml of the food substance into a A purple color forms Presence of proteins
 (a) Compensation point. clean test tube
 (b) There is no net uptake or release of carbon dioxide by the plant. Add an equal amount of 10% sodium
 (c) The rates of respiration and photosynthesis in the plant are equal. Therefore, all the carbon dioxide released by hydroxide solution and shake
respiration is used in photosynthesis. Into the mixture add 1% copper II Blue color of copper II Absence of proteins
 (d) At light intensities beyond X, the rate of photosynthesis is higher than the rate of respiration. This requires a net sulphate dropwise and shake after sulphate is retained
uptake of carbon dioxide. every addition
 (e) Growth would cease because all the products of photosynthesis would be utilized in respiration.
 (f) The plant will take up oxygen from the surrounding air since the rate of respiration is higher than the rate of
photosynthesis
Ascorbic acid To 2ml of dichloro indophenol Blue DCPIP is decolorized Vitamin C is present
FOOD TYPE PROCEDURE OBSERVATION INFERENCE/CONCLUSION (vitamin c) (DCPIP) in a test tube add an equal
Starch Add 2ml of the food substance into a Color change from brown Presence of starch amount of the sample solution and
clean test tube to blue-black DCPIP is not decolorized Vitamin C is absent
shake
Add 3 drops of iodine solution to the
food substance and shake
Observe the color change and record Brown color of iodine Absence of starch
your observations solution persists NUTRITION IN ANIMALS It refers to the physical and chemical breakdown of
large complex food molecules into smaller and simpler
1. Explain the 4 types of heterotrophic nutrition with molecules for easy absorption into the body
Reducing sugar Put 2ml of the food substance into a Color changes to green with Food substance contains a examples of organisms
clean test tube no further change on little amount of reducing (c) Absorption
 Holozoic nutrition- organisms feed on solid materials It refers to the uptake of soluble food materials from
Add an equal amount of Benedicts’ heating sugars obtained from plants and animals. it is carried out by
solution to the food substance and Color changes to yellow Food substance contains an the lumen of the digestive system through the lining of
mainly mammals, birds, reptiles, amphibians and in the gut and finally into the blood stream
shake average amount of reducing most invertebrates
Note the color of the mixture sugars (d) Assimilation
 Phagocytic nutrition- it is a type of nutrition were It refers to the incorporation of absorbed food
Heat the mixture in a water bath Color changes to orange or Food substance contains a organisms feed on solid food materials by individual substances into cell metabolism
Observe and record the color change brown high amount of reducing cells e.g. Amoeba (e) Egestion
sugars
 Saprophytic nutrition- organisms feed on dead or It refers to the removal of undigested food substances
Blue color of Benedict’s Absence of reducing sugars decaying matter e.g. fungi, bacteria
solution persists from the body
 Parasitic nutrition- an organism called a parasite 5. Study the diagram below of mammalian teeth and
Non reducing Put 2ml of the food substance into a Final color is yellow, Presence of reducing sugars obtains foods from the living tissues of another answer the questions that follow
sugar clean test tube orange or brown
organisms called the host and the host is usually (a) Name the parts labelled with letters
Add 4 drops of dilute hydrochloric harmed e.g. most fungi, bacteria, protozoa 6. Explain the following parts of the mammalian tooth in
acid to the food substance and shake
 Symbiotic nutrition/ mutualism- in this mode both terms of composition and function
Heat the mixture in a water bath for 3
organisms benefit but one organisms benefits with (a) Enamel
minutes
nutrients e.g. Rhizobium bacteria in roots of legumes  Composition- it is composed of calcium phosphate
Remove the test tube from the water
obtain nutrients and shelter while the plant benefits crystals bound together by keratin. It also has iron
bath
Final color is blue Absence of reducing sugars from nitrogen fixation carried out by the bacteria  Role- it forms an efficient hard biting and chewing
Add sodium hydrogen carbonate
2. Explain the following types of holozoic feeders and in surface. Prevents the dentine from wearing out
dropwise until fizzing stops
each give an example with use
Add Benedict’s solution whose
(a) Carnivores (b) Dentine
amount is equal to that of the food
They feed on flesh only e.g. lion, cheetah, leopard  Composition- it has a high mineral content. It has
substance
(b) Omnivores strands of the cytoplasm from the cells of the pulp
Heat the mixture in a water bath
They feed on both plants and flesh e.g. human running through it
Observe and record your observations
being, pigs, dogs  Role- has living cells which gives rise to the
Lipids Rub a little amount of the food Presence of a permanent Presence of lipids (c) Herbivores
(grease/translucent substance on a filter paper translucent spot enamel
They feed on plants only e.g. cow, giraffe, zebra (c) Pulp cavity
spot test) Hold the paper above a flame to dry 3. With examples differentiate between browsers and
Absence of a permanent Absence of lipids  Composition- has a soft connective tissue. It has
Hold the paper against light. Observe grazers
translucent spot blood vessels and nerve endings
what happens to the spot Browsers refers to herbivores that feed on trees and
Lipids (emulsion Put a little food substance into a test Formation of a white Presence of lipids and vice  Role- the blood vessels supply the tooth with
shrubs e.g. giraffe, gazelle while grazers refers to oxygen and nutrients and carries away waste
test) tube emulsion versa herbivores that feed on short plants e.g. cow, zebra,
Add 4cm3 ethanol to the food products. The nerve endings detect here, cold and
wildebeest pain
substance and shake thoroughly 4. Define the following processes of holozoic nutrition
Transfers the contents of the test tube (d) Cement
(a) Ingestion Role- fixes the tooth firmly to the jawbone
into another test tube half filled with It refers to the process of taking food into the body
water (e) Gum
through the mouth and swallowing it
Role- hold the tooth in place; prevents the tooth
(b) Digestion from bacteria entry
 (f) Periodontal membrane so that as the tooth wears out the sharp edge for  have jagged edges to crack bones to remove food particles which may encourage the
Composition- has connective tissues cutting vegetation is maintained 22. name 2 periodontal diseases in man growth of bacteria
Role- is a fibrous tissue which holds the tooth in the (b) canines are reduced or absent  dental caries/tooth decay (b) avoiding sugary food
jaw to create a space called diastema which offer room  periodontal disease reduce the bacterial action in the mouth
7. Name the hardest organic substance known for manipulation of food by the tongue by 23. describe the cause of tooth decay (c) addition of fluoride into water
Enamel separating the freshy cut vegetation and the bacteria in the mouth respire using sugars to control tooth decay
8. State 3 features of the enamel chewed vegetation producing acids which corrode the enamel and (d) see a dentist regularly
 It is the hardest organic substance (c) ridges of the upper teeth fit perfectly into grooves on may progress to the dentine if not treated early. so that small cavities or tooth decay can be detected
 It is non living the lower teeth Corrosion of the dentine may cause collapsing and treated early
 It is composed of keratin to allow for sideway grinding of vegetation hence exposure of the nerve endings thus heat, (e) eating tough fibrous foods
 It has calcium phosphate crystals and iron (d) the teeth have a wide opening into the pulp cavity cold and pain can then be detected to exercise teeth thus encouraging proper blood supply
9. State 3 features of the dentine (open roots) 24. state 2 possible solutions to tooth decay DIGESTION
 has a high mineral content (e) to ensure a continued supply of adequate food and removal of the tooth, root canal treatment 1. define the term digestion
 has living cells oxygen to the constantly wearing out tooth for its 25. explain how the root canal treatment works it refers to the chemical and mechanical
regrowth it involves destruction of the pulp cavity and filling breakdown of large complex food molecules into
 has strands of cytoplasm running through it
(f) most have a horny pad the space with artificial material smaller and simpler food molecules
 it is composed of collagen, calcium salts, and
to offer surface against which vegetation is pressed 26. state 2 possible causes of tooth decay 2. differentiate between intracellular and extracellular
water
and cut by the lower incisors  sugary foods digestion
10. name 2 substances that hardens the enamel
(g) have teeth with an open enamel  poor dental hygiene such as not brushing teeth intracellular digestion refers to the type of
calcium phosphate, keratin
to allow continuous growth to replace worn out after every meal digestion which takes place on cells while
11. dentine has a similar structure with the bone. Explain
surfaces to grinding  low levels of fluoride extracellular digestion refers to the type type of
why it is harder than the bone
16. explain the importance of grinding in herbivores 27. state the effect of very high fluoride content in drinking digestion which occur outside cells
it has a higher mineral content
it enables them to breakdown tough cellulose cell water 3. differentiate between mechanical and chemical
12. state the features and functions of the following types
walls which enhances the subsequent chemical it may cause browning of teeth (dental fluorosis) digestion
of teeth
digestion 28. explain how low fluoride content may cause tooth mechanical digestion is the physical breakdown if
(a) incisor
17. explain the reason for the following in carnivores decay food without its chemical nature being altered
 has one root
(a) have closely fitting incisors it results in weakening of the enamel thus while chemical digestion refers to the breakdown of
 is chisel-shaped to seize prey food by digestive enzymes thus the chemical nature
corrosion by bacterial acids
used for gripping food or cutting them into small (b) have long curved and pointed canines 29. state 4 signs of gingivitis/ periodontal disease of food is altered
pieces to pierce and tear flesh as well as for attack 4. state 3 functions of the mucus found in the walls of the
 bleeding gum
(c) have longitudinally ridged premolars and molars alimentary canal
(b) canine  sore gum
to increase the surface area for grinding  lubricates food for ease of movement down the
 has one root  swollen gum
(d) have some teeth modified into carnassial teeth gut
 long carnassial teeth  flabby gum
 prevents corrosion of the stomach walls by
 are cone-shaped for cutting flesh; crushing bones and slicing  reddened gum
hydrochloric acid
 it is sharp pointed meat  soft gum  prevents autodigestion by digestive enzymes
it is used for holding and piecing food (e) their teeth have closed roots with only a small 30. state the effect of gingivitis 5. state 2 sources of enzymes that carry out digestion
(c) premolar opening it results in destruction of periodontal membrane
 from glands in the digestive system e.g. from
to allow food and oxygen supply to the tooth to hence loosening of teeth and may eventually result
 has cusps/ridges on the surface to increase the gastric glands
keep the tooth alive in loss of teeth
surface area for chewing  from accessory glands e.g. liver
(f) jaws are connected to powerful muscles 31. state the main cause of periodontal disease. Explain
 has 2 roots 6. define accessory glands and give 3 examples
in order to move the jaws up and down by how it causes the disease named
chewing and grinding these are glands found outside the digestive system
snapping dental plaque; if the bacteria multiply due to food
(d) molar but secrete enzymes used in digestion e.g. liver
18. state 3 functions of carnassial teeth in carnivore particles if sugary foods in diet they invade the
 has 3 roots gums and eventually the periodontal membrane
pancreases, salivary glands
 has ridges/cusps  cutting flesh 7. define mastication and give 2 of its roles
 crush bones 32. what is dental plaque
chewing and grinding it refers to the physical breakdown of food by
it refers to a soft invisible layer of bacteria which
13. differentiate between dental formula and dentition  shearing flesh/skin/tendons action of teeth
forms on teeth and is present in all mouths
dental formula refers to the number and  serve as a pair of shears for slicing flesh it increases the S.A for enzyme action
33. state 4 general method of preventing tooth diseases
positioning of different types of te4eech in the jaws 19. state 2 adaptations of carnassial teeth in carnivores it makes food easy to swallow
 dental hygiene e.g. brushing teeth after every
of an animal while dentition refers to shape and  have sharp edges for slicing flesh 8. state the role of the tongue in digestion
meal
specialization of teeth in an animal  has blades which overlap hence shearing it manipulates food by mixing it with saliva
 less sugary foods to reduce bacterial action in
14. write the dental formula for the following animals  are enlarged for crushing bones 9. state 2 roles of saliva in digestion
the mouth
(a) human being 20. give the advantage of chewing food before swallowing  provides suitable neutral or slightly alkaline
 taking oral antibiotics to reduce bacterial load in
(b) dog  for easy swallowing medium for enzyme action
the mouth
(c) sheep  to increase the surface area for enzyme action  contains water that softens food
(d) goat  visit a dentist regularly for dental checkup
21. give one modification of premolars and molars to their  contains enzyme ptyalin which breakdown starch
15. give reasons for the following in herbivores 34. explain how the following prevent teeth diseases
function in carnivores to maltose
(a) enamel coating is thicker at the front than at the back (a) regular brushing of teeth
 have cusps to increase the surface area for  lubricates food for easy swallowing
chewing 10. name 2 digestive enzymes found in the mouth
 ptyalin/diastase/salivary amylase, lysozyme, lingual 24. state 4 roles of hydrochloric acid present in the  makes the contents of the duodenum slightly (c) Lactase
lipase stomach alkaline thus optimum pH conditions for the Breaksdwon lactose to glucose and galactose
11. name the types of salivary glands and their location  activates pepsinogen to pepsin action of pancreatic and intestinal enzymes (d) Peptidase
 parotid gland- found in the cheeks infront of the  kills bacteria present in food (g) nucleases Breaksdown peptides to amino acids
ears  begins hydrolysis of sucrose  breaks down RNA and DNA into nucleotides (e) Pancreatic lipase
 sub-mandibular gland- found under the jaw  provides suitable pH conditions of 1.5-2.5 for 32. name were enzyme enterokinase is produced and state Breaks down lipids to glycerol and fatty acids
 sublingual gland- found beneath the tongue action of enzyme pepsin its functions (f) Nucleotidase
12. define the term peristalsis  breaks down nucleotides into nucleoproteins and it is secreted by the cells of the duodenal walls; they Breaks down nucleotides into their constituents
it refers to the involuntary propulsion of food down nucleic acids activate trypsinogen to trypsin (g) Polypeptidase
the gut due to the rhythmic contraction and  denatures proteins and softens fibrous 33. state the role of bile salts in digestion Breaskdown polypeptides into peptides
relaxation of the longitudinal and circular muscles connective tissues in food breaks down large fat droplets into small droplets; 49. Name 3 constitutes of nucleotides
found in the walls of the gut 25. describe the cause the heartburn emulsification Pentose sugar, nitrogen base, phosphoric acid
13. name the muscular valve through which food enters the after a heavy meal pressure in the stomach builds 34. name the excretory product of the breakdown of 50. Define chyle
stomach- up and causes some HCl to leak into the esophagus haemoglobin It refers to the resulting water emulsion after
cardiac sphincter and since the oesophagus has no mucus lining the bilirubin digestion in the ileum consisting of soluble end
14. define churning HCl causes a burning effect producing pain hence 35. state what may cause absence of bile in the duodenum products of digestion ready to be absorbed
it refers to the mixing of the food together with the heartburn and its effect 51. Define the term absorption
contents in the stomach by contraction and 26. explain why food does not enter the ileum directly blockage of the bile duct; this will result in very 52. Name 4 substances that are absorbed in the stomach
relaxation of circular and longitunal muscle layers while in the stomach little digestion of lipids and most of them will be Some water, medicine, alcohol, vitamins
in the stomach walls forming chyme due to the presence of a muscle valve called pyloric voided in faeces 53. Name 2 fat soluble vitamins
15. define chyme sphincter which closes the entry into the duodenum 36. name 2 nucleases present in the pancreatic juice Vitamin A, D, E, K
it refers to the porridge-like mixture... 27. name the muscular valve in which food enters the ribonuclease, deoxyribonuclease 54. Name 2 water soluble vitamins
16. describe the effect of arrival of food in the stomach duodenum 37. name 2 contents of the bile Vitamin B, C
arrival of food in the stomach stimulates hormone pyloric sphincter bilirubin, bile salts 55. State the role of bile in digestion
gastrin which then stimulates gastric glands which 28. state 2 effects of entry of food into the duodenum 38. name 2 bile salts Enhances absorption of fat-soluble vitamins
then release gastric juice into the stomach sodium taurocholate, sodium glycocholates 56. Define defaecation
 it stimulates hormone secretin which then
17. name 4 contents of the gastric juice stimulates the pancreas to release pancreatic 39. state 3 functions of bile It refers to the process by which rectum muscles
hydrochloric acid, pepsinogen, rennin, mucus  neutralize acidic chyme from the stomach contract pushing out indigestible food substances out
juice into the duodenum and the gall blader to
18. name the cells which secrete the following  provides suitable alkaline medium... through the anus
release bile through the bile duct
(a) hydrochloric acid  carries out emulsification of lipids thus enhances 57. State the role of the bacteria and protozoa present in
 it stimulates hormone cholecystokinin which
parietal cells lipids digestion the large intestine
stimulates the liver to secrete bile and the
(b) rennin 40. state 2 roles of the Brunner’s glands They feed on undigested food materials
pancreas to release sodium hydrogen carbonate
peptic/chief cells  Secrete an alkaline fluid which neutralize acidic 58. State the effects of the bacteria and protozoa present in
29. where is hormones cholecystokinin and secretin
(c) mucus chyme and provides suitable alkaline... the large intestine
secreted
goblet cells  Secretes mucus which lubricates duodenal walls Results in the synthesis of vitamins such as vitamin K
duodenal walls
(d) pepsinogen for easy peristalsis Leads to formation of gases like carbon IV oxide,
30. list 5 contents of the pancreatic juice
peptic/chief cells methane and hydrogen sulphide
pancreatic amylase, pancreatic lipase, trypsinogen, 41. Name the enzymes that complete the process of
19. state the functional difference between rennin and 59. Name 2 vitamins synthesized by microorganisms in the
chymotrypsin, carboxypeptidase, sodium hydrogen digestion
pepsin large intestine
carbonate, nucleases Intestinal enzymes
rennin performs coagulation of milk while pepsin Vitamin K, B12
31. state the functions of the following contents of the 42. Name 2 parts of the gut where crypts of Lieberkühn are
breaks down proteins to peptides 60. State the fate of glucose that is carried to the liver
pancreatic juice found
20. write an equation to show pepsins action on proteins Duodenum, ileum  It is respired
(a) pancreatic lipase
hydrolysis 43. Name the glands that secrete intestinal juice (succus  It is converted to glycogen and stored
 breaks down lipids into fatty acids and glycerol in
proteins peptides presence of bile salts entericus) 61. State the use of absorbed amino acids in the body
pepsin (b) pancreatic amylase Crypts of Lieberkühn glands They are used by the body cells to form proteins
21. give a reason why pepsin is secreted in its inactive 44. State the effect of arrival of chyme in the ileum 62. What happens to excess amino acids in the body
 breaks down starch which was not broken down in
form Stimulates the secretion of intestinal juice They are deaminated
the mouth into maltose
to prevent digestion of the proteins, present in cells 45. Name the enzymes present in intestinal juice 63. What happens to the residual compound after
(c) trypsin
in which they are produced i.e. autodigestion Maltase, lactase sucrase, peptidase, polypeptidase, deamination
 activates chymotrypsinogen into chymotrypsin It is converted to glucose and respired
22. what is coagulation and state 2 of its importances pancreatic lipase, nucleotidase,
 breaks down proteins into peptides 64. State the fate of absorbed vitamins and minerals such
it refers to process of converting soluble milk 46. What is the other name sucrase
caseinogen to insoluble casein  activates procarboxypeptidase to carboxypeptidase as iron, calcium
(d) chymotrypsin Invertase
 pepsin can only act on milk when it is in casein 47. Name the digestive juice secreted in the mouth They are stored in the liver and released to the body
form  breaks down proteins and polypeptides into small according to its needs
peptides Saliva
 when milk is in casein form its stays longer in the 48. State the functions of the following intestinal enzymes 65. State the role of vitamins in the body
(e) Carboxypeptidase They are responsible for proper growth and
stomach thus more time for digestion (a) Maltase
23. state the 2 roles of the mucus present in the stomach  Breaks down some peptides into amino acids development proper body functioning and
Breaksdown maltose to glucose
(f) sodium hydrogen carbonate maintenance of metabolic processes in the body
 it prevents corrosion of the stomach walls by HCl (b) Sucsrase/invertase
 it prevents autodigestion by enzymes  neutralizes acidic chyme from the stomach Breaksdown sucrose to glucose and fructose
66. Different between macro/bulk nutrients and micro/  Body size- small sized people require more energy as 88. State 3 factors that make the duodenum alkaline
trace nutrients they have a larger surface area to volume ratio  Bile salts containing sodium hydrogen carbonate
Macronutrients refers to nutrients which are required hence more heat is lost to the surrounding thus  alkaline fluid secreted by the Brunner’s glands
in the body in large quantities while micro nutrients more energy required to regain the heat lost  pancreatic juice
refers to nutrients in the body in small quantities  Sex- males are more masculine while females have 89. give a reason why lipids cannot be assimilated
67. Give 3 examples of macronutrients and micronutrients more fats. Muscles burns more calories than fats they have large molecules
macronutrients Micronutrients thus more energy is required in males 90. state the role of amino acids
Potassium Iron  Environmental temperature- when temperatures of  they are condensed to form proteins
Calcium Iodine the surrounding are low more energy is required in 91. state 2 ways of preventing constipation
Sodium Copper order to generate heat for thermoregulation  by taking enough water
Magnesium Manganese  State of health- sick people require more energy to  eating food rich in roughage
Phosphorus Cobalt fight pathogens. Also lactating mothers require 92. give examples of vitamins and mineral salts stored in
Sulphur zinc more energy for breast feeding the liver
chlorine 77. State and explain the relationship between ruminants A, D, B12 ,
68. State 4 functions of water in the body and the bacteria in the caecum and appendix Iron, copper, calcium
 Serve as a medium in which chemical reactions Symbiosis; the ruminants benefits from enzyme 93. what will happen if there is lack of bile in the body
occur cellulase secreted by the bacteria while the bacteria it will lead to lack of fat-soluble vitamins in the body
 Serves as a solvent in which materials are benefits from shelter and nutrition due to poor absorption as their absorption is
transported in the body 78. Carnivores do not grind food but instead cut them into dependent on bile
 Serves as a coolant due to its high latent heat of small pieces and swallow them. Explain 94. name 2 inorganic ions and state their roles in the body
vaporization The flesh they eat do not have tough cellulose walls  calcium
 Takes part in chemical reactions such as hydrolysis thus mechanical digestion is not very important  formation of bone
69. Name the main carbohydrate present in the dietary 79. Carnivores eat less food and spend less time feeding.  necessary for muscle contraction
fibre Explain  necessary for blood clotting
Cellulose This is because most of their food they eat is digested  phosphorus
and absorbed  formation of bone and teeth (a) Name the structure above
70. Explain why dietary fibre has no nutritional value in
80. Describe the adaptations of rumen to their functions Villus
man  potassium
 Highly folded to provide large surface area for (b) What is the function of the part the part labelled E
Dietary fibre mainly contains cellulose and man does  transmission of nerve impulses
absorption Crypt of Lieberkühn
not secret enzyme cellulase to digest it  zinc
 Has numerous villi to increase the surface area (c) Giving your reasons sate whether the villus is from
71. Define constipation  necessary for the proper functioning of many
for absorption the ileum or the duodenum
It refers to the difficulty in removal of undigested enzymes as well as taste buds and smell
81. Explain why rabbits and rodents ingest their feaces Duodenum; presence of Brunner’s glands
food materials from the body through the anus receptors
Because there is very little absorption of products of (d) Name the labelled parts
72. Explain how dietary fibre prevents constipation  sodium
fermentation A- Microvillus
 It enhances peristalsis  maintenance of osmotic pressure of body B- Lacteal
 It absorbs water from the alimentary canal thus 82. List 4 stomachs of an herbivore fluids
 Rumen C- Vein
making faeces moist hence easy movement  transmission of nerve impulses D- Artery
73. Explain how roughage enhances peristalsis  Reticulum  iron E- Crypt of Lieberkühn
It adds bulk to food thus creating a grip for the gut  Omasum  formation of haemoglobin in body cells F- Brunner’s gland
muscles enhancing peristalsis  Abomasum  copper G- Arteriole
74. State 2 main functions of energy in the human body 83. Give a reason why the epiglottis closes the windpipe  necessary for proper utilization of iron H- Capillary network
Mechanical work during swallowing  necessary for some enzymes to act I- Lymphatic system
Basal metabolism To prevent choking by preventing the entry of food  manganese J- Epithelial cell
75. What is basal metabolism rate into the trachea  necessary for proper functioning of many cells K- Goblet cell
It refers to the minimum amount of energy required 84. State 3 reasons why the small intestine is highly folded  iodine 98. What is balanced diet
to drive vital life processes such as blood circulation,  To fit into the small abdominal cavity  formation of thyroid hormones It refers to a diet containing adequate amount of
breathing, active transport, thermoregulation  To slow down the movement of food thus giving  cobalt carbohydrates, fats, proteins, vitamins and inorganic
76. Explain 6 factors that affecting energy requirements in enough time for digestion and absorption  a constituent of vitamin B12 ions
man  To provide a large surface area over which 95. Name 2 minerals whose deficiency causes anaemia 99. What disease is caused by deficiency of the following
 Basal metabolism rate- this is the minimum amount digestion and absorption of food occurs Iron, cobalt (a) Vitamin niacin/Nicotinamide
of energy required to drive vital life processes such 85. Give a reason why bile is alkaline 96. How is the enamel adapted to its function pellagra
as blood circulation, breathing, active transport, Due to the presence of a basic salt; sodium hydrogen 97. Study the diagram below and answer the questions that (b) Iodine
thermoregulation. A person at rest requires energy carbonate follow Goitre
to drive this processes 86. State the role of enzyme enterokinase (c) Vitamin B2/Riboflavin
 Occupation- manual workers requires more energy It activates trypsinogen to trypsin Ariboflavinosis
than sedentary workers 87. Explain why digestion of starch stops in the stomach (d) Thiamine
 Age- young people require more energy since they Starch is digested into maltose by ptyalin which works Beriberi
are growing and hence have many actively dividing best under neutral/slightly alkaline conditions. Thus, (e) Vitamin D
cells the acidic conditions in the stomach denatures ptyalin Rickets
 (f) Calciferol for the action of pancreatic and intestinal enzymes. 107. The figure below is a diagram of an intestinal villus. (5) Night blindness (e) Deficiency of iron
Osteomalacial (in adults) Enzymes present in pancreatic juice are:
100. Give an account of the adaptations of (a) a named  ·Trypsin which digests proteins to peptides. (6) Beriberi (f) Deficiency of proteins
herbivore and (b) a named carnivore to its mode of  ·Amylase which digests starch to maltose
feeding.  ·Lipase which digests fats to fatty acids and (7) Pellagra (g) Excess carbohydrates and fats
 (a) A sheep has the following herbivorous glycerol.
adaptations:  (c) it produces bile. Bile salts carry out (8) Scurvy (h)Deficiency of iodine
 (i) It has a thick horny pad on the upper jaw over emulsification. This increases the surface area of
which vegetation is pressed by chisel-like incisors the fat enhancing the action of pancreatic lipase. (9) Osteomalacia (adults)(i) Deficiency of vitamin A
and canines on the lower jaw during feeding. 102. Why is eating a lot of sugary foods harmful to the
(a) A balanced diet is one that contains adequate amounts of
 (ii) It has a diastema which provides space for teeth? carbohydrates, fats, proteins, inorganic ions. vitamins, water
tongue movements that separate grass which is Sugar in the diet is fermented by bacteria in the and roughage to meet the body's needs. Too much or too
being chewed by cheek teeth and grass that is mouth leading to the formation of acid. The acid little of any of these substances causes a nutritional
newly gathered by front teeth. attacks teeth causing demineralization and eventual imbalance leading to malnutrition.
 (iii) Its premolars and molars have a large top destruction of the enamel. This leads to dental caries.
In addition, the acid attacks and destroys the gums (b) The non-nutrient components of a balanced diet are
surface which is worn out unevenly forming cusps water and roughage. Water intake is necessary to
which help in crushing and grinding of vegetation. and the periodontal membranes leading to gum  Giving your reasons, state whether this villus comes compensate for loses through sweat. urine, faeces, and
 (iv) The joints of the jawbones are loose allowing disease from the duodenum or ileum. expiration in order to maintain a relatively constant volume
up and down as well as sideways movements of the 103. Describe the digestion of proteins in the alimentary  It comes from the ileum as evidenced by the of the various body fluids.
lower jaw which aids in the grinding process. canal of an adult human being absence of Brunner's glands.
 What is the function of the part labelled E? Roughage provides bulk to the intestinal contents especially
 (v) Its rumen contains microorganisms that Digestion of proteins begins in the stomach where the in the large intestine. This stretches the intestine, stimulating
ferment cellulose releasing simple fatty acids that  Secretion of intestinal enzymes reflex peristaltic activity which helps in the movement of
enzyme pepsin breaks down proteins to polypeptides. In the
are absorbed by the animal. 108. (a) Describe the absorption of digested food in indigestible matter towards the rectum. In absence of
small intestine, the pancreatic enzymes, trypsin and
 (vi) The abomasum or true stomach and the small mammals. roughage. peristaltic movements are very slow or absent
chymotrypsin break down polypeptides and proteins to
intestine have a large variety of enzymes that digest peptides. The intestinal enzyme, called peptidase, completes leading to constipation.
(b) Name two nutrients that are absorbed in the mammalian
proteins, carbohydrates and fats to soluble the digestion of proteins by breaking peptides to amino (c)(1)g:(2) f;(3)h;(4)e;(5)i;(6)d;(7)b;(8)a;(9)c
gut without chemical digestion.
molecules that can be absorbed. acids
 (b) The dog has the following carnivorous  (a) The soluble products of digestion are absorbed 6.13 Explain the term phagocytic nutrition using a relevant
adaptations: 104. What is the role of HCl in protein digestion? in the small intestine especially in the ileum. example.
 (i) It has well-developed leg muscles that enable it  It converts pepsinogen to pepsin Monosaccharides, amino acids, vitamins and Phagocytic nutrition is a process through which cells take in
to run swiftly after its prey.  It provides an acid pH (pH 1.5 - 2.5) which is the inorganic ions are transported across the epithelial solid food material and digest it intracellularly. It is carried
 (ii) It has a strong sense of smell and sight which optimum pH for action of pepsin lining by a combination of diffusion and active out by protozoa such as Amoeba.
are important in hunting.  It unfolds (denatures) proteins enabling pepsin to transport into the capillaries of the villi. Fatty acids
work on them. Once an Amoeba comes into contact with solid food
 (iii) It has chisel-shaped incisors that fit closely and glycerol are absorbed into the epithelial cells material, it sends out finger-like projections called
enabling it to grip and tear off pieces of flesh close 105. State any three functions of the mucus which is of the villi and here they are re-assembled into pseudopodia. These surround the food material forming a
to the bone. secreted along the wall of the alimentary canal neutral fats. The fats are then shed into the lacteals food vacuole. The vacuolar membrane pinches off from the
 (iv) It has long, curved and pointed canines which  (i) It lubricates food which shed their contents into the lymphatic vessels plasma membrane and the vacuole migrates to the centre of
are used for piercing the prey, preventing its escape  (ii) It prevents digestion of the gut wall by and thence into the bloodstream. the cytoplasm. The vacuole fuses with one or more lysosomes
and often killing it. proteolytic enzymes.  (b) Vitamins and inorganic ions. which discharge digestive enzymes into it. These proceed to
 (v) It has carnassial teeth (upper fourth premolar  (iii) It makes food particles to adhere to one 109. (a) What is a balanced diet? digest the contents of the vacuole. The soluble products of
and the lower first molar) which are large and another during swallowing and during egestion. digestion, e.g. Monosaccharides and amino acids diffuse
(b) Which components of a balanced diet are not nutrients and through the vacuolar membrane and get into the cytoplasm.
powerful. They overlap like the blades of scissors 106. What triggers the secretion of gastric juice? Indigestible materials are expelled by a reversal of the
and are used for shearing and slicing flesh, why are they required?
(i) The hormone gastrin which is secreted into the mechanism of food vacuole formation, i.e. the vacuole moves
tendons and skin. (c)For each of the diseases in column A choose the matching to the surface and fuses with the cell membrane discharging
bloodstream by certain cells of the stomach in response to
 (vi) The other premolars and molars have jagged cause in column B. indigestible materials to the outside.
the presence of food in the stomach
edges that fit perfectly together making them ideal
110. The table below shows the results of experiments on
for cracking bones. (ii) Sight, thought, taste or smell of food. COLUMN A COLUMN B the rate of absorption of various monosaccharides by
101. Explain the role of the following organs in the pieces of living intestines and by pieces of intestines
digestion of food in a mammal:(a) Salivary glands (b) Mode of Exampl (1) Obesity (a) Deficiency of vitamin C poisoned with cyanide. The rates are given as relative to
Skull Special features
Pancreas (c) Liver. feeding e the rate of glucose absorption by living intestine
 (a) They produce saliva. Saliva contains the (2) Kwashiorkor
Absence of incisors and canines (b)Deficiency of the vitamin niacin
enzyme salivary amylase (ptyalin) which begins the (children) Rate of absorption
digestion of starch breaking it to maltose. It also A Herbivorous on upper jaw Presence of aSheep Sugar
lubricates food making it suitable for swallowing. diastema (3) Goitre (c) Deficiency of vitamin D By living intestine By poisoned intestine
 (b) It produces pancreatic juice. This contains glucose 1.00 0.33
sodium hydrogen carbonate (NaHCO3) and several Presence of long, curved and (d) Deficiency of vitamin B1
(4) Anaemia
enzymes. NaHCO3 neutralizes the acid of chyme B Carnivorous sharp canines Presence ofDog (thiamine)
galactose 1.10 0.53
and creates a pH of 7-8 which is the optimum pH carnassial teeth
 fructose 0.43 0.37 Pepsinogen and trypsinogen. (a)A parasite is an organism that lives in or on another (ii) It has a flattened body that offers a large surface area
organism and obtains from its nutrients and sometimes for absorption of soluble nutrients across the body wall.
xylose 0.30 0.31 (b) If they were secreted in an active form. they would shelter.
digest the cells in which they are formed and the lining of (iii) It secretes a lot of mucus and anti-enzyme substances
arabinose 0.29 0.29 the glands that secrete them. (b) Ectoparasites are those parasites that live on the that protects it from the digestive action of the host's
surface of their host's body. Examples are lice and ticks. enzymes.
111. Comment on these results. 116. (a) Describe the role of the rumen in ruminants. Endoparasites are those parasites that live inside their
host's body. Examples are tapeworms and Trypanosomes. (iv) Each worm produces millions of eggs that remain
Glucose and galactose are absorbed by both active transport (b) How do non-ruminant herbivores make use of cellulose? infective for long periods of time ensuring successful
and diffusion. Fructose is absorbed by diffusion with active  (a) It contains cellulase-producing microorganisms (c)A primary host, also called a definitive host is the transmission to the next host.
transport only playing a minor role. Xylose and arabinose organism that harbors the adult stage of a parasite. An
are absorbed by diffusion only. that ferment cellulose to simple fatty acids. These (v) It can respire anaerobically, enabling it to survive the
are absorbed through the rumen wall and carried intermediate host, also called a secondary host is the
organism that harbors the larval stage of a parasite. low oxygen content of the human's gut. (vi) It is a
112. In what ways is the mammalian small intestine by the bloodstream to various tissues where they hermaphrodite, which makes reproduction easier.
adapted for its functions? are used for respiration. The microorganisms also 7.2 (a) Symbiosis is a physical association between two
 ·It is long and the inner lining is highly folded manufacture microbial proteins. Upon the death of different organisms whereby both benefit from the 7.4 (a) Ascariasis (b) Elephantiasis (c) Malaria (d)
offering a large surface area for the digestion and the microorganisms which occurs in the relationship. Sleeping sickness (e) Potato blight.
absorption of food. abomasum. the microbial proteins are broken down
to amino acids and absorbed into the ruminant's (b) (i) Ruminal microorganisms secrete the enzyme 7.5 Adjustment of a parasite to its host ensures that a
 ·Its inner wall has villi and microvilli, which parasite continues deriving nutrients and some-times
bloodstream. cellulase which breaks down cellulose from plant materials
increase further the surface area for absorption shelter from the host while inflicting minimum damage.
 (b) Non-ruminant herbivores contain cellulase- to glucose. The microorganisms ferment the glucose to
 ·It has openings through which the pancreatic and producing microorganisms in the caecum. These simple fatty acids. These are absorbed into the ruminant's This is important to the parasite in that it has time to grow,
bile ducts open. absorbed in the colon and carried by the bloodstream and carried to the tissues where they are reproduce and spread. A poorly adjusted parasite normally
 ·It has goblet cells and Brunner's glands that bloodstream to other tissues where they are used oxidized for energy production. The presence of such kills its host quickly. In the process the parasite may
secrete mucus for lubrication and protection of the for Instead. They ingest their faeceswhich are microorganisms enables ruminants to utilize a wide variety damage itself or lose its source of food.
wall from digestive enzymes. subjected to further digestion and absorption in the of plant materials as a source of food. The bacteria are in 7.6 The tips of some of their hyphae produce the enzyme
 ·The Brunner's glands also secrete an alkaline stomach and small intestine. turn sheltered in a nourishing medium. cellulase. This digests the cellulose wall of host cells
fluid which maintains a pH of 7-8 which is the (ii) The protozoa Triconympha are found in large numbers enabling the hyphae to penetrate. Once inside, each hypha
optimum pH for action of intestinal enzymes in the alimentary canal of worker termites. They secrete the swells into a haustorium. This secretes enzymes that digest
 ·It has intestinal glands that secrete digestive PARASITISM,SYMBIOSIS AND SAPROPHYTISM enzyme cellulase which digests cellulose from plant complex organic materials in the cell. The soluble products
enzymes materials to glucose. Some of the glucose is absorbed and of digestion are absorbed into the cytoplasm of the fungi.
 (a) What is a parasite?
 ·It has a rich vascular network that supplies oxygen  (b) Differentiate between ectoparasites and used by the termite. The presence of such protozoa enables 7.7 The tips of hyphae that grow into the food source
and removes digested food endoparasites. In each case give two examples. termites to feed on wood materials. The protozoa are in secrete enzymes. The enzymes soak into the dead material
 ·The walls have muscles whose peristaltic  (c) With reference to parasites, explain the terms turn sheltered in a nourishing medium. and proceed to digest its constituents into simpler
contractions causes movement of food in the gut primary host and intermediate host. (iii) Bacteria of the genus Rhizobium invade the roots of compounds. Proteins are digested to amino acids,
and mixing of food with digestive enzymes  7.2 (a) Define the term symbiosis young leguminous plants and cause the root cells to carbohydrates to monosaccharides and fats to fatty acids
 ·The villi have a thin epithelium that allows soluble  (b) What are the benefits of the following multiply forming nodules. In the nodules, the bacteria fix and glycerol. The amino acids, monosaccharides, fatty
food materials to pass through easily associations? atmospheric nitrogen into ammonia. The ammonia is used acids and glycerol are absorbed into the cytoplasm of the
 ·The villi have numerous blood vessels to transport  (i) Ruminants and ruminal microorganisms. by both the bacteria and the plant to make amino acids. fungi.
 (ii) Worker termites and the protozoa Triconympha. The bacteria in return receive carbohydrates from the
absorbed nutrients and lacteals to transport 7.8 Saprophytic bacteria and fungi that live in the soil and
 (iii) Bacteria of the genus Rhizobium and plant. This association enables leguminous plants to grow
absorbed lipids leguminous plants. water bring about decay of dead animals and plants. The
113. Name one nutrient that is only transported in small in soils that are poor in nitrates. When the plants die, the organic materials in the dead bodies are eventually broken
 (iv) Mycorrhizal fungi and forest trees. nodules release ammonia into the soil where it is converted
quantities in the hepatic portal vein following  7.3 List five ways in which the pork tapeworm down to simple inorganic compounds such as carbon
absorption to nitrates by nitrifying bacteria. The nitrates can be taken dioxide, ammonia and mineral salts. These are taken up by
(Taenia solium) is adapted to life in human up by other plants.
 Fats alimentary canal. plants and used to make new organic compounds. This
114. Why is it necessary that blood from the digestive  7.4 Name the diseases caused by: (a) Ascaris (iv) Mycorrhizal fungi invade the roots of certain species of way, saprophytes help in the recycling of nutrients in
tract pass through the liver before entering the general lumbricoides (b) Wuchereria bancrofti (c) forest trees forming a root-fungus complex called nature. Were it not for their action of breaking down dead
circulation? Plasmodium vivax (d) Trypanosoma gambiensis (c) mycorrhiza. The fungi are able to absorb essential materials, essential nutrients would be locked in huge
Phytophthora infestans. nutrients like calcium,phosphate,potassium and other ions moulds of dead animals, faeces, leaves, branches and logs
The liver helps to regulate the level of nutrients entering which would be littered all over. The nutrients would be
 7.5 Explain the importance of adjustment of a from the soil better than the trees. Some of the nutrients
the general circulation in such a way that they are unavailable to subsequent generations of plants and
parasite to its host. are used by the fungus and the rest are passed to the tree.
relatively constant immediately after meals and during animals and life as we know it would cease.
 7.6 Explain how fungi that are parasitic to plants The fungus in return gets organic materials that are
fasting.
feed. manufactured by the tree through photosynthesis. This 7.9 (a) (i) Both are heterotrophic taking in ready-made
115. The enzymes pepsin and trypsin are secreted as  7.7 Explain how the fungi Rhizopus feeds. enables such trees to survive in areas where soils are food.
inactive precursors:  7.8 Describe the ecological importance of relatively poor in mineral salts.
saprophytes. (ii)Both never ingest their food but absorb soluble nutrients
(a)What are the names of the precursors? (b) Why are they  7.9 (a) State two similarities in the modes of 7.3 (i) It has suckers and hooks on its head for attachment from the surrounding medium.
secreted in an inactive form? nutrition of Rhizopus and tapeworms. to the intestinal wall of its host.
 (b) State two differences in their modes of nutrition.
(b) (i) Rhizopus produces the enzymes responsible for When they mature, the tips of the vertically 120. Bacteria are said to be alive but viruses are not. TRANSPORT IN PLANTS
digesting the food outside its body. While tapeworms rely orientated hyphae develop sporangia which are Explain.
on the host's enzymes to digest the food. black in colour.  Bacteria show all the characteristics that 1. Define the term transport and state 2 of its
 Dry bread does not have the necessary moisture to distinguish living from non-living things. Many of significance in organisms
(i) Rhizopus obtains its food from dead materials while support the growth of moulds. It therefore remains them are able to move about on their own. They It refers to the movement of substances from one
tapeworms obtain their food from living organisms. fresh. feed. Grow, reproduce, respire, and excrete. part of the body to another in an organisms
 (c) Pasteurization kills vegetative bacteria but not  Viruses on their own do not show any of the  Facilitates distribution of nutrients and oxygen
MICROORGANISMS to cells
their spores. When pasteurized milk is kept at room characteristics of living things. Outside their host
116. To what structure in higher animals and plants does temperature, the spores germinate into vegetative cells, viruses are inert particles which can be  Facilitates removal of waste products from living
the nucleus correspond? What is their main similarity bacteria and multiply causing spoilage. crystallized without loss of infectivity. They consist cells e.g. CO2
and their main difference?  The manufacture of UHT milk involves exposing it of only one nucleic acid either DNA or RNA which 2. State 3 examples of unicellular organisms
to high temperatures. This kills both vegetative is enclosed in a protein shell, such particles cannot Amoeba, paramecium, protozoa
It corresponds to the nucleus. They are similar in that both 3. Giving a reason name a method used by unicellular
bacteria and spores making the milk sterile. The move, feed, grow, reproduce or respire on their
carry the genetic material of the cell. They differ in that; organisms to transport substances in and out of their
treatment also denatures all enzymes naturally own. When a virus infects a cell, it directs the cell
the nucleus is enclosed by a membrane while the nuclear body
present in the milk. With no bacteria or enzymes, to make new viral particles. Therefore, although
body is not. Diffusion; they have a large surface area to volume
sealed UHT milk can last for a long time without reproduction does occur in viruses, they are totally
117. List three ways in which a bacterial cell differs from undergoing spoilage. dependent on the host cell for it to take place. ration
an animal cell. 119. The figure below is a diagram showing the growth 121. (a) Explain how microorganisms cause food 4. Explain why multicellular organisms have a
of a bacterial population following the introduction of spoilage. specialized transport system
 A bacterial cell has a cell wall which is absent in
a small number of bacterial cells in a new environment.  Microorganisms causes food spoilage by They have small surface area to volume ratio thus
an animal cell.
multiplying in it and producing enzymes that break diffusion cannot facilitate transport of substances
 ·In bacteria the nuclear material is not enclosed by
the various components of the food e.g. proteins, as organs and tissues are far from stirs that
a nuclear membrane.
carbohydrates and lipids into simpler compounds produce them
 ·A bacterial cell has no membrane bound 5. Name 3 processes that simple plants such as mosses
organelles like mitochondria and endoplasmic 122. Give reasons for the following:
(a) A surgeon normally wears a mask over his nose and and liverwort use for transport
reticulum. Osmosis, active transport, diffusion (they lack a
118. Give an explanation for the following observations: mouth during an operation
 If a surgeon sneezes or coughs during an specialized transport system )
 (a) A piece of meat placed in the open rots within 6. Describe the transport system used by highr plants
several hours while a similar piece placed in a deep operation, the mask traps liquid droplets released
from the nose or mouth. If the nose and mouth are Higher plants have a vascular system to transport
freezer stays fresh for several months. substances. The vascular system has xylem which...
 (b)A piece of moist bread placed in the open not covered, microorganisms in the droplets may
infect tissues of the patient being operated on. and phloem wich...
develops a greyish-black growth on its surface while 7. State 4 functions of roots in plants
a piece of dry bread under similar conditions (b) When one has a wound, it is advisable to clean it,
apply antiseptic and dress it  Absorption of water and minerals alts
remains fresh.
 (a) Name the stage labelled A -D.  Anchorage
 (c)Sealed pasteurized milk placed at room Cleaning the wound reduces the number of germs in it and
temperature will go bad within one day while sealed  (b) Explain what happens in each of these stages.  Storage of food in some plants
in the skin around it. Applying an antiseptic kills most of  Geseaous exchange in some plants
UHT (ultra heat-treated) milk remains fresh for a  (c) Suggest giving reasons, what would happen if the
the remaining germs. Dressing it prevents germs from 8. Draw a well labelled diagram showing the
long period of time at room temperature. temperature of the medium was lowered to 0℃ at
gaining entry (a) Transverse secation of a monocot and dicot root
 (a)Meat provides a very good medium for the point X.
growth of bacteria. When a piece of meat is placed  (a) A-Lag phase: B-Phase of exponential growth: 123. Differentiate between fungal spores and bacterial (b) Longitudinal section of a root
in the open, microorganisms from the air land on it C'-Stationary phase: D-phase of decline. endospores 9. State the functions of the following parts of a root
and multiply. They release enzymes that proceed to  (b) Lag phase - The number of dividing bacteria  Fungal spores are reproductive structures that (a) Root cap
digest complex organic compounds in the meat into are few and they are adapting to the new serve as a means of rapid multiplication when Protects the root tip as it pushes through the soil
simpler compounds causing decay. The process is environment hence their number increases slowly. environmental conditions are favorable. Bacterial particles
also aided by enzymes that are naturally present in  Phase of exponential growth -The bacteria are endospores are not reproductive structures. (b) Piliferous layer
the meat. already adapted to the new environment. They Instead, they serve as a means of surviving adverse Gives rise to the root hairs
 When meat is placed in a deep freezer, the low multiply very fast, doubling after every generation environmental conditions. Under such conditions, (c) Pericycle
temperature inhibits multiplication of any bacteria time. one bacterium forms one endospore. When Gives rise to lateral roots(it is below the endodermis
that may be present. The low temperature also  Stationary phase -Nutrients are getting depleted conditions become favorable, the endospore and is a single layer of cells)
inhibits the action of bacterial enzymes as well the and there is accumulation of toxic wastes. The germinates to give rise to one bacterial cell. (d) Cortex
action of enzymes naturally present in the meat. bacteria begin to die resulting in a balance between 124. Describe the economic importance of (a) Viruses Offers storage sites for food substances
Because of these reasons, the meat can remain the death rate and the rate of multiplication. (e) Endodermis
 Viruses cause some of the most serious diseases in
fresh for a long time.  Phase of decline-Nutrients are almost totally Regulates the amount of water and mineral salts
man and other animals as well as in plants. In
 (b) Bread provides a very good medium for the depleted and there is further accumulation of toxic entering the vascular bundle
humans, they cause such diseases as poliomyelitis,
growth of moulds. When a piece of bread is kept in waste products. Death rate gets higher than the (f) Root hairs
measles, smallpox, common cold, AIDS, rabies
the open, mound spores land on it from the air. rate of multiplication resulting in a decline in the Provides a large surface area for absorption of water
and many others. In plants they cause several
However. for the spores to germinate, moisture number of bacteria. and mineral salts
diseases including tobacco mosaic virus and
must be present. Moist bread contains the  (c) The number of bacteria would level off since (g) Vascular bundle
tomato bushy stunt.
necessary moisture and the spores germinate each the low temperature would inhibit their Transport materials in the plants
developing into a greyish mycelium or hyphae. multiplication. 10. State an afaptation of the following parts of the roots
 (a) Root cap (c) Has crosswalls that limit substances entering the
Has parenchyma cells that offer protection to the vascular bundle- endodermis
root tip as it pushes throught the soil particles (d) Also referred to as the parenchyma tissue- cortex
(b) Piliferous layer (e) Protects the root tip- root cap
Has special epidermis that gives rise to the root (f) Arises from the epidermal cells- root hairs
hairs (g) Provides a large surface area for aborption- root hair
(c) Cortex (h) Consists of starch grains- endodermis
Has parenchyma cells that offers site for packaging (i) Has a single layer of cells below the endodermis-
and storage of substances pericycle
(d) Endodermis (j) Consists of special epidermis – piliferous layer
Has a casparian strip which serves as a cross wall 19. Name 2 parts of the root that contain parenchyma
limiting the substances entering the vascular cells
bundle Pericycle; cortex
(e) Root hairs 20. Draw a well labelled diagram of a root hair cell
Are long to offer a large surface area for 21. State 4 fuctions of the stem
absorption of water and minrel salts  Storage of food in some plants such as the cactus
11. State the mai difference between the epidermal cels and sugarcane
of the roots and that of the stem  Transport of water and mineral salts
The epidermal cells of the roots has not cuticle  Support and expose the leaves to light
while those of the stem have a cuticle  Carries out photosynthesis in some plants e.g.
12. Explain why the epidermal cells of the roots lack cactus
cuticle  Conducts photosynthetic products to varous parts
For absorption of water to take place directly of the plants
across their surface  Gaseous exchange in woody plants
13. State the role fo the apical meristem of the roots
 Some plants sue for vegetative propagston e.g.
Has actively dividing cells which divide and adds to
cassava
the root cap whose cells become constantly worn
 Some plants carry out transpiration through their
out as it pushes throught the soil particles. This
stem
enable the root to eleongate
22. Draw a well labelled diagram showing internal
14. Describe 2 components of the endodermis
structure of a monocot stem and a dicot stem
 Casparian strip- is an impervious structure which
23. Name 4 plant tissues found in a monocot stem
serves as a crosswall which limits the entry of
 Phloem tissue
substances into the vascular bundle
 Xylem tissue
 Starch grains stores starch
 Ground tissue/cortex/ground parenchyma
15. State 4 adaptations of the root hairs to their function
 They are long to provide a large surface area for  Epidermis
absorption of water an mineral salts 24. Explain why stems of monocots always remain
soft/do not produce bark/wood
 They are numerous to increase the surface area
Theor stems lack cambium thus secodery growth
for absorption of water and mineral salts
do not take place
 They are thin walled to reduce the distance of
25. Draw a well diagram of a dicot stem
movement of water and mineral salts during 26. State the role of the waxy cuticle in some plant
absorption
stems
 They have numerous mitochondria to yiled energy Prevents excess water loss through transpiration
for absorption of mineral salts through active 27. The epidermis in stem of some plants do not
transport photosynthesize. Explain why
 They have large sap vacuoles to raise their osmotic They lack chloroplast
gradient thus enhancing water absroption 28. State 2 fucntions of the stem epidermis
16. State 3 adapattions of a root hair cell to its fuctions  Protects the inner delicate tissues from
Draw from the above mechanical damage
17. State 32 differences between a monocot and a dicot
 Prevents pathogenic entry
root
Young stems usually have stomata for gaseous
Monocot root Dicot root exchange
Phloem and xylem Xylem is star shaped 29. Explain how yound plants whose leaves have not
alternate in a ring with the phloem in grown are able to carry out gaseous exchange
between the arms The have stomata in their stem
Has a pith Lacks a pith 30. The cortex and the pith forms the packing tissue.
18. Name the part of the root described below Explain
(a) Gives rise to lateral roots- pericycle They fill spaces between other tissues
(b) Gives rse to root hairs- piliferous layer