HIV/AIDS; scientists all over the world collaborate

1. Describe the origin of the term biology in the fight against Ebola
It is derived from two Greek words;  Through environmental conservation- the fight to
bios meaning life and logos meaning save the ozone layer through international
knowledge agreements e.g. Kyoto protocol; management of
2. Define the term biology resources through international treaties
It refers to the scientific study of living organisms  Classification- scientists are using the same system of
3. State what the following branches of biology deals with naming organisms that is binomial system
a) Botany- study of plants 5. Define the 7 characteristics each living organisms posses
b) Zoology-study of animals 3 main  Nutrition- it refers to the process by which living
c) Microbiology- study of microscopic organisms branches organisms acquire and utilize nutrients
d) Mycology- study of fungi  Gaseous exchange- it refers to the process by which
e) Biotechnology- involves development of techniques for respiratory gases (oxygen and carbon (IV) Oxide)
application in biological processes pass across respiratory surfaces along a
f) Ichthyology- study of fish concentration gradient
g) Entomology- study of insects  Respiration- it refers to the chemical breakdown of
h) Ornithology- study of birds food in all living cells to yield energy, carbon (IV)
i) Herpetology- study of snakes and reptiles Oxide, lactic acid, ethanol and water
j) Virology- study of virus  Excretion- it refers to the process by which living
k) Cytology- study of the cell organisms separate and eliminate waste products of
l) Eurology- study of excretory organs metabolism from their bodies
m) Embryology- study of development  Growth and development- growth refers to the
n) Physiology- study of body functions irreversible increase in the size and mass of the body
(o) Anatomy- study of internal structures of an organism of a living organism; development refers to the
(p) Morphology- study of external structures of an irreversible increase in complexity in the structures
organism of a living organism
(q) Genetics- study of inheritance and variations  Movement and locomotion- movement refers to the
(r) Taxonomy- study of grouping and sorting of organisms change in position of a part of an organism;
(s) Ecology- relation of an organism and their surrounding locomotion refers to the change in position of the
whole body of an organism
(t) Biochemistry- chemistry of materials in tissues  Irritability- it refers to the ability of an organism to
(u) Histology- structure of tissues perceive changes in the environment and respond
accordingly
(v) Phylogeny- study of evolutionary relationships between  Reproduction- it refers to giving rise to a new
organisms individual of the same kind
6. Differentiate between the following terms
(w) Bacteriology- study of bacteria (a) Growth and development
(x) Phycology- study of algae (b) Movement and locomotion
*Refer to the answers from the previous questions
(y)Evolution- study of origin of organisms and their
progressive changes over a long period of time 7. State the importance of the following characteristics of
living organisms
4. State 4 importance of studying biology
(a) Nutrition- it enables metabolic activities to take place
 Enable learners acquire skills useful in daily life
 It is useful in solving environmental problems such (b) Gaseous exchange- it enables organisms to obtain
as pollution, poor health services, food shortage, oxygen necessary for respiration; carbon (IV) Oxide a
environmental degradation waste product eliminated
 It enables us to understand the body functioning (c) Respiration- it yields energy useful in growth and
 It enables us acquire knowledge useful in pursuing movement
careers such as medicine
 It enables us to acquire scientific skills such as (d) Excretion- facilitates elimination of waste products
analyzing data which would otherwise accumulate and become toxic
 It enhances international co-operation as explained hence causing harm to the organism’s health
below (e) Growth and development- Growth enables the organism
4. Explain 3 ways in which biology enhances international to acquire maximum size and mass necessary for proper
cooperation body functioning and for defense; development readies the
 Through medicine- scientists from all over the world organism for reproduction
have come together to develop a vaccine for
(f) Movement and locomotion- helps an organism look for 13. Name each of the following apparatus used in specimen 15. Study the diagram below and answer the questions that
food; look for mates; escape danger; look for shelter collection and in each give examples of organisms that may follow
be collected using the specimen
(g) Irritability- enables plants to obtain nutrients like
mineral salts, water etc.; enables animals to detect food and Apparatus Name; Function
utilize it; facilitate mating in animals; enables the Sweep net; used for
organism to seek favorable conditions while avoiding catching flying insects
unfavorable ones such as grasshoppers,
bees, butterflies
(h) Reproduction- prevents extinction of a particular
species of organisms; increases the number of organisms (a) Name the apparatus above and state its function
of a particular species; enables a particular species of Fish net; used for trapping Pitfall trap; it is used for catching crawling
organisms to be existent in one generation to another; small fish and other small animals
improves quality of species water animals such as (a) Name the apparatus above and state its function – (b) Name 3 organisms which may be collected using the
crabs, shrimps pooter; used for sucking small animals from rock apparatus above- spider, ant, cockroach, millipede
8. Define the term stimuli- it refers to responses by surfaces and tree barks (c) State 2 roles of Y
organisms to changes in the environment(singular- (b) Name 2 organisms which may be collected using the  keeps rain out
stimulus) tool above- ants, termites  prevent collected organisms from escaping
(c) Name Y and state 2 of its functions (d) Name 2 precautions that should be taken into account
9. Define the term specimen- it refers to the body or a part
Pair of forceps; used for Mosquito net; it prevents dirt from entering the when setting up the apparatus
of the body of a living organism being studied
picking up small stinging suction tube; it prevents the already collected  Choose a site where rain water will not run into the jar
10. State 4 precautions to take while collecting specimen animals such as organism from entering the suction tube ad
 The jar should be covered with a wood or a tile to keep
centipedes, spiders, subsequently into the mouth
 Collect the number required number to avoid rain out and prevent collected organisms from
scorpion (d) State the role of X- Allows the organism to get into
wastage escaping
Specimen bottles; used for the pooter
 Do not destroy the habitat of the organism (e) State 2 ways in which the efficiency of the above setup
keeping collected (e) Explain how collection of specimen using the tool
 Do not injure the organism because some parts may can be improved
specimen above works
be distorted  By adding an immobilizing liquid so that the
The opening of tube X is put into cracks in rocks or
 Harmful specimens should be handles with care to organisms does not move out
tree barks where the organisms are; the user then
avoid being injured. use of a pair of forceps is sucks in air through the opening of tube Z; this  By camouflaging the apparatus i.e. covering with
encouraged creates a partial vacuum inside the jar and air from vegetation
 Live organisms after the study should be returned to 14. Study the diagram below and answer the questions that the outside rushes into the jar to occupy the 18. Differentiate between the following terms
their habitat follow vacuum; this forces the organisms into the jar
 Highly mobile organisms should be immobilized through tube X (a). Autotrophic nutrition and heterotrophic nutrition-
using chemicals such as chloroform autotrophic nutrition is a type of nutrition where living
16. Study the diagram below and answer the questions that organisms manufacture their own food using simple
11. Name 2 chemicals used to immobilize highly mobile follow substances such as caron (IV) Oxide, water, mineral salts
organisms when collecting specimen and energy while heterotrophic nutrition is a type of
nutrition where living organisms feed on already
 Chloroform (tetrachloromethane)
manufactured food
 Diethylether (ethoxyethane)
(b) Partial/localized movement and locomotion/whole
12. State 5 differences between plants and animals movement- partial/localized movement refers to change in
(a) Giving a reason name the apparatus above and state its
Plants Animals function position of a part of an organism while locomotion/whole
 Able to make their own depend on readily made Hand lens/magnifying lens; it has a lens enclosed movement refers to change in position of the whole body of
food food in a frame attached to a handle an organism
 Most have chlorophyll lack chlorophyll It is used to enlarge objects (a) Name the apparatus above and state its use- Bait (c) Sexual and asexual reproduction- Sexual reproduction is
(b) Name parts A, B, C trap; it is used to attract and trap small animals
 have cellulose in cell Lack cellulose in cell walls a type of reproduction that involves gametes while asexual
A- Frame (b) Name 2 organisms which may be collected using the
walls reproduction is a type of reproduction that does not involve
B- Convex lens apparatus above- rat, mouse
 have limited movement Move freely
C- Handle gametes
(c) Name X- bait
 growth is only at the Growth is all over the body (c) State 3 maintenance practice for this tool (d) Aerobic and anaerobic respiration – aerobic respiration
meristematic tissues (intercalary growth)  Clean the lens using a soft tissue socked in ethanol 17. Study the diagram below is a type of respiration that occur in presence of oxygen
 do not have complex Have complex excretory  Do not touch the lens with dirty fingers while anaerobic respiration is a type of respiration that
excretory organs organs  Avoid any chances of scratches on the lens occur in absence of oxygen
 respond slowly to Respond quickly to (d) Write the formula for calculation of magnification
changes in the changes in the using the tool above 19. List 4 career opportunities in biology-dentistry,
environment environment Image/drawing length medicine, agriculture, public health, horticulture,
Object/actual length pharmacy
20. List 8 skills acquired while studying biology-
Classifying, analyzing data, measuring, evaluating data, l) A honey bee carrying pollen from one flower to (a) Understanding the differences between plants and their 44. State 2 differences between plants and animals in terms
recording data, observing, identification, drawing another offsprings- genetics of irritability
(CAMEROID)
26. Define a dissecting kit and state its use- it refers to a (b) Relationships between antelope and gazelle in their  Plants respond slowly to changes in the
21. Motor vehicles use energy and produce carbon (IV) biological set which consists of apparatus used to cut environment- ecology environment while animals respond quickly to
Oxide and water. Similar characteristics occur in living through an organism’s body or organ for the purpose of changes in the environment
organisms yet motor vehicle are not classified as living. List anatomic studies; cut through an organism’s body or (c) Solving parentage disputes- genetics
 Plants respond to changes in the environment
the other characteristics of living things that do NOT occur organ for the purpose of anatomic studies 36. Which scientist would suit your interest best if you are through tropic responses while animals respond to
in motor vehicles Living things grow and develop, interested in behaviour patterns in insects- ecologist changes in the environment through locomotion
reproduce, respond to stimuli(irritability) 27. List 4 tools found in a dissecting kit- scalpel, scissors,
dissecting needle, safety pins, hand lens scalpel holder, pair 37. Name any 4 international research centers conducting 45. Highlight 4 processes in man which are dependent on
22. State the importance of irritability to plants- enables of forceps biology related researches (institutions/organizations that respiration
plants to obtain essential products such as water and may provide employment to biologists)
mineral salts 28. Explain the necessity of specimen collection in biology  Secretion of substances such as enzymes
 International livestock research institute (ILRI)  Transmission of nervous impulses
23. What sort of biological knowledge would be useful to;  To facilitate comparative studies of different
organisms from different environments  International centre for insect physiology and  Growth and development
(a) Game warden- ecology  It saves time during biological investigations in the ecology (ICIPE)  Digestion
laboratory  Centre for disease control
(b) P.E teacher- locomotion and movement 46. Explain how a bean will attain nutrition
 Facilitates conservation and management of  Institute of primate research
(c) Tour guide- ecology organisms since a specimen may be used repeatedly It manufactures its own food through photosynthesis by
38. State 2 differences between respiration and gaseous
over a long period of time combining water and carbon (IV) Oxide using light energy
(d) Fisheries biologist- ecology exchange
 Enhances detailed study of biological principles trapped by chlorophyll
(e) Bee keeper- entomology  Respiration refers to the chemical breakdown of
29. State 4 methods of collecting insects’ specimen 47. Define magnification- it refers to the ratio between the
food in all living cells to yield energy, carbon (IV)
image length and object length
(f) Plant breeder- genetics, botany  Sucking from barks of trees or rock surfaces Oxide, lactic acid, ethanol and water while gaseous
 Physical picking using a pair of forceps exchange refers to the process by which respiratory 48. State 2 potential risks that a biologist is exposed to
24. How do plants compensate for their inability to locomote gases (oxygen and carbon (IV) Oxide) pass across
 Using a sweep net to catch flying insects during collection of animal specimen
 They are autotrophic i.e. they manufacture their respiratory surfaces along a concentration gradient
 Trapping crawling insects using a pitfall trap  Some of the animal specimen are stinging and can
own food thus no need to locomote in search of  Respiration is a chemical process while gaseous
30. Explain why it is important to preserve specimens exchange is a physical process cause potential harm
food
 Some of the animals have viruses that can be
 Through tropic responses- by moving some parts of 39. Plants do not have complex excretory organs like
 To enable reutilization of specimen to avoid wastage transmitted to the biologist
they are able to respond to stimuli i.e. roots animals. What could be the reason for this
growing towards water, light  To reduce the frequency of disturbance of the habitat
49. Define the term biologist
of an organism
 Most are bisexual thus to facilitate self-fertilization  Plants produce less toxic waste compared to
hence reproduction animals 50. Name the study of functioning of cells, tissues and organ
31. Name 2 chemical reagents that can be used to preserve
 Plants have the ability to absorb localized nutrients specimen  Plants reuse some of their wastes unlike animals
thus no need to move around  Plants deposits some of their wastes unlike TOPIC 3
 They have pollination mechanisms that ensures Formalin/formaldehyde/chloroform; alcohol animals 1. Define a cell
reproduction occurs without the need to move in 32. State one use of each of the following tools in biology It refers to the smallest basic and functional unit of
search for mates 40. What is likely to happen if waste products are not
removed from bodies of living organisms an organism
a) Pair of forceps- used for picking harmful 2. Study the diagram below of a light microscope
25. Name the characteristics of living organisms displayed organisms during specimen collection
by each of the following They would accumulate and become toxic thus poisoning
Used to hold specimen during dissection cells
a) Cow drinking water- nutrition b) Pair of scissors- cutting animal tissues during
b) Germinating maize grain- growth and development dissection 41. Name 3 structures that may enable an organism to detect
c) Bacterial spore dividing- reproduction c) Scalpel- cutting longitudinal and cross sections changes in the environment- eyes/ears/tongue/skin
d) Cheetah chasing after a gazelle- locomotion and during dissection
42. State 2 ways in which growth differs in plants and
movement 33. Name 3 industrial processes that depend on the animals
e) Football fan watching a game and cheering- knowledge of biology
irritability  In plants growth only occurs at meristematic tissues
f) Cow giving birth to a calf- reproduction  Bread baking industries while in animals’ growth occurs all over the body
g) Vine climbing up a tree- movement  Brewing industries  In plants growth is indeterminate i.e. takes place over
h) Athlete panting at the end of a race- gaseous  Manufacture of drugs in pharmaceutical industries a long unspecified period of time while in animals’
exchange  Manufacture of milk products such as yoghurt growth is determinate i.e. takes place over a specified
i) Mango tree producing juicy mangos- period of time
j) Seed producing heat during germination- respiration 34 State 2 characteristics of living organism specific to
k) Bursting of a sporangium in the Rhizopus sp- plants- autotrophic nutrition; localized movement 43. what is sensitivity- it refers to the ability of an organism
reproduction to detect changes in the environment and respond
35. Name a branch of biology that deals with the study of appropriately
 (a) Name and state the functions of the parts labelled  A light microscope can be used to view both alive An electron microscope uses beam of electrons  Transports lipids within the cell
with letters or dead specimen while an electron one’s only which have a shorter wavelength compared to the  Performs detoxification i.e. breakdown of
 A- eye piece lens/ocular lens- it has lenses that used to view dead specimen light used by alight microscope foreign substances such as drugs
contribute to the magnification of the specimen  Electron microscope produces only white and 15. Explain why when using an electron microscope, the  Synthesis steroids
 B- body tube/burrel- it holds the ocular lens and black images while a light microscope produces specimen under view must be dead (h) Golgi apparatus
the revolving nose piece coloured images This is because the specimen is placed in a vacuum  Secretion of substances such as proteins,
 C- Revolving nose piece/ turret- enables one to  In a light microscope the image can be viewed 16. Explain why the specimen under view is placed in a hormones and enzymes
change from one objective lens to another directly while in an electron microscope a screen vacuum when using an electron microscope  Manufacture of glycoproteins through the
 D- objective lens- brings the image of the is required to view the image To prevent the electrons from scattering modification of carbohydrates and proteins
specimen to focus and magnifies it 5. Define the term resolving power of a 17. Explain why a light microscope produces clear  Packaging and transport of cell secretions
 E- clip- it holds the prepared glass slide in position microscope/resolution images limited to a magnification of 1000times
 transport of substances out of the cell thus is
on the stage It refers to the ability of a microscope to distinguish This is because above this magnification the
found close to the cell membrane
 F- stage- is a platform where the slide containing between two close objects as separate entities images loses clarity
 synthesis of lysosomes
the specimen is placed 6. State 5 differences between a light microscope and 18. List the cell organelles observable when using a light
microscope  facilitates processing of cisternae
 G- condenser- concentrates light on the specimen an electron microscope (i) mitochondria
Light microscope Electron microscope Cell wall, cell membrane, cytoplasm, nucleus, sap
on the stage  Offers site for aerobic respiration
Uses light for illumination Uses beam of electrons for vacuole, tonoplast, chloroplast
 H- diaphragm- used to regulate the amount of (j) Lysosomes
illumination 19. Name the suitable stain to be used when one wants
light going through the condenser  Supply enzymes that destroys worn out cell
Uses glass lenses for Uses electromagnetic lenses to observe starch grains in a cell- iodine solution
 I- Mirror- it collects light from the source and 20. Explain why the resolving power of a light organelles
reflects it on the stage for specimen illumination magnification for illumination
microscope cannot be increase by increasing the  Kills bacteria in white blood cells
 J- hinge screw- used to incline the microscope Low resolving power High resolving power
number of lenses at very high magnifications the  Digest food materials in vacuoles (intracellular
into a required shape Low magnifying power High magnifying power digestion)
Specimen under view can Specimen under view is image produced losses its clarity
 K- Arm/limb- supports the stage and the body tube 21. Draw well labelled diagrams of the following cells (k) Centrioles (rod shaped and found close to the
 L- Base- provides firm and steady support be dead or alive dead nucleus)
when observed under a light microscope
 M- Fine adjustment knob- raises and lowers the Specimen are stained using Specimen are stained using  Forms spindle fibers that facilitates cell
(a) Animal cell
body tube over short distances bringing the image normal dyes complex stains division by pulling chromosomes apart
(b) Plant cell
into a sharp focus Specimen is mounted on a Specimen is mounted in the
22. What are cell organelles  Forms cilia and flagella in organisms where
 N- coarse adjustment knob- raises and lowers the slide and placed on the grid and placed in a vacuum these structures occur
It refers to structures found within the cell
body tube over long distances bringing the image stage in the open (l) Chloroplasts
Below are diagrams of plants and animal cells as
into a rough focus 7. Name the building block of organisms- cells
seen under an electron microscope  Traps light used in photosynthesis
(b) Give 2 reasons why the apparatus above should be 8. Name the living substance in cells in which other
23. State the functions of the following cell organelles  Stores pigment in plants(chlorophyll)
handled with care organelles are suspended- cytoplasm
(a) Cell wall (m) Vacuoles
 It is expensive 9. State 3 principles of the cell theory
 Gives the cell its definite shape i. Sap vacuole
 It is delicate  The smallest unit of a living organism is the cell
 Protects the cell against mechanical damage  Storage of cell sap for osmotic function
(c) State 4 precautions to observe when using the  All living thigs are made up of one or more cells
 Allow entry and exit of substances in and out  They create a turgor pressure contributing to
apparatus above  All cells arise from preexisting cells by cell
of the cell support especially in herbaceous plants
 Always use both hands when carrying the division
(b) Cell membrane  Storage of food substances such as sugars and
apparatus above. One hand holding the base and 10. Explain why it is possible to see finer details using a
 Selectively allow movement of substances in mineral salts
the other holding the arm light microscope other than a hand lens
This is because a light microscope has higher
and out of the cell  They store pigments that give various parts of the
 Do not place the apparatus at the edges of  Encloses the cell contents plant their color e.g. petals
benches resolving power
11. Define the term field of view (c) Cytoplasm  They may accumulate waste products and by
 Do not wet any part of the microscope to avoid  Offers site for chemical reactions products of metabolism thus providing a means of
It refers to the white patch of light observed under
rusting of the metallic parts  Carries other cell organelles and inclusions excretion
the eye piece lens when light is concentrated on the
 Make sure the low power objective lens click into (d) Nucleus ii. Contractile vacuole
stage of a light microscope
position before and after use  It controls cell activities such as protein  Osmoregulation
12. Explain why it is not advised to use the high-power
(d) State 2 precautions to observe in order to care for synthesis  excretion
objective lens together with the coarse adjustment
the lenses of the apparatus above  The nucleolus synthesize ribosomes iii. Food vacuole
knob
 Do not touch the lens with your fingers to This is because the coarse adjustment knob may  Nucleolus synthesis RNA  Storage of food
avoid making them dirty or wet ram the objective lens against the prepared glass  Carries genetic information in form of DNA  Digestion of food
 Dirty lenses should be cleaned using a special slide as it moves the body tube over long distances (e) Endoplasmic reticulum (n) Ribosomes
lens tissue or tissue paper moistened with ethyl thus may cause damage to the Lense or even crush  Transport substances such as lipids and proteins  Synthesis of proteins
to avoid scratching the slide within the cell (o) Pinocytic vesicle
3. What is the formula for calculating magnification 13. Where is the image projected onto when using an (f) Rough ER  Enables the cell to obtain solid substances
using a light microscope\ electron microscope  Transports proteins from the surrounding
Magnification= Eye piece lens magnification x Photographic film/fluorescent screen 24. Name the 2 type of vacuoles in unicellular
 Offers site for the attachment of ribosomes
objective lens magnification 14. Explain why an electron microscope has a high organisms
(g) Smooth ER
4. State 3 advantages of a light microscope over an resolving power than a light microscope  Synthesis lipids  Contractile vacuole
electron one
  Food vacuole The outer membrane is smooth while the inner Golgi apparatus. They are involved in the to allow making of thin sections
25. Explain why cell membrane is also referred to as membrane has infoldings called cristae (singular- processing and release of secretions to prevent distortion of the cell structure
bilayer crista) 51. With examples define the term secretion (c) Cutting thin sections
It consists of two protein layers sandwiched 39. In relation to mitochondria state 2 differences It refers to a substance made in a specific tissue or To allow light to pass through
between two lipid layers between active cells such as muscle cells; organ and taken to other tissues where it perform (d) Moistening of the prepared section
26. Describe the structure of the cell membrane spermatozoa and ess active cells such as fat cells fixations a specific function e.g. Digestive enzymes To prevent drying which would distort the cells
 It consists of two protein molecules sandwiched  Active cells have more mitochondria while less manufactured in various glands such as salivary Achieved by dipping the cut section in water
between two lipid layers active cells have less mitochondria glands which are then released to the alimentary (e) Mounting
 The lipids occur in two layers with their  Mitochondria of active cells have more cristae canal to digest food To make it convenient and allow light to pass through
molecules facing away from each other while the mitochondria of less active cells have 52. Study the diagram below and state what it represents (f) Fixation
 Some protein molecules occur in the inner and less cristae It shows the process of formation of Golgi Usually involves passing the slide with the preparation
outer surfaces while others transverse the 40. State one adaptation of lysosomes (note that apparatus and the release of secretions by spherical slowly under a mild flame
membrane lining forming pores through which lysosomes are dark and spherical) vesicles through exocytosis To kill the living tissue and make the preparation
substances pass  They have hydrolytic enzymes which destroy 53. Name 3 cells in plants that contain chloroplast permanent
Note that the membranes of other organelles such worn out cell organelles and old cells Palisade cells, spongy mesophyll cells, guard cells 60. Explain why it is easier to make microscopic
as mitochondria and the smooth ER share the xtic 41. Name the cell organelle which breaks down large 54. Describe the appearance of endoplasmic reticulum specimen of plants than of animals
structure typical of the cell membrane molecules such as proteins, carbohydrates ad lipids A system of parallel- flattened cavities and tubes This is because animal tissues are usually more
27. Name the chemical compound which makes up the into simpler compounds- lysosome which are lined by a unit membrane delicate than those of plants
cell wall of plant cells- cellulose 42. Explain how lysosomes destroy old or damaged cells 55. State 2 structural differences between the smooth ER 61. Differentiate between longitudinal sections and
28. Name the chemical compound which enables cell When a cell is old or damaged the membrane of and the rough ER transverse sections
walls to serve a supportive function in some trees lysosomes rapture releasing enzymes which then  Smooth ER has no ribosomes on its surface Longitudinal sections are those cut along the
Lignin proceed to digest the contents of the cell while the rough ER has ribosomes on its surface length of an organism’s structure while transverse
29. Study the diagram below of a plant cell and its 43. Describe how a lysosome destroys a damaged  Smooth ER is more tubular than the rough ER sections are those cut across the structure of an
adjacent cells and answer the questions that follow mitochondrion 56. State 5 differences between a plant cell and an organism
(a) Name part X and state its function A membrane forms around the mitochondrion animal cell 62. List 4 common dyes used to stain specimens before
 Plasmodesmata (minute channels which enclosing it in a vacuole Plant cell Animal cell viewing together with their colors
transverse the adjacent walls of cells) The lysosome fuses with the membrane and Has cell wall Lacks a cell wall  Iodine solution- brown
 They allow direct flow of substances between discharges digestive enzymes into the vacuole Usually, large Often smaller  Methylene blue- blue
neighboring cells The enzymes then digest the mitochondrion Regular in shape Irregular in shape  Eosin- red/pinkish
30. Name the continuous motion exhibited by the releasing its building blocks into the cytoplasm Has no centrioles Has centrioles  Fast green/ green
cytoplasm- cytoplasmic streaming Below are steps of how a lysosome destroys a worn- Some have chloroplasts Lacks chloroplast  Haematoxylene- purple/deep blue
31. Differentiate between eukaryotes and prokaryotes out cell organelle Stores starch oil and proteins Stores glycogen and 63. Explain the difference between the 2 types of
Prokaryotes are organisms whose nucleus or 44. Name the membrane that encloses a vacuole fats mounts that can be used when preparing slides
nuclei are not enclosed in a membrane while Tonoplast Has a large central vacuole Has no vacuole but Wet mounts are the most commonly used in school
eukaryotes are organisms whose nucleus or nuclei 45. Explain how a large central vacuole in a plant cell is when present is small laboratories where the specimen is placed on a
are enclosed in a membrane formed when the plat is young the cells have smell and found within the slide over a drop of water or any other liquid while
32. Name 3 components of the nucleus vacuoles which as the plant matures, they merge to cytoplasm fixed mounts are those made to make the specimen
 Nucleolus form the large central vacuole Cytoplasm and nucleus are Cytoplasm and nucleus hard/stiff for sectioning and to maintain the
 Chromosomes 46. State 3 components of cell sap in vacuoles of plants located towards the periphery occupy the central structure of the specimen by use of chemical
 Nucleoplasm Sugar, salts, waste products position fixatives such as 70%ethanol
33. State 4 cell activities controlled by the nucleus 47. State 3 functions of sap vacuole in plants 57. Distinguish between mounting and staining in 64. State 2 roles of fixation
Respiration, protein synthesis, cell division, RNA  Enables the plant cell to maintain optimum microscopy  Makes the specimen stiff/hard
synthesis, DNA replication osmotic pressure Mounting refers to the placing of a prepared slide  It helps maintain the structure of the specimen
34. State the role of nuclear pores in eukaryotes  It maintains the shape of the plant cell on their stage of a microscope while staining refers 65. Explain the reason why plants specimen are usually
Are channels of communication between the  It contributes to support of the plant to process of applying dyes on the specimen for placed over a drop of water when preparing slides
nucleus and the cytoplasm 48. Briefly describe the appearance of Golgi apparatus clear observations The water ensures that the cells remain turgid
Note the plural of nucleolus is nucleoli They appear as stacks of flattened vesicles 58. Distinguish between magnification and resolution of hence maintaining their shape
35. Name the diffuse tangle of threads found in the surrounded by a unit membrane with spherical a microscope 66. Explain why fixation is mainly done on animal
nuclear sap of the nucleus- chromatin vesicles at their ends which are pinched off from Magnification of a microscope refers to the ability specimen and not plants
36. Name 2 components of the chromatin the flattened vesicles of a microscope to enlarge tiny objects while One of the roles of fixation is to make the seaman
 Deoxyribonucleic acid (DNA) 49. State the role of the spherical vesicles found at the resolution refers to the ability of a microscope to stiff. Plant materials are already naturally stiff
 Some proteins end of Golgi apparatus distinguish between two close objects as separate 67. Give 3 examples of fixatives used in the school
37. State 2 functions of the nucleolus Facilitates exocytosis by transporting packaged entities laboratory
 Synthesis ribonucleic acid (RNA) substances to the cell membrane fusing with it then 59. Explain the essence of the following during  70% ethanol
discharging its contents microscopy  99% ethanol and 1% glacial
 Synthesis ribosomes
38. State the main difference between the inner Transports packaged substances such as proteins (a) Staining  Ethanoic acid
and lipids within the cell To enhance visibility of the cell organelles as the living 68. State 4 roles of a cover slip in microscopy
membrane of a mitochondrion and that of the outer
50. Name the most abundant cell organelle found in cells are almost colorless and translucent  It holds the specimen in position and forms
glandular organs such as liver. Explain your answer (b) Using a sharp razor blade an even surface
  It prevents the microscope’s objective les  Has a thin flexible cell wall to facilitate penetration Protect inner delicate tissues
from coming into contact with the trough the soil particles 74. Name the tissue in animals equivalent to epidermal
specimen  Has a cell sap with dissolved sugars and salts to tissue in plants- epithelial tissue
Note that 1 millimeter is equal to 1000 facilitate osmotic uptake of water from the soil 75. Epidermal cells in stems and leaves of plants are
micrometers  Thin cell wall to allow it to penetrate through the covered by a layer of wax. Name this layer and state
I micrometer is equal to 1000 nanometer soil particles its function- cuticle; it prevents excessive loss of
69. Define the term cell specialization (f) Red blood cell water through evaporation
It refers to the structural modification of newly  Are bicon cave in shape to provide a large 76. Name 2 type of cells found in the photosynthetic
formed cell in an organism in order to perform surface area for packing of hemoglobin tissue of plants
specific functions Palisade cells, spongy mesophyll cells
 They lack a nucleus when mature to provide
70. With examples define the following terms 77. Name 2 locations of the nervous tissue in man
more room for packaging of hemoglobin
(a) Cell- it refers to the basic structural and Brain, spinal cord, nerves
 They contain haemoglobin which has a higher
functional unit of an organism e.g. palisade 78. State 2 functions of dendrites in a nerve cell
affinity for oxygen enabling them to transport
cell, red blood cell, nerve cell  Connects the nerve cell to other nerve cells
oxygen
(b) Tissue- it refers to a group of cells modified to  It facilitates transmission of nervous impulses
 Are pliable to be able to squeeze between blood
perform the same function e.g. epithelial, 79. Define a muscle
capillaries
muscular, nervous and bone tissues in (c) Palisade cell It refers to a contractile tissue responsible for
animals; phloem, xylem, palisade mesophyll  Have numerous chloroplast that contain various kinds of movements in animals
and epidermal tissues in plants chlorophyll to trap light for photosynthesis 80. Explain the 3 different types of muscles in
(c) Organ- it refers to a group of tissues  Are tightly packed to trap maximum light for vertebrates
performing one or more functions e.g. kidney, photosynthesis  Skeletal muscles- these muscles are attached to
liver and heart in animals; leaves, stem, roots bones and are responsible for locomotion and
in plants other voluntary movements. They are made up of
(d) Organ system- it refers to several organs cylindrical cells
coordinated to bring about an effective action (g) White blood cell
in an organism e.g. circulatory, digestive,  Have a large prominent nucleus which enables
respiratory and reproductive systems them to control cellular activities
(e) Organism- it refers to a collection of organ  They exhibit amoeboid movement which enable
systems them to reach pathogens
71. Discuss the adaptations of the following specialized
cells
(a) Guard cell  Smooth muscles are found in the walls of the
 They have thick inner walls and thin outer walls digestive tract, respiratory tract, urinary tract,
to allow differential expansion hence opening (d) Nerve cell reproductive tract and the blood vessels. They are
the stomata made up of long, spindle-shaped cells with a
 Have extensions called axons and dendrites that
 They have chloroplast which enable them to transmits nervous impulses single nucleus. Their contraction helps in
photosynthesize movement of materials along these tubular
 They are bean shaped and are two to create an structures
aperture hence stoma (h) Muscle cell
 It has contractile fibrils which contract and
relax bringing about movement
 It has numerous mitochondria to yield energy
for movement

(e) Sperm cell  Cardiac muscles are the ones found in the walls
 It has a long tail-like extension for propulsion to of the heart. Their continuous contraction and
reach the egg relaxation without fatigue helps to pump blood
 It has an acrosome that contain lytic enzymes from the heart throughout the person’s life.
which digests the membrane of the ovum allowing Their cells have single nucleus and are joined
(i) Epidermal cells end to end forming long cylindrical muscle fibers
(b) Root hair cell the head to penetrate into the egg
 They are transparent to allow light to reach the
 It has an extension called root hair which provides  It has numerous mitochondria which yields
photosynthetic cells
a large surface area for absorption of water and energy for propulsion
 Some lie guard cells have chloroplast for
mineral salts  It has a nucleus which carries the genetic material
photosynthesis
 It has a large sap vacuole to raise its osmotic of the parent
72. Name 2 type of cells found in the epidermal tissue in
pressure allowing absorption of water through plants
osmosis Epidermal cells, guard cells, root hair cells (in
 Are thin walled to reduce the distance of movement roots) 81. State the roles of the following types of muscles
of water and mineral sats during absorption 73. State the role of the epidermal tissue in plants (a) Skeletal muscle
 are responsible for locomotion and other 86. Name 2 parts of the human body where microvilli 102. In many microscopic preparations of animal
voluntary movements. are found and state their role tissues, it is difficult to make out cell boundaries and
(b) Smooth muscle Small intestine, kidney tubules yet the disposition and number of cells can usually
Their contraction helps in movement of Increases the surface area for absorption be determined, which cell structures make this
materials along tubular structures such as the 87. Name 2 parts of the human body where cilia is possible
digestive tract located Nucleus
(c) Cardiac muscle Respiratory epithelium (it propels mucus and dust 103. Name the only cell organelle without a
Their continuous contraction and relaxation particles along it) membrane- ribosomes
without fatigue helps to pump blood from the 88. State 2 adaptations of the connective tissue 104. All cell organelles appear to be membranous
heart throughout the person’s life  Has strong fibers which enables it to connect in nature (except ribosomes). What could the
82. Explain the role of the following type of tissues in (f) vascular bundle other tissues and organs significance of this common feature be?
an organism  phloem translocate photosynthetic products  It has a matrix/ground substance in which Membranes tend to provide large surface area for
(a) Epithelial tissue  xylem translocate water and mineral slats various types of cells and connective fibers are reactions in the organelles
 Is a thin continuous layer of cells that forms the  xylem serves a supportive function embedded 105. State 2 factors that determine the choice of
external covering of the body of an organism and 89. Name the ground substance in a connective tissue microscope during biological investigations
various organs in the body Matrix  Size of the object to be viewed
 It lines and protect internal surfaces of various 90. Name 2 cells in the human body that lack a nucleus  Degree of details required
tubular structures in the body of an organisms when mature  Nature of the specimen
e.g. alimentary, respiratory, reproductive and Red blood cell, platelet 106. Name the cell organelle that would be
urinary tracts 91. Name the type of connective tissue in man that abundant in goblet cells. Explain
(b) Blood tissue forms a rigid framework called skeleton Golgi apparatus. Goblet cells are involved in the
 Transports oxygen from the lungs to other body (g) meristematic tissue Skeleton tissue secretion of substances and Golgi apparatus are
tissues 92. Name 2 kinds of skeletal tissue in animals incolved in secretion of substances
 apical meristem brings about primary
 Transports carbon IV oxide and waste materials Bone, cartilage 107. State 2 functions of nuclear membrane in
growth/increase in height/growth at the tips of
to various excretory organs 93. State one adaption of the bone as a skeleton tissue in eukaryotes
roots and shoots
 Fight diseases causing germs animals  Allow for communication between the nucleus
 lateral meristem is responsible for secondary
(c) Connective tissue It has calcium salts which makes it very hard and the cytoplasm
growth/growth of the girth
 Connects other tissues and organs holding 94. Name the mineral element responsible for the  Encloses the contents of the nucleus
them in position hardness of a bone- calcium 108. State the structural modification of a
(h) skeletal tissue
 It fills spaces between organs 95. State 2 adaptations of the parenchyma tissue Euglena cell
 supports the animal off the ground
 Has cells with large sap vacuole for storage of  Flagella for locomotion
 enables an animal to move food  Eyespot for photosensitivity
 protects vital organs such as heart, brain and  Has thin-walled cells to offer more room for 109. What might cell of the liver and glands have
lungs packaging of food in common
(i) reproductive tissue 96. Name 2 parts in a plant where meristematic tissues
responsible for the production of gametes, the They are all secretory
are found 110. What would happen if an organism lost
sperms and ova Cambium of stems and roots, the tip of stems and
83. state 3 different types of epithelial tissues control of its lysosomes
roots All its tissues would be destroyed due to excessive
columnar, cuboidal, squamous 97. Define the term phagocytosis
84. Differentiate between simple epithelium and production of lysosomes which would lead to self-
It refers to the process of ingesting and digesting a lysis
stratified epithelium pathogen 111. If we could control lysosome activity at
(d) Epidermal tissue Simple epithelium consists of one layer of cells 98. Name 3 cell organelles present in plant cells but different tissues how could this help in the treatment
 Protects inner delicate tissues from mechanical while stratified epithelium consists of two or more absent in animal cells
layers of cells of cancer
damage Chloroplast, cell wall, large central vacuole
85. Explain the following types of epithelial tissues in This could be used in destruction of tumors
 It prevents excessive loss of water through 99. A researcher was examining cells of an unidentified
animals 112. Give a reason for each of the following
evaporation animal organ under an electron microscope and (a) A microscope should never be put to close to the
 Protects inner tissues from infections (a) Epidermis found most cells rich in RER and Golgi bodies. State edge of the working bench during practical
(e) parenchyma tissue It refers to the epithelial lining of the skin which the function of the organ. explain It could easily topple over and fall leading to
 offers storage site for food in most plants covers the whole body and protects it from Secretion of substances; Golgi apparatus produce
mechanical damage, entry of pathogens and loss of damages and breakages
 forms packing tissue in some plants filling secretions such as enzymes while RER transports (b) The microscope mirrors and lenses should never
spaces between other tissues moisture. It is made up of stratified epithelium them
(b) Endodermis be touched with the fingers
 is partly responsible for maintaining the shape 100. Name the cell organelle that stores enzymes  to avoid any scratches on the lenses
of a plant It is the epithelium that lines the internal surface of Lysosomes; Golgi apparatus
blood and lymph vessels. It is made up of simple  to avoid any dirt on the Lenses which would
 partly responsible for maintaining the firmness 101. The diagram below is a structure found in lead to blurred images
epithelium living organisms
in some plants (c) The microscope should never get wet at all costs
(c) Mucous membrane(mucosa) (a) Name the parts labelled A, B and C
It lines the internal surface of the alimentary, To prevent metallic parts from rusting
A- Protein layer; B- phosphate group; C- lipid (d) When using the high-power objective lens, only
respiratory, reproductive and urinary tracts. It is bilayer
made up of simple epithelium the fine adjustment knob should be used for
focusing
 So that the objective lens can move the slightest 119. the diagram below represents a cell counted and recorded and the results tabulated as reticulum and Golgi bodies. What does this tell
distance preventing any chances of contact and organelle shown below about the organ
hence breakages of the slide and objective lens specimen No of stomata within
(e) Focusing should never be done downwards with the field of view It is a glandular organ involved in processing and release
the eye on the ocular Lense of secretions
B 80
To avoid any chances of the objective lens C 35 129. State 3 differences between cell membrane
making contact with the glass slide as this would (a) Give a reason why nail varnish was smeared on and cell wall
lead to damage of both the lense and the slide the upper surface of the leaves  Cell walls are thick, tough and rigid while cell
113. A microscope had the following To get the impression of the stomata membranes are thin and delicate
specifications (b) The impression was stained with methylene  Cell walls consist mainly of cellulose while cell
Low power magnification= x100 (a) name the cell organelle above blue. Explain. membranes consists mainly of lipids and proteins
High power magnification=x500 Golgi apparatus (not Golgi bodies) To color the specimen and create contrast  Cell walls are fully permeable while cell membrane
Under low power the field of view is 1500 microns. (b) give 2 reasons for your answer in (a) above between various parts of the stomata hence are partially permeable
calculate the field of vie under high power of the  has flattened stacks of membrane bound enhance visibility 130. state the role of cilia on epithelial tissues
microscope cisternae 125. Name the tissues that carry out the following
 has spherical vesicles at its ends functions in mammals Move materials over the epithelium
(c) name parts A, B, C (a) Supports the animal's body off the ground. - Skeletal
131. Name 2 mammalian organs where the
 A-Golgi body tissue
epithelium has cilia
 B- Golgi vesicle (b) Is responsible for movement. - muscular tissue
(c) Transports oxygen throughout the body. - blood  Trachea
 C- Golgi complex  Oviduct
tissue
120. Name the part of a plant cell that performs
Which combination above would give a wider field of view. (d) Transmits impulses- nervous tissue
the following TOPIC 4: CELL PHYSIOLOGY
Explain x100; the lower the magnification the greater the 126. The figure below is a diagram of a cell as
(a) Synthesize glucose- chloroplast 1. Defne the term cell physiology
field of view seen under the light microscope.
(b) Secrete enzymes- Golgi body It refers to the study of cell functions
121. Give 3 examples of semi permeable 2. Name 3 substances that the cell requires to perform its
114. What name is given to a photograph taken membranes in cells
by an electron microscope functions
Nuclear membrane, tonoplast, cell membrane Water, glucose, amino acids, vitamins, mineral
Electron micrograph 122. State the role played by the following in
115. State 2 differences between the following salts, gases (O2& CO2)
protein synthesis 3. What are physiological processes
(a) Mitochondrion and chloroplast (a) Nucleus- releases ribosomal RNA used by the
(b) Smooth endoplasmic reticulum and rough It refers to processes that involve movement of
ribosomes to synthesize proteins substances in and out of the cell
endoplasmic reticulum (b) Ribosomes
(c) Ribosomes and lysosomes 4. Name 4 physiological processes
Offers site for proteins synthesis Diffusion, osmosis, active transport, pinocytosis,
123. State 3 adaptations of the mitochondrion to phagocytosis, exocytosis
its functions 5. State 2 functions proteins in the cell membrane
 The inner membrane is greatly folded to form (a) Name the fluid found in the part labelled B and state  Forms the pores through which substances enter
cristae which offers a large surface area for its functions or leave the cell
respiration  Cell sap  Some serves as carriers which transport
 Have organic matrix that provides a suitable  It stores salt and sugars substances in and out of the cell
medium for respiratory reactions  It helps maintain an osmotic gradient for 6. Study the diagram below of a cell membrane and
 Bound by 2 membranes to protect the inner osmoregulation answer the questions that follow
delicate parts from external mechanical damage  Helps to regulate the shape and turgidity of the cell
and to maintain the shape of the cell (b) Name the structure that contains most of the DNA
 Has respiratory enzymes in the matrix to catalyze  Nucleus
respiratory reactions (c) Use the scale shown to determine the magnification
116. State 2 roles of ribosomes on the RER
 Synthesis proteins  The membranes are semi permeable to allow for
1 cm on the diagram represents 5 micrometer on the object
 Release proteins into the RER selective entry and exit of materials into the matrix (a) Name parts labelled A, B, C
117. Explain how sap vacuole of plants 124. In an experiment to determine the habitat of Since 1 cm = 10000 micrometer magnification is x2000 A- Phospholipid molecule
contribute to support in herbaceous plants two plants a leaf from each was obtained and B- Bilipid layer
smeared with nail varnish on the upper surface and 127. State 3 roles of parenchyma cells in a plant
They vacuoles tend to absorb water by osmosis and C- Pore
left for 3-5 minutes to dry. The thin film of nail  Storage of water
therefore swells, pushing the cytoplasm against the D- Protein molecules
varnish was peeled off with the leaf surface  Storage of food
cell wall. This makes plant cells turgid hence 7. Explain 3 properties/characteristics of the cell
impressions. The small part of the film from each  Fills the spaces between tissues membrane
support
leaf was mounted on a microscope glass slide  Some like chlorenchyma cells photosynthesize  Semipermeable- they selectively allow movement
118. Give 2 reasons why the cell above is
stained with methylene blue covered with a cover 128. when examining cells from an unidentified of substances in and out of the cell
palisade cell
slip and observed under a light microscope at x100. rabbit organ under an electron microscope you find
 Has tightly packed abundant chloroplast  Sensitive to pH and temperatures changes-
The number of stomata within the field of view was that most of the cells are rich in Rough endoplasmic
 It is cylindrical in shape extreme pH conditions such as high basicity or
acidity denatures the cell membrane. Moreover,
 high temperatures denatures the cell membrane It refers to the difference in concentration between (f) Surface area to volume ratio 23. Explain why osmosis is a special type of diffusion
as it is proteinous in nature the region of high concentration and the region of Diffusion rate s faster when the surface area to volume Because it involves movement of water molecules
 Polarized/possess electric charges- it has a net low concentration ratio is high and slower when the surface area to from a region of high concentration to a region of
positive charge on the outside and a net negative 14. What is a visking tubing volume ratio is great low concentration across a semipermeable
charge on the inside. The charges enables it to It refers to an artificially made cell membrane 18. State 4 roles of diffusion in membrane
attract materials into the cell and also detect which represents a cell membrane (a) Animals 24. Differentiate between osmotic pressure and osmotic
changes in the surrounding 15. Studt the diagram below and answer the questions that  It facilitates gaseous exchange across respiratory potential
8. State 2 advantages of the cell membrane being follow surface Osmotic pressure refers to the pressure exerted
polarized  It facilitates absorption of digested food from the against a semipermeable membrane to stop
 It enables it to detect changes in the gut osmosis/water molecules from the dilute solution
surrounding  It facilitates the elimination of waste from cells entering the concentrated solution while osmotic
 It enables it to attract materials to the cell  It facilitates exchange of materials between the potential refers to the hidden force of a
9. Name 2 substances that are mother and fetus concentrated solution which only becomes real
(a) Able to go through the cell membrane  It facilitates transmission of nervous when the solution is separated from distilled water
Water, vitamins, mineral salts, glucose transmission through the nervous system by a semipermeable membrane
(b) Are too large to go through the cell membrane (b) Plants 25. Name the instrument used to measure osmotic
Starch, protein molecules  Absorption of mineral salts from the soil pressure- osmometer
10. Define the following terms 26. Explain how the following changes when a plant cell
 Gaseous exchange
(a) diffusion- it refers to the process by which draws in water
(a) State and explain 2 observations made in the  It contributes to the transportation of
particles move from a region of high (a) Osmotic pressure
experiment photosynthetic products from the leaves to their
concentration to a region of low concentration Osmotic pressure increase because the water
 The contents in the visking tube turned blue plant parts
along a concentration gradient being drawn in dilutes the cell sap
black while the contents in the beaker remained  It facilitates removal of excess water from plants
(b) Osmosis- it refers to the movement of water (b) Osmotic potential
brown through transpiration
molecules from a dilute solution to a It decreases because the water being drawn in
 This is because the wall of the visking tube is  Diffusion of fragrances produced by flowers to dilutes the cell sap (osmotic potentials when
concentrated solution across a semipermeable
semipermeable thus allowed small iodine attract pollinators dealing with water is also called water
membrane/it refers to the movement of water
molecules to move from the beaker where they 19. Explain the importance of the flattened body of a potential)
molecules from their region of high
are highly concentrated into the visking tubing flatworm or leaves in plants 27. Study the diagram below and answer the questions that
concentration to a region of low concentration
where they are lowly concentrated. The iodine It provide a large surface area for diffusion follow
across a semipermeable membrane
the reacted with the starch to form a blue-black 20. Multicellular organisms have a small surface area to
(c) Active transport-it refers to the movement of
complex compound. On the other hand, the volume ratio thus diffusion occur slowly. Explain 2
molecules/ions from a region of low ways in which the problem of diffusion of materials
starch molecules are too large to move out of the
concentration to a region of high concentration has been resolved in these organisms
tubing thus the iodine in the beaker remained
against a concentration gradient by use of energy
brown  The development of highly folded respiratory
(d) Phagocytosis- it refers to the process by which
16. State 4 factors affecting the rate of diffusion and absorptive surfaces over which diffusion
specialized cells take in solid materials
Diffusion gradient, temperatures, type of diffusing has to take place
(e) Pinocytosis- it refers to the process by which
specialized cells ingest vesicles containing liquid
medium, size of diffusing molecules, diffusion  The body of some organs mat be flattened to
distance, surface area to volume ratio increase the surface area to volume ratio
which has dissolved substances
17. Explain how the following factors affect the rate of 21. State the main role of diffusion in living organisms
(f) Exocytosis – it refers to the process by which a
diffusion Gaseous exchange
cell releases secretory materials
(a) Concentration gradient 22. Study the diagram below and answer the questions that
11. A potassium permanganate crystal was introduced to
The greater the concentration gradient the faster the follow
the bottom of beaker containing water using a straw.
rate of diffusion and vice versa
State and explain the observations made
(b) Temperatures A solution of sucrose/common salt and some
After sometime a uniform purple solution was
Increase in temperatures result in an increase in the methylene blue was added to the thistle funnel
observed. The crystal dissolved and its particles
rate of diffusion as this increase the kinetic energy of whose opening at the base was covered with a sheet
spread from their region of high
the diffusing particles hence, they move faster and vice of a visking tubing. The solution of sucrose/common
concentration(crystal) to their region of low
versa salt was added slowly using a teat pipette. It was
concentration(water) to form a uniform purple
(c) Type of diffusing medium then clamped as shown and placed inside a beaker of
solution
Gases diffuse faster compared to solids and liquids water.
12. A student placed a perfume in one corner of the class
because the particles in gases are far apart thus face (a) State and explain the observations made
and stood in the other corner. State and explain the (a) State the main aim of the experiment
least resistance. On the other hand, solid particles are
observations made To demonstrate osmosis using a visking tube  The level of solution in the stem of the thistle
closely packed with together thus experience the funnel rises for some distance and then levels
The perfume will smell at the other corner because (b) State and explain the observations made in the
maximum resistance off
the perfume particles spread from their region of experiment
(d) Size of particles
high concertation to other parts of the room where  Volume of the contents in the visking tube  Water molecules moved from the beaker where
Smaller and lighter particles diffuse faster than larger
they are lowly concentrated using kinetic energy increase and the viscin tube becomes firm their concentration was high across the
and heavier particles
13. Define the term concentration gradient  Salt solution is hypertonic to the distilled semipermeable visking sheet into the thistle
(e) Distance of diffusion
water hence draws in water by osmosis swells funnel where their concentration was low. The
Diffusion rate is slower when diffusion distance is ling
and becomes firm column of water in the stem of the thistle funnel
and faster when the diffusion distance is short
 rose until pressure it exerted prevented further It refers to the firmness of a plant cell after i. Set up 1
net uptake of water drawing in water by osmosis wen place in a  Sugar crystals dissolves
(b) State one precaution to be observed during the hypotonic solution  Level of water in the petri dish drops
experiment 4. Plasmolysis ii. Set up 2
There should be no leakages at the base of the It refers to the process by which a plant cell loses  No observable change
thistle funnel water by osmosis and becomes flaccid after being iii. Set up 3
(c) In relation to the experiment above define the placed in a hypertonic solution  Sugar crystals do not dissolve
term hydrostatic pressure 5. Flaccid/limp cell  Water level in the petri dish remains the same
It refers to the height difference between the It refers to a plant cell whose cell membrane has (c) Explain the observations made in
original level of solution in the stem and the shrunk away from the cell wall after losing water i. Set up 1
final level by osmosis when placed in a hypertonic solution  The sugar crystals in the unboiled potato cube are
(d) Explain what happens when 6. Deplasmolysis moistened by the cell sap making a strong solution
i. Hydrostatic pressure is applied on the surface of the It refers to the process by which a flaccid plant cell
 Water is extracted from the cells adjacent to the
original solution column in the stem gains water and becomes turgid after being placed
cavity by osmosis.
This would prevent uptake of water from the in a hypotonic solution
 The cell saps of this cells become concentrated and
beaker 7. Incipient plasmolysis
extract water from the inner cells
ii. Pressure higher than the hydrostatic pressure is It refers to the point at which plasmolysis occurs
 The inner cells extract water from the cells at the
applied on the surface of the original solution 33. Explain what happens when a plant cell is placed in
periphery of the potato cube which then become
column in the stem distilled water
concentrated and extract water from the distilled
Water will flow from the solution into the  The distilled water is hypotonic to the plant cell
water in the petri dish
beaker a phenomenon called reverse osmosis thus the plant cell draws in water by osmosis
ii. Set up 2
28. A sample of RBCs was placed in distilled water in a  this increases the volume of the sap vacuole
beaker. State and explain the observations made after  In the unboiled potato without sugar crystals
which expands and pushes the cytoplasm and the
sometime water does not get into the cavity since there is no
cell membrane against the rigid cell wall
A reddish color was observed in the distilled water 38. Define wilting osmotic gradient between the cavity and the potato
 as more water is gained the sap vacuole exerts
after some time It refers to a condition in plants during dry weather in cells
turgor pressure on the cell wall and on the other
The red blood cells were hypertonic to the distilled which pants droop as a result of losing excess water by iii. Set up 3
hand the cell wall exerts an opposite and equal
water thus drew in water by osmosis and became evapotranspiration making the cells flaccid  In the boiled potato water does not get into the
force (wall pressure) which prevents the bursting
swollen and eventually burst as they lack a rigid 39. During the day plants droop. However, at night they cavity since the structure of the potato cells is
of the plant cell
cell wall(hemolysis) become firm. Explain. During the day plants droop as destroyed and they are no longer able to carry out
 when the plant cell is full/turgid wall pressure is a result of losing excess water by evapotranspiration osmosis
29. Explain what happens when a red blood cell is placed equal to turgor pressure
in a a concentrated solution making the cells flaccid. At night there is little or no 43. State the importance of osmosis in
34. name one instance when wall pressure is equal to
The concentrated solution is hypertonic to the red transpiration hence the cells become deplasmolysed (a) Microorganisms
turgor pressure in a plant cell
blood cell thus the red blood cell loses water by and become firm hence he plant becomes firm It facilitates uptake of water from the
when the plant cell is turgid 40. At night plant cells become deplasmolysed after being surrounding medium to the cells of
osmosis to the concentrated solution, shrinks and 35. explain what happens when a plant cell is paced in a
reduces in size(crenation) being flaccid during the day making the plant droop. microorganisms
concentrated solution
30. Differentiate between hemolysis and crenation/laking Explain an instance in which a plant dies due to (b) Plants
 the concentrated solution is hypertonic to the
Haemolysis refers to the process by which an wilting  It facilitates absorption of water from the soil
plant cell thus water is drawn from the plant cell If the water supply from the soil is insufficient the
animal cell swells and burst after drawing in water  Transport of water from the epidermal cells of the
into the concentrated solution through osmosis plant dies due to permanent wilting
by osmosis when placed in a hypotonic solution roots to the cells at the centre of the root
 this causes the cell membrane to shrink and pull 41. State 2 possible causes of wilting n plants
while crenation refers to the process by which an  Movement of water from the veins of leaves
away from the cell wall as the volume of the cell  If a plant loses more water than it gets from the
animal cell shrinks and reduces in size when after through the leave cells to the atmosphere through
sap decreases soil through transpiration
losing water by osmosis when placed in a transpiration
 the cell shrinks and is said to be  if a plant is exposed to a concentrated salt solution
hypertonic solution  Closing and opening of stomata
flaccid/plasmolyzed 42. Study the set up below and answer the questions that
31. State one way in which the body ensures that crenation  It contributes to support by making the cells turgid
36. name the condition responsible for holding leaves of follow
or haemolysis does not occur in cells in herbaceous plants and in non woody parts of
plats in a horizontal position- turgidity
Balancing of ions 37. explain what is responsible for holding a tomato plant the plants lie leaves and flowers
32. Define each of the following terms erect  Feeding in insectivorous plants
1. Turgor pressure (c) Animals
tomato plant is an herbaceous plant. It is remains
It refers to the pressure acting against the  Reabsorption of water at the kidney tubules
erect as it is filled with fully turgid cells tightly
cytoplasm and the cell membrane of a plant cell  Absorption of water at the intestines
packed together
when the plant cell draws in water after being  Reabsorption of tissue fluid into the blood stream
placed in a hypotonic solution at the venous side of the capillaries
2. Wall pressure 44. State 2 similarities between diffusion and osmosis
It refers to an inward pressure equal to turgor  Both involves movement of molecules from a
pressure exerted by the cell wall to prevent bursting region of high concentration to a region of low
of the plant cell after drawing in water when place (a) State the aim of the experiment concentration
in a hypotonic solution To demonstrate osmosis in plant cells  Both are passive processes i.e. do not require
3. Turgidity/turgor (b) State the observations made in energy
  Both depend on a concentration gradient  extreme pH conditions such as high acidity or  Procedure: Gently drop the permanganate crystal water is very important for maintaining the structural and
45. State 2 differences between diffusion and osmosis alkalinity results in low rates of energy production into the water. Leave the beaker undisturbed and metabolic integrity of plants, its deficiency leads to death of
 Diffusion involves movement of any type of thus slower rates of active transport/stoppage observe what happens. the plants.
molecules while osmosis involves movement of 50. state the roles of active transport in  Observation: The permanganate gradually
water molecules (a) plants dissolves and the purple colour spreads until it is 61. Name four processes in living things that depend on
 Osmosis occurs across a semi permeable  Absorption of mineral salts from the soil uniformly distributed in the water. active transport.
membrane while diffusion may occur in absence of  Translocation of photosynthetic products from  Conclusion: Molecules of permanganate diffuse  Absorption of soluble products of digestion, e.g.
semi permeable membrane the leaves to other plant parts from the crystal and spread throughout the water glucose and amino acids across the epithelial
46. Iodine is in high concentration in sea weed than in the (b) animals forming a solution. lining of the intestinal villi.
soil. Name the process by which the sea weed draws in  absorption of digested food from the alimentary 56. With reference to cells distinguish between a freely  Absorption of some mineral salts from the soil by
the iodine canal to the blood stream permeable structure and a semi-permeable structure plant roots.
Active transport  excretion of waste products from cells giving one example of each.
 Reabsorption of glucose, amino acids and
47. State and explain 2 factors affecting the rate of  transmission of nerve impulses  A freely permeable structure is one that allows
inorganic salts from the kidney tubules.
osmosis  reabsorption of sugar and salts in the kidney the free flow of molecules of different sizes across
 Temperature- as temperature increase the rate of it. An example is the plant cell wall.  Pumping of sodium and potassium ions across the
tubules
osmosis increases as the water molecules gain  A semi-permeable structure is one that allows nerve cell membrane during the transmission of an
51. name the process being described below
more kinetic energy certain molecules to flow across it but prevents impulse.
(a) white blood cell ingest pathogens such as bacteria
 Osmotic gradient- the higher the osmotic gradient phagocytosis others from doing so. An example is the plasma 62. In an experiment, equal volumes of blood were
the faster the rate of diffusion and vice versa (b) white blood cell feeds on microscopic organisms membrane of all cells. incubated for one hour with different salt
48. State 4 factors affecting the rate of active transport such as plasmodium- pinocytosis 57. Define the following terms in relation to a cell concentrations. After the incubation, the number of red
 Oxygen concentration 52. Give 3 roles of phagocytosis in living cells  (a) Isotonic solution blood cells in each setup was determined. The results
 Substrate concentration  Enables WBCs to ingest and destroy pathogens  (b) Hypotonic solution were as follows:
 Temperatures  Enables feeding in single celled organisms such  (c) Hypertonic solution
Final saltNumber of red blood cells after
 Enzyme inhibitor as amoeba or protozoa  An isotonic solution is one whose solute Set up
concentration incubation
 pH  Enables fertilization in some single celled concentration is similar to that of the cell contents.
49. explain how the following affects the rate of active organisms  A hypotonic solution is one whose solute A 0.9% Normal
transport 53. Describe how a WBC or Amoeba carries out concentration is lower than that of the cell
(a) oxygen concentration phagocytosis contents. B 0.5% Fewer than normal
 oxygen is required for energy production where it  When a WBC or Amoeba comes into contact with  A hypertonic solution is one whose solute
concentration is higher than that of the cell C 0.3% None
oxidizes glucose to yield energy for active transport the solid material e.g. food particle in the case of
contents.
 high oxygen concentration will result in more Amoeba or bacteria in the case of a WBC; it sends  (a)Account for the results in setup: (i) A (ii) C
energy being produced hence a faster rate of active out fingerlike projections which surround the 58. Name five processes in living things that depend on
osmosis.  (b) In what way would you expect the cells in setup
transport and vice versa material. B to differ from those in set up A?
(b) substrate concentration  The material together with the surrounding  ·Uptake of water from the soil into the root hairs of
plant roots.  (c)What observations would you expect to make
 glucose is required for energy production where it membrane forms the phagocytic/food vacuole with regard to the number and shape of red blood
is oxidized to yield energy from active transport  The surrounding membrane cuts off g=from the  ·Transport of water from the epidermal cells of the
root to the cells at the centre of the root. cells if the experiment was repeated with a salt
 lack of glucose results in low energy production cell membrane and the vacuole migrates to the solution at a final concentration of 1.4%?
thus a slower rate of active transport and vice versa centre of the cytoplasm  ·Reabsorption of water from kidney tubules.
 (a) (i) 0.9% salt solution is isotonic to red blood
(c) temperatures  The vacuole fuses with one or more lysosomes  ·Reabsorption of tissue fluid into the bloodstream
cells.
 respiration is an enzyme-controlled reaction which discharge its digestive enzymes into it at the venous side of the capillaries.
 (ii) 0.3 % salt solution is hypotonic to red blood
which are affected by temperature changes  The soluble materials are absorbed into the  ·Transpiration
cells. Water moves into the cells by osmosis causing
 at optimum temperatures active transport is faster surrounding cytoplasm 59. Explain why:-(a) red blood cells burst when placed in
them to swell and burst, a process called
due to sufficient energy production resulting from  In Amoeba undigestible materials are egested by a distilled water while plant cells remain intact.
haemolysis.
optimum enzyme activity reversal mechanism where the vacuole moves to  The red blood cells take in water by osmosis. They
 (b) Cells in setup B would appear larger than those
 temperatures below optimum inactivates the surface and fuses with the cell membrane and swell and exert pressure on the fragile plasma
in setup A.
respiratory enzymes leading to low energy discharges the undigestible materials to the membrane which then breaks.
 (c)The number would be normal. However, the
production hence a slower rate of active transport outside  Plant cells take in water and swell but do not burst.
cells would appear smaller in size and wrinkled
 temperatures beyond optimum denatures 54. Explain how a cell benefits from pinocytosis This is because, their tough cell wall can only
(crenated).
respiratory enzymes hence low rates of energy Once the pinocytic vesicle is in the cytoplasm it either stretch to a limited extent. Once fully stretched, the
production thus a slower rate of active transport raptures to release the dissolved substances of these cell wall resists further expansion of the cell and
(d) enzyme inhibitors are released after being broken down to smaller no more water is taken up.
60. Addition of large amounts of salt to soil in which TOPIC 5: NUTRITION
 presence of enzyme inhibitors e.g. cyanide slows molecules by digestive enzymes from lysosomes
plants are growing kills the plants. Explain. 1. Define nutrition
down the rate of active transport as it interferes 55. Describe a simple experiment to demonstrate diffusion
It refers to the process by which organisms
with respiratory enzymes in energy production of a solute
Plants normally grow in soils whose solute concentration is acquire and utilize nutrients
and vice versa  Materials: A beaker of water and a crystal of
lower than that of the cell sap. This enables the plants to 2. State 4 importances of nutrition in organisms
(e) power of hydrogen(pH) potassium permanganate.
take up water by osmosis. Addition of large amounts of salt  Growth and development
 optimum pH conditions result in more energy  For energy production
to the soil plants lose water to the soil by osmosis. Since
production thus faster rates of active transport
 To fight diseases
  Repair worn out body tissues Below is an internal structure of the leaf  It is transparent to allow light to penetrate and
3. Explain the difference between autotrophic and reach the photosynthetic cells
heterotrophic nutrition  It is impervious to water and gases thus prevents
autotrophic nutrition is a type of nutrition where excessive loss of water through evaporation
living organisms manufacture their own food  It is tough and therefore helps to protect the leas
such as vitamins, proteins, carbohydrates using from mechanical damage and entry of disease-
simple substances such as caron (IV) Oxide, causing microorganisms
water, mineral salts and energy while  It is shiny and therefore reflects heat preventing
heterotrophic nutrition is a type of nutrition overheating of the leaf
where living organisms feed on already 13. Name 2 mesophyll layers in a leaf
manufactured food (a) Explain the difference between the two
 Spong mesophyll layer 22. Name 2 parts of the plants where photosynthesis may
4. Explain the 2 different types of autotrophs and give  Palisade mesophyll
their examples occur
14. State 4 adaptations of the palisade cells Leaves, green parts of the stem
 Photosynthetic organisms- they manufacture  They are closely packed for maximum absorption
their own food using energy from sunlight e.g. 23. State 3 importances of photosynthesis
of light energy  It is the ultimate source of almost all organic
algae, green plants  They have large number of chloroplasts from
 Chemosynthetrophs- they manufacture their 10. State 3 functions of the following parts of a leaf matter in nature. The organic compounds
maximum absorption of light hence manufactured by green plants are consumed by
own food using energy from chemical (a) Epidermis photosynthesis
reactions/oxidation of inorganic compounds  Protects inner cells and tissues of the leaf from animas either directly or indirectly by feeding on
 The chloroplast move within the cytoplasm animals which have fed on the plants. Thus, green
e.g. non-green plants, some bacteria mechanical damage depending on the amount of light available plants are major sources of food in nature hence
5. Give 2 examples of chemosynthetrophs  Gives rise to the cuticle 15. Explain why chloroplasts in the cytoplasm of spongy
No-green plants, some bacteria called producers
 Allows light to penetrate to reach the palisade cells would be more on one side than the
6. Define photosynthesis  It is the only process that adds substantial
photosynthetic cells other
It refers to the process by which plants amounts of oxygen to the atmosphere in the air
 Prevents the leaf from entry of disease-causing During dim light they move to the upper parts of the
manufacture food using carbon IV oxide, water which is used by other organisms in aerobic
organisms cell allowing maximum absorption of light energy
and energy from sunlight respiration
(b) Cuticle and in bright light they move to the lower parts of the
7. Explain how a mushroom manufactures its food (refers  It utilizes carbon IV oxide thus helping maintain
 Protects inner cells and tissues of the leaf from cell which protects them from bleaching effects of
to classification II) its normal concentration in the atmosphere
mechanical damage intense eight intensities
8. Name one by-product of photosynthesis 24. What are mesophytes
 Allows light to penetrate to reach the 16. State 2 features of the spongy mesophyll layer These are plants which grow on well-watered soil
oxygen photosynthetic cells  It is composed of spherical/irregular shaped cells 25. State the role of lamina in lives
9. Write both a word and a chemical equation to  Prevents the leaf from entry of disease-causing  The cells are loosely packed to create air spaces Offers a large surface area for absorption of light
summarize the process of photosynthesis organisms  Contain chloroplasts for photosynthesis energy and gaseous exchange
 Waxy to prevent excess water loss from the leaf 17. Explain why the lower parts of the leaf is usually light 26. State 3 functions of the guard cells
in color than the upper side  Controls the opening and closing of the stomata
(c) Veins This is because palisade cells closer to the upper  Controls gaseous exchange
 Consists of xylem vessels which translocate water epidermis have more chloroplasts than the spongy  Controls the rate of water loss in a leaf
Below are external structures of a leaf and mineral salts from the roots to the leaves mesophyll cells closer to the lower epidermis 27. Study the diagram below ad answer the questions that
 Consists of the phloem tissue which translocate 18. Name 3 tissues that strengthens the veins in the leaves follow
products of photosynthesis from the leaves to of plants
other parts of the plants  Parenchyma tissue
 Contains strengthening tissues which enables it to  Collenchyma tissue
support the leaves (surrounded by tissues such as  Sclerenchyma tissue
parenchyma tissue, sclerenchyma tissue and 19. State the fate of the glucose manufactured during
collenchyma tissue which strengthen it) photosynthesis (4mks)
 Spreads the lamina enabling it to absorb light  Some is converted to sucrose and transported to
efficiently other parts of the plant
(d) Intercellular air spaces  Some is converted to starch and stored in the leaf
Allow efficient diffusion of gases and water vapor in form of starch granules
between the leaf and the atmosphere  Some is used in respiration
11. State 4 features/adaptations of the leaf epidermis 20. With an example state the fate of starch stored in the
 It is transparent to allow light to penetrate and leaf
reach the photosynthetic cells It is reconverted back to glucose when need arises
 It has close fitting cells surrounding the whole leaf e.g. at night when photosynthesis is not taking place (a) Name the cell organelles above and give a reason for
 It has stomata which facilitates gaseous exchange some is converted to glucose and used in formation your answer
 It has guard cells which control the opening and of cellulose Chloroplast; it is egg shaped; presence of grana
closing of the stomata 21. Study the diagram below showing the movement of (b) State the role of the organelle above
12. State 4 adaptations of the cuticle chloroplasts in response to light intensity in palisade Offers site for photosynthesis
mesophyll cells
 (c) State the importance of the organelle above in 31. Explain the term mosaic pattern/leaf mosaic and state (b) Hydrogen ions
taxonomy its importance to plants  Used in dark stage in carbon IV oxide fixation
Used to distinguish some pans cells from all other It refers to the leaf arrangement in most plants where where it is combined with carbon IV oxide
cells there is minimum overlapping of the leaves; this (c) Oxygen gas
(d) Name all the parts labelled with letters allows maximum absorption of light energy  Some is released into the atmosphere
A- Thylakoid disc 32. State 2 conditions for photosynthesis to occur  Some is used in cell aerobic respiration
B- Lamella (plural- lamellae)  Sunlight 40. Write both word and chemical equations to show the
C- Stroma  chlorophyll following processes
D- Lipid droplet 33. State 2 requirement/ raw materials for photosynthesis (a) Photolysis
E- Lamella (plural- lamellae)  Water
F- Granum (plural- grana)  Carbon IV oxide
G- Starch grain 34. Give 2 reasons why leaves of most plants appear green
H- Free ribosomes in color (a) State the aim of the experiment
I- Outer membrane  Presence of chlorophyll To determine the gas produced during photosynthesis
J- Inner membrane  Chlorophyll absorbs the blue and red wavelengths (b) Carbon IV oxide fixation (b) Why was a water plant used
K- Chloroplast envelope and most of the yellow and green wavelengths are It can carry out photosynthesis under water using
(e) Name the background material for the organelle reflected dissolved carbon IV oxide and at low light intensities
above- stroma 35. Name the 2 stages of photosynthesis and name the part (c) Why was sodium hydrogen carbonate added to the
(f) Using letters name the part were of chlorophyll where they occur water
i. Oxygen is produced- A It provides Carob V oxide necessary for
 Light stage/light dependent stage- granum
ii. CO2 fixation takes place- C photosynthesis by absorbing atmospheric carbon IV
 Dark stage/light independent stage- stroma
iii. Enzymes that facilitate light reactions of oxide
36. Define the following terms
photosynthesis are attached- F 41. What is the importance of light stage in the process of (d) State the observations made
(a) Photolysis
iv. Enzymes used in the dark stage- C photosynthesis Production of air bubbles which collected at the top
It refers to the process by which light energy trapped by
v. ATP is broken down to ADP and a Hydrogen ions and ATP is produced useful in the of the test tube
chlorophyll is used to split a water molecule to form
phosphate molecule- C dark stage during carbon IV oxide fixation (e) Name the gas being produced- oxygen
hydrogen atoms and oxygen gas
28. What is the general shape of a chloroplast 42. List 4 products of light independent stage of (f) State the role of the following in the setup
(b) Carbon IV oxide fixation
Biconvex shape photosynthesis i. Wooden support
It refers to the process by which hydrogen atoms
29. State the functions of the following part of the Glucose, water, fatty acids, amino acids Creates space between the funnel and the flow of
combine with carbon IV oxide forming simple
chloroplasts 43. Explain why plants store food inform of starch and not the beaker thus allowing free circulation of water
sugars such as glucose
(a) Grana glucose ii. Funnel
37. Describe the following stages of photosynthesis
 Offers a large surface area for the attachment (a) Light stage Glucose is soluble and osmotically active thus will Directs the air bubbles into the glass tube
of chlorophyll Occurs in the grana in presence of sunlight interfere with the osmotic pressure of cells thereby (g) State the likely identity of water plant X
 Offers a large surface area for the attachment Chlorophyll traps light energy which is then used to affecting cell functions while starch is insoluble and Canadian pondweed; Elodea
of enzymes required for the light reactions of breakdown water molecules into hydrogen ions and osmotically inactive thus will not interfere with the 46. Study the experimental set up below and answer the
photosynthesis oxygen gas in a process called photolysis osmotic pressure of the cells thus efficient cell questions that follow
(b) Starch grain The hydrogen ions are used in the dark stage during functions
Storage of starch carbon IV oxide fixation while the oxygen is released 44. Explain why the following is done when testing for
(c) Stroma into the atmosphere while some is used in respiration starch in a leaf
 Has photosynthetic enzymes which speeds up ATP is also produced in this stage (a) Using a leaf that has been exposed to light for 5 hours
the rate of photosynthesis (b) Dark stage The leaf has photosynthesized thus starch is present
 Offers site for CO2 fixation Energy absorbed in light stage is stored in form of ATP (b) Dipping the leaf in boiling water
(d) Lamellae which is then used in the dark stage To rapture the starch granules
Joins the grana Hydrogen ions from the light stage combine with (c) Dipping the leaf in methylated spirit’
30. Explain how chloroplasts are adapted to their functions carbon IV oxide to form glucose in a process called To decolorize it for clear observations to be made
 Have chlorophyll pigment which traps light carbon IV oxide fixation (d) Spreading the leaf on a white tile and flooding its
energy used in photosynthesis Some glucose is used in cell respiration; some surface with dilute iodine solution
 Has stroma where enzymes that speeds up converted to sucrose and transported toother parts of To test for the presence of starch. A blue-black (a) State the aim of the experiment
photosynthesis are located the plant and some converted to starch and stored in coloration would form showing the presence of To investigate if carbon IV oxide is necessary for
 Has granum for attachment of chlorophyll the leaf in form of starch granules starch photosynthesis
 Has grana which forms the main site for light 38. Name 3 products of the light stage of photosynthesis (e) State 2 possible control experiment for the above (b) In the setup above a destarched leaf is used. What is
reactions Adenosine Triphosphate (ATP), hydrogen ions,  Using a leaf from a non-green plants the meaning of destarching a leaf
 They have stroma which provides the favorable oxygen gas  Using a leaf that has been in darkness for sometime Removing starch from a leaf usually by placing the
site for dark reactions 39. State the fate of the following products of the light 45. Study the experiment setup below and answer the plant in the dark or sometime
 Has starch grains for storage of starch stage questions that follow (c) If leaf B was tested for starch state and explain the
 It is double membrane to ensure adequate (a) ATP observations that would have been made
protection of the inner delicate tissues  Used during the dark stage in carbon IV oxide Brown iodine color persists
 Has lipid globules for storage of lipids fixation to combine carbon IV oxide and hydrogen No starch produced since sodium hydroxide absorbed
ions caron IV oxide hence photosynthesis did not occur
(d) Name one suitable control experiment  Light duration (how long)
Similar setup without sodium hydroxide  Light intensity(type)
(e) Explain what observations would have been made if  Light wavelength(strength)
the flask had sodium hydrogen carbonate instead of 56. Explain how water affects photosynthesis indirectly
sodium hydroxide Slight water deficiency in a plant leads to closure of
On addition of iodine a blue-black coloration the stomata thus preventing carbon IV oxide from
would have formed. This is because sodium getting into the plant
hydrogen carbonate releases carbon IV oxide thus 57. Explain how light wavelength affects photosynthesis
photosynthesis would have occurred Chlorophyll absorbs mainly blue and red
(f) Name an alternative substance that can be used wavelengths and these are the ones used for
instead of sodium hydroxide b) Light intensity photosynthesis. Therefore, the wavelength of light
Potassium hydroxide; calcium hydroxide The rate of photosynthesis increases with increase in falling on a plant will influence its rate of
47. Study the experimental setup below and answer the (a) State the aim of the experiment light intensity. At higher light intensities the rate of photosynthesis e.g.
questions that follow To investigate the effect of varying light intensity on photosynthesis slowdown and levels off. At very high In forests leaves on tall trees absorb most of the red
the rate of photosynthesis light intensities chlorophyll is damaged and the rate of and blue wavelengths and the light that filters
(b) State the difference that would be observed if the setup photosynthesis falls through is of low intensity and in the green
is placed in sunlight and when placed in an open wavelengths. This reduces rate of photosynthesis in
cupboard plants growing in the forest floor thus only few
Many gas bubbles are released when the apparatus is shade-tolerant plants are able to survive in forest
placed out in the sun the least number of bubbles is floors
produced when the setup is placed in an open 58. Explain why only a few shade tolerant plants are able
cupboard. This is because the rate of photosynthesis to survive in forest floors
is dependent on light intensity Refer to answer above
(c) State the how light intensity is varied in the setup 59. Explain the term compensation point in relation to
above photosynthesis
By varying the distance between the light source and It refers to the light intensity at which the rate of
the bulb carbon IV oxide production by a plant in respiration
(d) Explain the shape of the graph that would be obtained is equal to the rate of carbon IV oxide consumption
(a) State the aim of the experiment if the results are plotted of light intensity versus the c) Temperature by the plant in photosynthesis and at this point all the
To investigate whether light is necessary for rate of photosynthesis determined by the number of The reactions of photosynthesis are driven by enzymes. sugar produced is used up in respiration
photosynthesis bubbles produced Enzymes work best in temperatures ranging from 35-40℃.
(b) State one precaution that should be carried out before At low light intensities the light intensity is directly At lower temperatures enzymes become inactive hence
the beginning of the experiment proportional to the rate of photosynthesis. However, slows down the rate of photosynthesis. If the temperatures
Destarching the leaves by placing the plant in the plot levels out at higher light intensities as other goes beyond 40℃ the enzymes are denatured thus
darkness for 48 hours factors become limiting photosynthesis stops
(c) State and explain the observations that would be made (e) State the role of the thick glass
if leaf A is tested for starch Helps to absorb heat from the lamp as heat also
The uncovered parts would turn blue black with influences the rate of photosynthesis
addition of iodine while the covered part would 49. What is a variegated leaf? It refers to a leaf with some
remain brown on addition of iodine. This is because parts of its lamina lacking chlorophyll hence has
the parts covered by the aluminium foil did not different colors
receive light energy thus no photosynthesis occurred 50. How can we confirm that photosynthesis has occurred
hence no starch is present while the uncovered parts in a leaf
received light thus photosynthesis occurred hence By testing for starch
presence of starch  During daylight green plants carry out both
51. State 4 factors that affect the rate of photosynthesis
(d) State the role of leaf B in the set up photosynthesis and respiration. The relative rates of
 Carbon IV oxide concentration
It serves as a control experiment d) Water both processes is greatly influenced by light intensity
 Light intensity
(e) State the conclusion made at the end of the experiment Plants with low amounts of water carry out  When light intensity is high photosynthesis proceeds at
 Temperature photosynthesis slowly while those with sufficient water a higher rate than respiration
Light is necessary for photosynthesis to occur  Water
48. Study the experimental setup below and answer the supply carry out maximum photosynthesis if other  Under these conditions carbon IV oxide production by
52. Explain how the following factors affect the rate of factors are optimum respiration is lower than the rate at which it is
questions that follow photosynthesis 53. State the role of light in photosynthesis consumed by photosynthesis thus the plants must take
a) Carbon IV oxide concentration It provides the energy required to drive the process of in carbon IV oxide from the atmosphere. In addition,
When carbon IV oxide concentration increases the rate photosynthesis. sugar production exceeds the rate of sugar utilization
of photosynthesis increases up to a certain level where 54. Explain why photosynthesis will proceed faster on a  When light intensity is low respiration proceeds at a
it slows down and levels off because at this point other bright sunny day than on a cloudy day higher rate than photosynthesis thus more carbon IV
factors become limiting Due to higher light intensity on a sunny day than on oxide is produced than it is being consumed and the
a cloudy day excess is released into the atmosphere.
55. State 3 qualities of light that affects the rate of
photosynthesis
 Under this conditions the rate of sugar production is  Fructose 30. Name 3 plant products of economic importance
lower than the rate of its utilization  Galactose composed mainly of cellulose
60. Explain why it is not safe to have potted plants in your All have 6 carbon atoms per molecule. They Paper cotton, hemp
room at night only differ in the arrangement of atoms in their 31. Name the polysaccharide described below
(Refer to the notes above) Write on the arrow the process and the enzyme. Do (a) Found in chloroplasts in form of granules- starch
structure
61. State the law of limiting factor also for the above (b) Stored in liver and muscles- glycogen
7. What is the general formula for monosaccharides
It states that a process influenced by several factors is 17. Name 2 plants which stores their carbohydrates in (c) Found in plant cell wall- cellulose
(CH2O) n where n= 6
governed by the factor that is in its lowest supply large quantities in form of sucrose (d) Found in cell wall of some fungi and exoskeleton
8. State 4 properties of hexose sugars
62. Study the diagram below and answer the questions that Sugar can, sugar beet of arthropods- chitin
 They are soluble in water
follow 18. Name the carbohydrate found in 32. State 2 functions of cellulose in plant cell walls
 They have a sweet taste
(a) Milk- lactose  Plays a supportive role
 They are crystalline in form (b) Germinating seeds- maltose
 They are reducing sugars e.g. they reduce  Plays a structural role
(c) Stem of a sugar cane- sucrose
copper II ions to copper I ions 33. State 4 functions of exoskeleton in arthropods
(d) Stored in mammalian muscles- glycogen
9. When glucose is added to Benedict’s solution and  Gives the organism its shape
(e) Most abundant in human blood- glucose
warmed for some time the color changes from blue to 19. State 2 ways in which hydrolysis can be achieved  Protects inner tissues from mechanical damage
orange. Explain  Boiling the solution in a dilute acid e.g.  Protects the organism from desiccation
Glucose is a hexose sugar/monosaccharide thus hydrochloric acid (in the lab)  Gives the organism their shape
is a reducing sugar. It reduces the blue soluble 34. State 4 functions of polysaccharides
 By action of enzymes (in living systems)
copper II sulphate present in Benedict’s solution 20. Name the enzyme found in the small intestine that  Are storage carbohydrates e.g. starch in plants
to copper I oxide which appears as an orange  Are structural carbohydrates e.g. cellulose
hydrolyses sucrose to glucose and fructose
precipitate Sucrase  When hydrated they form monosaccharides which
(a) Name the limiting factor between the following 10. State 2 functions of simple sugars
regions 21. State 3 properties of disaccharides can be oxidized to yield energy
 They are oxidized to yield energy in  They are soluble in water  Cellulose has commercial importance in formation
A- Light intensity
respiration of cotton, paper and cello tape
B- Temperature/ carbon IV oxide concentration  They are crystalline in nature
 They are building blocks of disaccharides and 35. State 2 ways of hydrolyzing polysaccharides to
63. Explain why plants at their natural environment rarely  They have a sweet taste
polysaccharides monosaccharides
if ever photosynthesize at their maximum potential  Lactose and maltose are reducing sugars
11. Differentiate between condensation and hydrolysis  Boiling them in presence of a dilute acid
This is because at any one point one or more of the while sucrose is a non-reducing sugar
Condensation refers to the process of chemically  Through the action of enzymes
various factors of photosynthesis become limiting 22. State 2 functions of disaccharides
combining two simple molecules to form a 36. Give 2 differences between monosaccharides and
64. Explain how yields of plats in greenhouses are  They can be hydrolyzed to monosaccharides
complex molecule with the product of a water polysaccharides
increased and oxidized to yield energy
molecule while hydrolysis refers to the Get them from properties
By increasing the rate of photosynthesis. This is  They are forms in which carbohydrates are
breakdown of a complex molecule to its 37. State 2 differences between fats and oils
through increasing factors such as carbon IV oxide transported in plants
constituent simple molecules in presence of water  Fats are found in animals while oil is found in plants
concentration and temperature artificially by use of 23. State 2 reasons why carbohydrates in plants are
12. What is the general formula for disaccharides/double  Fats are solids at room temperature while oil is liquid
methane burners transported in form of sucrose
sugars at room temperature
C12H22O11  Sucrose is soluble
Chemicals of life 38. Name the building blocks of lipids
13. Write an equation to show the formation of a  Sucrose is inert
1. Define chemicals of life 24. What is the general formula for polysaccharides Fatty acids, glycerol
disaccharide 39. State the main difference between carbohydrates and
These are chemical compounds that make up (C6H10O5) n where n is a large number resulting into a
bodies of living organisms large molecule lipids
2. With examples differentiate between the two types of 25. State 4 properties of polysaccharides Lipids have a lower concentration of oxygen per
chemical of life molecule than carbohydrates
 They are insoluble
Organic compounds are those composed of 14. Name the bond that holds two monosaccharides 40. For each lipid molecule there is one glycerol molecule
 They are not sweet
carbon in their structure e.g. carbohydrates, together and 3 fatty acids hence called a ___________
 They are not crystalline Triglyceride
proteins, lipids, vitamins and some hydrogen Glycosidic bond
carbonates while inorganic are those that lack  They are non-reducing sugars 41. Give examples of fats and oils
15. Write equations to show the formation of the following 26. State 2 differences between starch and glycogen
carbon in their structure e.g. water, mineral salts, (a) Sucrose Fats-beef fat, butter fat, lamb fat
acids, bases, buffers and some hydrogen  Starch is a storage carbohydrate in plants while Oil- corn oil, sunflower, groundnut oil
(b) Lactose
carbonates glycogen is a storage carbohydrate in animals 42. Name 2 chemical compounds that make up fats and
(c) Maltose
3. State 2 main functions of carbohydrates  Starch appears in cells in form of grains while oils- fatty acids, glycerol
Storage of food glycogen appears in form of granules 43. Give 3 examples of lipids in plants and animals
Production and storage of energy 27. Name 2 enzymes found in germinating seeds which Plants- phospholipids, oil
4. State the ration of the components of carbohydrates hydrolyses starch to glucose Animals- cholesterol, steroids, fats, wax
C:H:O=1:2:1 Amylase/diastase; maltase 44. If glycerol is the same in all lipids explain why coconut
5. State the general formula of carbohydrates 28. State the role of enzyme diastase/amylase oil is different from corn oil
(CH2O) n where n represents the number of Write the process on the arrow Hydrolyses starch to maltose They consist of different types of fatty acids combined
carbon atoms 16. Write an equation to show the hydrolysis of sucrose 29. Name 2 parts of the alimentary canal where enzyme to the glycerol
6. Give 3 examples of hexose sugars amylase/diastase is found 45. Name the bond between glycerol and fatty acid in
 Glucose Mouth; duodenum lipids
 Glyceride bond 52. Explain why fats provide a convenient way in which essential amino acids refers to those types of amino
46. Write equations to show the formation of the following energy yielding molecules can be stored for use when acids manufactured by only plants and thus animals
lipids need arises obtain them through diet while non- essential amino
(a) Triglyceride They are compact and insoluble acids refers to those which can be manufactured by
53. State the main function of oil in plants animals and thus, they do not obtain through diet
It is the main storage food in plant seeds 62. With examples differentiate between first class and
54. State the main advantage of fat to desert animals like second-class proteins
kangaroo rat and camel First class proteins refers to those that contain all the 70. State what determines the biological activity of a
When oxidized the fats release metabolic water which essential amino acids e.g. beef, milk, egg, beans while protein
can then supplement body water requirements second class amino acids are those that lack some The pattern in each protein molecule determined by
55. State 3 differences between lipids and proteins essential amino acids e.g. maize, millet, sorghum bonds linking part of the molecule together
 Proteins have nitrogen in their structure while lipids Note that a good protein diet should contain one or 71. Explain why enzymes are denatured in temperatures of
(b) Phospholipid
do not more of the animal proteins or a mixture of plant over 40℃.
 Some proteins have Sulphur in their structure while proteins This is because some bonds in the molecule are
lipids do not 63. State 4 properties of proteins broken at these temperatures leading to a change in
 lipids have a higher ratio of hydrogen to oxygen  They dissolve in water forming colloidal the structure of the proteins and thus loss of activity
than proteins suspension(slippery) 72. State 2 factors that can denature proteins
47. Study the diagram below and answer the questions that  Temperatures above 40℃
follow 56. name the building blocks/basic structural units of  They are sensitive to high temperatures
proteins  They are amphoteric egg have both exhibit both  Extreme pH conditions e.g. high alkalinity or
amino acids acidic and basic properties acidity
57. name the structural elements in proteins  Are sensitive to extreme pH conditions 73. Name the most abundant and important proteins in the
carbon, hydrogen, oxygen, nitrogen, sometimes 64. Name the property of proteins that enables to form human body
Sulphur, sometimes phosphorus conjugated proteins (when they combine with non- Enzymes
58. name the organic compound which is the most proteins) 74. Name 4 groups of enzymes in the human body and
(a) State what the diagram above represents abundant in the bodies of animals They are amphoteric their functions
Formation of a triglyceride proteins (makes of 50% of their dry weight) 65. State 4 functions of proteins  Enzymes- they catalyze biological reactions
(b) Name A, B, & C 59. show the structure of the following  They facilitate the growth and repair of cells  Transport proteins- they are found in blood where
A- Glycerol (a) amino acids  They yield energy when oxidized they bind and transport specific molecules or ions
B- 3 fatty acids from one part of the body to another e.g.
 they form respiratory pigments e.g. haemoglobin
C- Condensation haemoglobin
 they make antibodies which destroy disease causing
48. State one function of phospholipids  Antibodies- they bind to and destroy disease
microorganisms
Forms a structural component in cell membranes of causing microorganisms that invade the body e.g.
 they form structural components e.g. in cell
cells bacteria, viruses
membrane
49. State 3 properties of lipids (b) glycine  Hormones- are proteins that regulate certain
 they form enzymes which speed up (catalyze)
 Fats change to oil when temperatures are increased (c) alanine metabolic processes in the body e.g. insulin which
metabolic processes
and vice versa regulates the metabolism of sugar in the
66. name the proteinous respiratory pigment found in
 Insoluble in water but soluble in organic solvents mammalian body
(a) Red blood cell
 Lipids are inert thus are stored in tissues Haemoglobin  Contractile proteins- are components of
50. State the main reason why lipids are stored in tissues contractile tissues e.g. myosin found in muscle
(b) Muscles
They are inert/unreactive fibers responsible for movement
Myoglobin
51. State 4 functions of lipids 67. Define the following terms  Structural proteins- are important components of
 They are sources of energy. E.g. fats and oils are (a) Dipeptide various supportive tissues in the body such as the
oxidized to yield energy A combination of two amino acids bone, cartilage and connective tissue. Examples
 They are sources of metabolic water when oxidized The R-group is called the side chain and is one that are collagen, keratin
distinguishes one amino acid from another (b) Pentapeptide
which can then supplement body water A combination of five amino acids  Energy release- proteins can be used in respiration
requirements In glycine the side chain has one hydrogen atom and in to provide energy but only under conditions of
alanine the side chain has a CH3 group (c) Polypeptide
 They serve as shock absorbers thus protects vital A combination of many amino acids extreme starvation. Under these conditions tissue
organs such as lungs, heart, kidney and behind the There are 20 naturally occurring amino acids in proteins are broken down leading to emaciation
proteins and just like the letters of alphabets can be (d) Tripeptide
eyeball A combination of three amino acids 75. Name the transport protein in man that transports iron
used to make many words these amino acids can also
 They form structural components e.g. phospholipids 68. Name the bond between two amino acids to various parts of the body
be used to make thousands of different kinds of Transferrin
in cell membrane Peptide bond
proteins. Some contain all the 0 types while others 76. Give 2 examples of transport proteins in man
 They offer insulation against heat loss especially in 69. Show a diagrammatic representation of formation of a
contain only some Haemoglobin, transferrin
animals living in cold climates where they have peptide bond
60. name 3 components that plant use to manufacture their 77. Name the disease caused by the deficiency of hormone
large quantities of fat (subcutaneous fat layer)
amino acids insulin
under the skin
carbon IV oxide, water, mineral salts Diabetes Mellitus
 They facilitate buoyancy as they are less dense than 61. differentiate between essential and non-essential amino
water hence floating in aquatic animals such as 78. Give 2 examples of contractile proteins and state their
acids role
hippos, seals and whales which store a lot of fat in
their bodies
 Actin, myosin; they are found in muscle fiber and are  They are proteinases in nature thus are affected by It refers to chemical substances capable of slowing between the enzyme and the substrate. The rate of
responsible for movement extreme pH and high temperatures down enzyme activity or completely stopping it enzyme action doubles after every 10℃ increase.
79. Give 3 examples of structural proteins  They are very efficient thus are required in small 97. Differentiate between competitive enzyme inhibitor  At temperatures above 40℃ enzymes are denatured
Keratin, collagen, elastin quantities and non-competitive enzyme inhibitor thus enzyme reaction falls and at 60℃ the reaction
80. Highlight 2 methods through which proteins are 88. Explain how enzymes are affected by temperature Competitive enzyme inhibitors are chemical stops as all enzymes have Benn denatured.
hydrolyzed Temperatures above 40℃ denatures enzymes as they substances that compete for the active site of the  At temperatures below 0℃ enzymes are inactivated
 Through heating in an acid are proteinous in nature. This is irreversible. enzyme together with the substrate molecules thus therefore enzyme reaction decreases
 Through the action of enzymes Enzymes work best in temperatures between 35-40℃ slowing down enzyme activity while non-competitive
81. What are enzymes- these are proteinous substances while low temperatures inactivate enzymes hence enzyme inhibitors refers to chemical substances that
that speed up biological reactions slows down their rate of reaction. However, this is permanently combine with the enzymes hence
82. State 4 functions/roles of enzymes reversible by reverting the temperatures to optimum changing the structure of the active site of the enzyme
 Speeds up breakdown of food substances chemically range 98. Explain how competitive inhibition can be reduced
during digestion 89. A piece of liver of about 30g was dropped into a 250ml  Increasing substrate concentration
 Catalyzes respiration beaker containing 50ml hydrogen peroxide.  Increasing enzyme concentration
 Speeds formation formation photosynthetic products (a) State and explain the observations made 99. Explain how competitive inhibition can be reduced if
during photosynthesis A lot of fizzling and frothing is observed. This is due to other factors remain constant
 Facilitates detoxification through the breakdown of the rapid production of oxygen gas as hydrogen Increasing substrate concentration
harmful substances to form harmless one peroxide is broken down to water ad oxygen by 100. Give 3 examples of non-competitive inhibitors (b) pH/hydrogen ion concentration
83. Name one enzymes that performs detoxification enzyme catalase found in liver cells Mercury, lead, cyanide, silver, organophosphates  enzymes work best at optimum pH conditions
Enzyme catalase (b) Write an equation for the reaction that occurs 101. Explain why non-competitive inhibition cannot be  some enzymes work best in acidic conditions such as
84. Describe 2 methods of naming enzymes with examples decreased by increasing substrate concentration pepsin; some in neutral conditions such as salivary
 Trivial naming which involves adding the suffix - Non-competitive inhibition is permanent thus cannot amylase/diastase/ptyalin and some in alkaline
in to the name of the person who first discovered be decreased by increase the substrate concentration conditions such as trypsin
the enzyme e.g. ptyalin, pepsin 90. Enzyme catalase is known to have the highest turnover 102. Below are diagrams showing the two cases of  extreme pH conditions denatures enzymes thus
 Naming enzymes according to the substrates they number of all known enzymes. Explain what is meant enzyme inhibition decreased enzyme activity
digest or the processes they catalyze e.g. lipase by turnover number  most intracellular catalyzed reactions occur at
digests lipids and oxidase catalyze oxidation It refers to the number of substrate molecules neutral conditions
reactions converted to products per minute by a molecule of an
 Group name e.g. proteases are groups of enzymes enzyme
which digest proteins 91. Name 2 parts of the human body where enzyme
85. Differentiate between intracellular and extracellular catalase is present
enzymes and give examples in each Skeletal muscles, liver cells
Intracellular enzymes refers to enzymes which 92. During a reaction an enzyme remains unchanged.
catalyze reactions in cells in which they are produced Explain why new ones needs to be formed’
e.g. enzyme catalase, respiratory enzymes while Enzymes are proteinous and they become continually
extracellular enzymes refers to enzymes which destroyed
catalyze reactions outside cells in which they are 93. Reactions catalyzed by enzymes are easily reversible
produced e.g. lipase, maltase, rennin as shown below
86. State the roe of the following enzymes (c) substrate concentration
(a) Ptyalin- digest starch in the mouth increase in substrate concentration results in an
(b) Pepsin- digests proteins in the stomach increase in enzyme reaction up to a certain point
(c) Rennin- hydrolyses soluble milk protein where it slows down and levels off as all the active
caseinogen into insoluble casein Explain why the reaction would proceed in the direction x sites have been occupied. The leveling off can
(d) Trypsin- digests proteins in the duodenum and y reversed by increasing enzyme concentration
(e) Lactase- digests lipids If the substrates A and B are in high concentration the (d) enzyme concentration
(f) Urease- acts on urea reaction will proceed in the direction x which is towards increase in enzyme concentration results in an
the formation of the products C and D. if the products C Name the type of inhibition A and B increase in the rate of enzyme action up to a certain
(g) Dehydrogenases- catalyze reactions which
and D are in high concentration then the reaction will A- Competitive inhibition point where at slows down and levels off as other
involves removal of hydrogen from a substance
proceed towards the direction y which is towards the B- Non-competitive inhibition factors become limiting
(h) Oxidases- catalysis oxidation reactions
formation of substrates A and B 103. Name 4 factors affecting enzyme activity (e) inhibitors
(i) Reductase- catalyze reduction reactions
94. Define an active site/catalytic site Temperatures, pH/hydrogen ion concentration, presence of inhibitors slows down or completely
87. State 4 properties of enzymes
It refers to a precise place on the surface of an substrate concentration, enzyme concentration, slops an enzyme catalyzed reaction as they occupy
 They are substrate specific e.g. each enzyme has a
enzyme to which the substrates molecules get inhibitors, product concentration or alter the structure of the active site
specific substrate that it acts on e, g, lipase only acts
attached 104. Explain how the following factors affect enzyme (f) enzyme cofactors
on lipids
95. Name the product formed when an enzyme and a activity presence of enzyme cofactors enhance enzyme
 Enzymes are not affected by the reactions they (a) Temperatures
substrate molecule combine activity thus increases the rate of the enzyme
catalyze hence can be reused
Enzyme-product complex  Enzymes work best at optimum temperatures i.e. 35- reaction
 Most reactions catalyzed by enzymes are reversible 40℃. At optimum temperatures there is increased (g) co-enzymes
96. What are enzyme inhibitors
enzyme activity due to increased chances of contact
 presence of co-enzymes result in an increased rate Thus, metabolic processes breakdown resulting in 122. Explain how emulsification increase enzyme action 127. Differentiate between denaturation and inactivation
of enzyme activity as they activate enzymes deficiency diseases When lipids are broken down there is increased of enzymes.
(h) product concentration 112. Name one vitamin manufactured by animas and how surface area of contact with the enzyme thus
increase in product concentration slows down the it is manufactured increased enzymes action Denaturation is the destruction of an enzyme leading to a
enzyme action rate because the product becomes Vitamin D; it is manufactured when the skin is 123. Amino acids are said to be the alphabet of proteins. complete loss of enzymatic activity. It is brought about by
inhibitors exposed to sunlight If the letters A and B represent two different amino exposure to high temperature or extreme pH conditions.
105. name the enzymes that work best in 113. What are nucleic acids acids write down the sequence of all possible Inactivation is temporary loss of enzymatic activity and is
(a) acidic conditions These are complex nitrogen containing organic tripeptides that could be made from them brought about by exposure to low temperatures.
pepsin, rennin compounds found in all living things 128. What is the optimum temperature of an enzyme
(b) neutral conditions 114. Describe an experiment in which an enzyme is used AAA. AAB. ABA, ABB, BBB. BBA, BAB, BAA.
salivary amylase/diastase/ptyalin to breakdown a non-reducing sugar to reducing 124. What are the major functions of proteins in the It is the temperature at which the reaction proceeds at the
(c) alkaline conditions  To a test tube place 3ml of starch solution mammalian body? Give at least one example in each maximum rate.
trypsin, pancreatic amylase  Add 1cm3 of amylase/diastase solution case. 129. With reference to enzymes, explain what is meant by
106. with examples differentiate between enzyme  Warm the contents in a water bath whose  Catalysis: Many proteins function as enzymes the "lock and key hypothesis”.
cofactors and coenzymes temperature is maintained at 35℃ for 6 minutes catalyzing chemical reactions in the body, e.g.
enzyme cofactors refers to non prtoeinous  Add benedicts solution and heat amylase which catalyzes the hydrolysis of starch. Enzymes have a precise site on their surface called the
components of the enzyme which enhance enzyme  Color changes from blue to green to yellow and  Transport: Certain proteins which are found in active site or the catalytic site. It is here that substrate
activity e.g. iron, magnesium, zinc, calcium, orange blood bind specific substances in one part of the molecules bind. The shape of the active site and the
manganese while coenzymes refers to organic 115. Describe a test that can be used to confirm body and transport them to another part, e.g. presence of various chemical groups ensures that only
molecules from food substances such as vitamins emulsification in lipids haemoglobin which transports oxygen. those substrates with a complimentary structure can bind
which activate enzymes e.g. vitamin D, vitamin C and  Pour a little amount of cooking oil into test tube to it. For this reason. only specific substrates or a group of
 Defense: Certain proteins called antibodies bind
nucleic acid labelled A and B closely related substrates can bind to a particular and open
and destroy microorganisms that invade the body.
107. below is a graph showing the effect of substrate  Add 2cm3 of sodium hydrogen carbonate solution to it, only specific substrates will fit into an enzyme's active
 Regulation: Certain proteins act as hormones
concentration on the rate of enzyme catalyzed reaction test tube A site. Once the substrate dissociates to release the product
which help to regulate metabolic processes in the
 Rinse the measuring cylinder body.e.g. insulin which regulates carbohydrate and the enzyme. The free active site can bind other
 Add 2cm3 of water into B metabolism. substrate molecules.
 Shake the contents in both test tubes thoroughly and  Movement: Certain proteins are able to contract 130. Catalase has a turnover number of six million at 37
record your observations and to relax and are involved in movement. °℃. Explain what this means.
116. State the role of the following we=hen testing for Examples are actin and myosin which are found in
non-reducing sugars muscles. One molecule of catalase catalyzes the decomposition of six
(a) Hydrochloric acid  Structural: Certain proteins, e.g. collagen, are million molecules of hydrogen peroxide per minute.
Hydrolyses the non-reducing sugar into reducing important components of various supportive tissues 131. A food sample was made into a suspension and a
(a) explain the shape of the graph between the following sugar such as bone, cartilage and connective tissue. few drops of iodine was added into it. A blue-black
points (b) Sodium hydrogen carbonate 125. List the important functions of water in living color developed. A benedict’s test on the sample gave
i. A and B Neutralizes excess hydrochloric acid organisms. a clear blue solution. Another sample of the same food
Increase in substrate concentration results in an 117. Explain what happens during the emulsion test for  ·It is the solvent in which all biological reactions was made into a suspension with warm water (about
increase in the reaction rate because active sites of lipids take place. 35°℃). suspension. some millet seeds which had been
enzymes are available for the substrate molecules  Lipids are soluble in ethanol but insoluble in water  ·It is a reactant in many biological reactions. soaked for 48 hours were crushed and mixed with the
to bind  Water is miscible with ethanol photosynthesis. hydrolysis of food molecules such suspension. The mixture was incubated in a warm
ii. B and C  When ethanol with dissolved fats is mixed with as carbohydrates, fats and proteins. water bath for 6 hours. After incubation, the sample
The rate of the reaction slows down and levels off water it releases tiny fat droplets which then forms  ·It is the solvent in which raw materials like gave a negative test with iodine and a positive test with
with increase in the substrate concentration the white emulsion mineral salts and finished products like sucrose are Benedict’s solution
because all active sites have been occupied 118. Describe an experiment used to test for the presence transported in plants.  (a) What does the dark blue colour developed on
108. What are prosthetic groups in relation to enzymes of enzyme catalase in a food substance  ·It helps in the maintenance of a constant body addition of iodine indicate?
These are non-protein components of enzymes which  Put 2ml of hydrogen peroxide in a test tube temperature in warm-blooded animals because of  (b) What is a negative iodine test?
enhance enzyme activity  Drop the food substance into hydrogen peroxide its high specific heat capacity.  (c)Explain why the iodine test was negative after the
109. Explain how hydrolase enzyme slows down water re and observe  ·It is responsible for the turgidity of plant cells and
incubation.
absorption  Effervescence confirms the presence of enzyme hence the maintenance of an erect posture.
 (d)What is a positive Benedict's test and what does it
By increasing water use in hydrolysis catalase  ·It is a habitat for many plants and animals.
110. What are vitamins show?
119. Define emulsification 126. Explain why enzymatic reaction rate increases with
They refer to complex organic compounds required in Breakdown of lipids into tiny droplets done by enzyme increase in temperature  (e) Why was it necessary to soak the millet seeds
small quantities in bodies of plants and animals for lipase first?
proper health 120. Give a reason why emulsification is important As the temperature increases, the rate of the reaction also  (f)Suggest two control experiments for this
111. Explain how deficiency of vitamins in our bodies  For easy absorption of lipids increases. This happens because an increase in investigation.
results in diseases temperature increases molecular movement thus  (a) The dark-blue colour indicates the presence of
 Increase the surface area for enzyme action
Vitamins are coenzymes which activate enzymes and increasing the chances of collision between the enzyme and starch.
121. Give any other substance that can be used instead of
thus their absence causes the enzymes to be inactive. substrate molecules.  (b) A yellow or brown coloration.
ethanol in the laboratory
Sodium hydrogen carbonate solution
  (c) Because the starch had been hydrolyzed by case. digestion of starch would not take place. This 135. When plants are exposed to very hot and dry weather, the rate of photosynthesis falls. Suggest an explanation for this.
amylase and maltase released by the activated shows that the mobilization of enzymes require that
seeds. the seeds be activated by the germination process. The stomata close to reduce the rate of transpiration. This reduces the rate of CO2uptake and hence the rate of photosynthesis.
 (d) A positive Benedict’s test gives an orange 132. Three tubes each containing 1 ml. saliva and 1 ml. 136. What is the role of water in photosynthesis?
precipitate. It shows the presence of reducing water were incubated in water baths at different
sugars. temperatures as shown in the diagram below for 30 To supply hydrogen atoms which are used to reduce carbon dioxide.
 (e) The seeds had to be soaked to initiate the minutes. Another tube containing 1 ml. starch solution
137. The carbon dioxide concentration in the air of a tropical forest was measured during the course of a 24-hour period from
germination process which mobilizes the enzymes. was incubated for the same length of time in each
midnight to midnight. The graph below shows the results of the measurements. Examine it carefully and answer the
 (f) Control experiments: water bath. The contents of the tubes in each water
following questions:
 ·A suspension of the food sample is incubated with bath was then mixed and incubated for a further 30
crushed seeds which had been killed by boiling. In minutes. The contents of each tube was then tested for
this case, hydrolysis of starch would not take place. starch using iodine solution.
This shows that the hydrolysis observed in the test
samples is brought about by a substance which is
denatured by heat.
 ·A suspension of the food sample is incubated with
crushed seeds which had not been soaked. In this
 (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.  (a) What is the carbon dioxide concentration at (i) 3.00 a.m. (ii) 12.00 noon (iii) 4.00 p.m.?
 Tube B - digestion of starch took place as the incubation temperature was within the optimal range.  (b) Describe the pattern of carbon dioxide concentration as represented by the graph.
 Tube C -no digestion of starch as the enzyme was denatured by the high temperature.  (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.
133. In some plants, smearing the leaves with Vaseline on the lower surface will completely prevent photosynthesis. Suggest a  (d) Give a word equation for the process that utilizes carbon dioxide in the forest.
reason for this.  (e) Besides light, name four other environmental factors that would affect the carbon dioxide concentration in the forest.
 (f)What would happen if all the trees in the forest were cut down?
The leaves have stomata on the lower surface only. Therefore, smearing the lower surface with Vaseline completely blocks  (a)(i) 0.0425 (ii)0.0295
entry of CO2 which prevents photosynthesis from taking place.  (b) After midnight, the carbon dioxide concentration falls gradually until about 4.00 a.m. Thereafter, the concentration
134. State the adaptations of the following parts of a leaf falls rapidly reaching the minimum level at about 1.30 p.m. Then the concentration increases, gradually at first and
(a) Epidermis then rapidly reaching the maximum level at about midnight.
(b) Spongy mesophyll  (c) (i) As light intensity increases so does the rate of photosynthesis. This is accompanied by an increase in the uptake
(c) Palisade mesophyll of carbon dioxide lowering its concentration in the surrounding air.
 (ii) During darkness photosynthesis ceases taking place but respiration continues. Respiration releases carbon dioxide
Adaptations of A: into the surrounding air resulting in an increase in its concentration.
 (d) Carbon dioxide +Water →Glucose + Oxygen
 ·It is impervious to water and gases and therefore helps to reduce excessive loss of water by evaporation.  (e) Temperature, Air currents (wind), Soil water, Humidity.
 ·It is tough and therefore helps to protect the leaf from mechanical damage and entry of disease-causing  (f) Carbon dioxide level would remain constant at about the atmospheric level of 0.03% throughout the day.
microorganisms. 138. Why does leaving a plant in the dark for 48 hours result in destarching of the leaves?
 ·It is shiny and therefore reflects heat preventing overheating of the leaf.
 ·It is transparent and therefore allows most of light to pass through. Photosynthesis does not take place in the dark. However, respiration continues with glucose being broken down to carbon
dioxide and water. As glucose gets depleted, stored starch is hydrolyzed to glucose which is used in respiration or converted to
Adaptations of I: sucrose and transported to other parts of the plant. This eventually depletes the starch stored in the leaves.
 ·Its cells are irregularly shaped and loosely attached thus creating large intercellular air spaces which allow efficient 139. The diagram below shows the effect of varying light intensity on the exchange of carbon dioxide between the leaves of a
diffusion of gases and water vapour between the leaf and the atmosphere. green plant and the atmosphere.
 ·The walls of its cells are normally saturated with water, which allows transpiration to take place.
 ·Its cells have chloroplasts, which enable them to carry out photosynthesis.
Adaptations of J:
 ·It has columnar cells, which enables many of them to be packed together for efficient absorption of light.
 ·The cells have a very large number of chloroplasts.
 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.
 Remove the test tube from the water Final color is blue Absence of reducing sugars
bath
Add sodium hydrogen carbonate
dropwise until fizzing stops
Add Benedict’s solution whose
amount is equal to that of the food
substance
Heat the mixture in a water bath
Observe and record your observations
Lipids Rub a little amount of the food Presence of a permanent Presence of lipids
(grease/translucent substance on a filter paper translucent spot
spot test) Hold the paper above a flame to dry
Absence of a permanent Absence of lipids
Hold the paper against light. Observe
translucent spot
what happens to the spot
 (a) What is the name given to the point marked X? Lipids (emulsion Put a little food substance into a test Formation of a white Presence of lipids and vice
 (b)With reference to carbon dioxide exchange state what happens at point X. test) tube emulsion versa
 (c) Explain how the effect observed at point X occurs. Add 4cm3 ethanol to the food
 (d) Explain why there is a net uptake of carbon dioxide at light intensities above X. substance and shake thoroughly
 (e) What would happen to the plant if light intensity falling on it were maintained at X throughout? Transfers the contents of the test tube
 (f)What can you say about the exchange of oxygen between the plant and the surrounding air at light intensities below X? into another test tube half filled with
 (a) Compensation point. water
 (b) There is no net uptake or release of carbon dioxide by the plant. Proteins Put 2ml of the food substance into a A purple color forms Presence of proteins
 (c) The rates of respiration and photosynthesis in the plant are equal. Therefore, all the carbon dioxide released by clean test tube
respiration is used in photosynthesis. Add an equal amount of 10% sodium
 (d) At light intensities beyond X, the rate of photosynthesis is higher than the rate of respiration. This requires a net hydroxide solution and shake
uptake of carbon dioxide. Into the mixture add 1% copper II Blue color of copper II Absence of proteins
 (e) Growth would cease because all the products of photosynthesis would be utilized in respiration. sulphate dropwise and shake after sulphate is retained
 (f) The plant will take up oxygen from the surrounding air since the rate of respiration is higher than the rate of every addition
photosynthesis
FOOD TYPE PROCEDURE OBSERVATION INFERENCE/CONCLUSION
Starch Add 2ml of the food substance into a Color change from brown Presence of starch Ascorbic acid To 2ml of dichloro indophenol Blue DCPIP is decolorized Vitamin C is present
clean test tube to blue-black (vitamin c) (DCPIP) in a test tube add an equal
Add 3 drops of iodine solution to the amount of the sample solution and
DCPIP is not decolorized Vitamin C is absent
food substance and shake shake
Observe the color change and record Brown color of iodine Absence of starch
your observations solution persists
NUTRITION IN ANIMALS 2. Explain the following types of holozoic feeders and in
Reducing sugar Put 2ml of the food substance into a Color changes to green with Food substance contains a each give an example
clean test tube no further change on little amount of reducing 1. Explain the 4 types of heterotrophic nutrition with (a) Carnivores
Add an equal amount of Benedicts’ heating sugars examples of organisms They feed on flesh only e.g. lion, cheetah, leopard
solution to the food substance and Color changes to yellow Food substance contains an  Holozoic nutrition- organisms feed on solid materials (b) Omnivores
shake average amount of reducing obtained from plants and animals. it is carried out by They feed on both plants and flesh e.g. human
Note the color of the mixture sugars mainly mammals, birds, reptiles, amphibians and in being, pigs, dogs
Heat the mixture in a water bath Color changes to orange or Food substance contains a most invertebrates (c) Herbivores
Observe and record the color change brown high amount of reducing  Phagocytic nutrition- it is a type of nutrition were They feed on plants only e.g. cow, giraffe, zebra
sugars organisms feed on solid food materials by individual 3. With examples differentiate between browsers and
Blue color of Benedict’s Absence of reducing sugars cells e.g. Amoeba grazers
solution persists  Saprophytic nutrition- organisms feed on dead or Browsers refers to herbivores that feed on trees and
Non reducing Put 2ml of the food substance into a Final color is yellow, Presence of reducing sugars decaying matter e.g. fungi, bacteria shrubs e.g. giraffe, gazelle while grazers refers to
sugar clean test tube orange or brown  Parasitic nutrition- an organism called a parasite herbivores that feed on short plants e.g. cow, zebra,
Add 4 drops of dilute hydrochloric obtains foods from the living tissues of another wildebeest
acid to the food substance and shake organisms called the host and the host is usually 4. Define the following processes of holozoic nutrition
Heat the mixture in a water bath for 3 harmed e.g. most fungi, bacteria, protozoa (a) Ingestion
minutes  Symbiotic nutrition/ mutualism- in this mode both It refers to the process of taking food into the body
organisms benefit but one organisms benefits with through the mouth and swallowing it
nutrients e.g. Rhizobium bacteria in roots of legumes (b) Digestion
obtain nutrients and shelter while the plant benefits
from nitrogen fixation carried out by the bacteria
 It refers to the physical and chemical breakdown of  it is composed of collagen, calcium salts, and to offer surface against which vegetation is pressed it involves destruction of the pulp cavity and filling
large complex food molecules into smaller and simpler water and cut by the lower incisors the space with artificial material
molecules for easy absorption into the body 10. name 2 substances that hardens the enamel (g) have teeth with an open enamel 26. state 2 possible causes of tooth decay
(c) Absorption calcium phosphate, keratin to allow continuous growth to replace worn out  sugary foods
It refers to the uptake of soluble food materials from 11. dentine has a similar structure with the bone. Explain surfaces to grinding  poor dental hygiene such as not brushing teeth
the lumen of the digestive system through the lining of why it is harder than the bone 16. explain the importance of grinding in herbivores after every meal
the gut and finally into the blood stream it has a higher mineral content it enables them to breakdown tough cellulose cell  low levels of fluoride
(d) Assimilation 12. state the features and functions of the following types walls which enhances the subsequent chemical 27. state the effect of very high fluoride content in drinking
It refers to the incorporation of absorbed food of teeth digestion water
substances into cell metabolism (a) incisor 17. explain the reason for the following in carnivores it may cause browning of teeth (dental fluorosis)
(e) Egestion  has one root (a) have closely fitting incisors 28. explain how low fluoride content may cause tooth
It refers to the removal of undigested food substances  is chisel-shaped to seize prey decay
from the body (b) have long curved and pointed canines it results in weakening of the enamel thus
5. Study the diagram below of mammalian teeth and used for gripping food or cutting them into small to pierce and tear flesh as well as for attack corrosion by bacterial acids
answer the questions that follow pieces (c) have longitudinally ridged premolars and molars 29. state 4 signs of gingivitis/ periodontal disease
(a) Name the parts labelled with letters to increase the surface area for grinding  bleeding gum
(b) canine
6. Explain the following parts of the mammalian tooth in (d) have some teeth modified into carnassial teeth  sore gum
 has one root
terms of composition and function carnassial teeth  swollen gum
(a) Enamel  long for cutting flesh; crushing bones and slicing
 are cone-shaped  flabby gum
 Composition- it is composed of calcium phosphate meat
 it is sharp pointed  reddened gum
crystals bound together by keratin. It also has iron (e) their teeth have closed roots with only a small
it is used for holding and piecing food  soft gum
 Role- it forms an efficient hard biting and chewing opening
(c) premolar 30. state the effect of gingivitis
surface. Prevents the dentine from wearing out to allow food and oxygen supply to the tooth to
 has cusps/ridges on the surface to increase the it results in destruction of periodontal membrane
with use keep the tooth alive
surface area for chewing hence loosening of teeth and may eventually result
(b) Dentine (f) jaws are connected to powerful muscles
 has 2 roots in loss of teeth
 Composition- it has a high mineral content. It has in order to move the jaws up and down by
chewing and grinding 31. state the main cause of periodontal disease. Explain
strands of the cytoplasm from the cells of the pulp snapping
(d) molar 18. state 3 functions of carnassial teeth in carnivore how it causes the disease named
running through it dental plaque; if the bacteria multiply due to food
 Role- has living cells which gives rise to the  has 3 roots  cutting flesh
 has ridges/cusps particles if sugary foods in diet they invade the
enamel  crush bones
chewing and grinding gums and eventually the periodontal membrane
(c) Pulp cavity  shearing flesh/skin/tendons 32. what is dental plaque
 Composition- has a soft connective tissue. It has 13. differentiate between dental formula and dentition  serve as a pair of shears for slicing flesh
dental formula refers to the number and it refers to a soft invisible layer of bacteria which
blood vessels and nerve endings 19. state 2 adaptations of carnassial teeth in carnivores forms on teeth and is present in all mouths
 Role- the blood vessels supply the tooth with positioning of different types of te4eech in the jaws  have sharp edges for slicing flesh
of an animal while dentition refers to shape and 33. state 4 general method of preventing tooth diseases
oxygen and nutrients and carries away waste  has blades which overlap hence shearing  dental hygiene e.g. brushing teeth after every
specialization of teeth in an animal
products. The nerve endings detect here, cold and  are enlarged for crushing bones meal
pain 14. write the dental formula for the following animals
20. give the advantage of chewing food before swallowing  less sugary foods to reduce bacterial action in
(d) Cement (a) human being
 for easy swallowing the mouth
Role- fixes the tooth firmly to the jawbone (b) dog
(c) sheep  to increase the surface area for enzyme action  taking oral antibiotics to reduce bacterial load in
(e) Gum 21. give one modification of premolars and molars to their the mouth
Role- hold the tooth in place; prevents the tooth (d) goat
15. give reasons for the following in herbivores function in carnivores  visit a dentist regularly for dental checkup
from bacteria entry  have cusps to increase the surface area for
(a) enamel coating is thicker at the front than at the back 34. explain how the following prevent teeth diseases
(f) Periodontal membrane chewing (a) regular brushing of teeth
so that as the tooth wears out the sharp edge for
Composition- has connective tissues  have jagged edges to crack bones to remove food particles which may encourage the
Role- is a fibrous tissue which holds the tooth in the cutting vegetation is maintained
(b) canines are reduced or absent 22. name 2 periodontal diseases in man growth of bacteria
jaw  dental caries/tooth decay
to create a space called diastema which offer room (b) avoiding sugary food
7. Name the hardest organic substance known
for manipulation of food by the tongue by  periodontal disease reduce the bacterial action in the mouth
Enamel
separating the freshy cut vegetation and the 23. describe the cause of tooth decay (c) addition of fluoride into water
8. State 3 features of the enamel
chewed vegetation bacteria in the mouth respire using sugars to control tooth decay
 It is the hardest organic substance producing acids which corrode the enamel and (d) see a dentist regularly
(c) ridges of the upper teeth fit perfectly into grooves on
 It is non living may progress to the dentine if not treated early. so that small cavities or tooth decay can be detected
the lower teeth
 It is composed of keratin to allow for sideway grinding of vegetation Corrosion of the dentine may cause collapsing and treated early
 It has calcium phosphate crystals and iron (d) the teeth have a wide opening into the pulp cavity hence exposure of the nerve endings thus heat, (e) eating tough fibrous foods
9. State 3 features of the dentine (open roots) cold and pain can then be detected to exercise teeth thus encouraging proper blood supply
 has a high mineral content (e) to ensure a continued supply of adequate food and 24. state 2 possible solutions to tooth decay DIGESTION
 has living cells oxygen to the constantly wearing out tooth for its removal of the tooth, root canal treatment 1. define the term digestion
 has strands of cytoplasm running through it regrowth 25. explain how the root canal treatment works
(f) most have a horny pad
 it refers to the chemical and mechanical 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
breakdown of large complex food molecules into stomach- up and causes some HCl to leak into the esophagus haemoglobin
smaller and simpler food molecules cardiac sphincter and since the oesophagus has no mucus lining the bilirubin
2. differentiate between intracellular and extracellular 14. define churning HCl causes a burning effect producing pain hence 35. state what may cause absence of bile in the duodenum
digestion it refers to the mixing of the food together with the heartburn and its effect
intracellular digestion refers to the type of 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
digestion which takes place on cells while relaxation of circular and longitunal muscle layers while in the stomach little digestion of lipids and most of them will be
extracellular digestion refers to the type type of in the stomach walls forming chyme due to the presence of a muscle valve called pyloric voided in faeces
digestion which occur outside cells 15. define chyme sphincter which closes the entry into the duodenum 36. name 2 nucleases present in the pancreatic juice
3. differentiate between mechanical and chemical it refers to the porridge-like mixture... 27. name the muscular valve in which food enters the ribonuclease, deoxyribonuclease
digestion 16. describe the effect of arrival of food in the stomach duodenum 37. name 2 contents of the bile
mechanical digestion is the physical breakdown if arrival of food in the stomach stimulates hormone pyloric sphincter bilirubin, bile salts
food without its chemical nature being altered gastrin which then stimulates gastric glands which 28. state 2 effects of entry of food into the duodenum 38. name 2 bile salts
while chemical digestion refers to the breakdown of then release gastric juice into the stomach  it stimulates hormone secretin which then sodium taurocholate, sodium glycocholates
food by digestive enzymes thus the chemical nature 17. name 4 contents of the gastric juice stimulates the pancreas to release pancreatic 39. state 3 functions of bile
of food is altered hydrochloric acid, pepsinogen, rennin, mucus juice into the duodenum and the gall blader to  neutralize acidic chyme from the stomach
4. state 3 functions of the mucus found in the walls of the 18. name the cells which secrete the following release bile through the bile duct  provides suitable alkaline medium...
alimentary canal (a) hydrochloric acid  it stimulates hormone cholecystokinin which  carries out emulsification of lipids thus enhances
 lubricates food for ease of movement down the parietal cells stimulates the liver to secrete bile and the lipids digestion
gut (b) rennin pancreas to release sodium hydrogen carbonate 40. state 2 roles of the Brunner’s glands
 prevents corrosion of the stomach walls by peptic/chief cells 29. where is hormones cholecystokinin and secretin  Secrete an alkaline fluid which neutralize acidic
hydrochloric acid (c) mucus secreted chyme and provides suitable alkaline...
 prevents autodigestion by digestive enzymes goblet cells duodenal walls  Secretes mucus which lubricates duodenal walls
5. state 2 sources of enzymes that carry out digestion (d) pepsinogen 30. list 5 contents of the pancreatic juice for easy peristalsis
 from glands in the digestive system e.g. from peptic/chief cells pancreatic amylase, pancreatic lipase, trypsinogen, 41. Name the enzymes that complete the process of
gastric glands 19. state the functional difference between rennin and chymotrypsin, carboxypeptidase, sodium hydrogen digestion
 from accessory glands e.g. liver pepsin carbonate, nucleases Intestinal enzymes
6. define accessory glands and give 3 examples rennin performs coagulation of milk while pepsin 31. state the functions of the following contents of the 42. Name 2 parts of the gut where crypts of Lieberkühn are
these are glands found outside the digestive system breaks down proteins to peptides pancreatic juice found
but secrete enzymes used in digestion e.g. liver 20. write an equation to show pepsins action on proteins (a) pancreatic lipase Duodenum, ileum
pancreases, salivary glands hydrolysis  breaks down lipids into fatty acids and glycerol in 43. Name the glands that secrete intestinal juice (succus
7. define mastication and give 2 of its roles proteins peptides presence of bile salts entericus)
it refers to the physical breakdown of food by pepsin (b) pancreatic amylase Crypts of Lieberkühn glands
action of teeth 21. give a reason why pepsin is secreted in its inactive  breaks down starch which was not broken down in 44. State the effect of arrival of chyme in the ileum
it increases the S.A for enzyme action form the mouth into maltose Stimulates the secretion of intestinal juice
it makes food easy to swallow to prevent digestion of the proteins, present in cells (c) trypsin 45. Name the enzymes present in intestinal juice
8. state the role of the tongue in digestion in which they are produced i.e. autodigestion  activates chymotrypsinogen into chymotrypsin Maltase, lactase sucrase, peptidase, polypeptidase,
it manipulates food by mixing it with saliva 22. what is coagulation and state 2 of its importances  breaks down proteins into peptides pancreatic lipase, nucleotidase,
9. state 2 roles of saliva in digestion it refers to process of converting soluble milk 46. What is the other name sucrase
 activates procarboxypeptidase to carboxypeptidase
 provides suitable neutral or slightly alkaline caseinogen to insoluble casein Invertase
(d) chymotrypsin
medium for enzyme action  pepsin can only act on milk when it is in casein 47. Name the digestive juice secreted in the mouth
 breaks down proteins and polypeptides into small
 contains water that softens food form Saliva
peptides
 contains enzyme ptyalin which breakdown starch  when milk is in casein form its stays longer in the (e) Carboxypeptidase 48. State the functions of the following intestinal enzymes
to maltose stomach thus more time for digestion  Breaks down some peptides into amino acids (a) Maltase
23. state the 2 roles of the mucus present in the stomach Breaksdown maltose to glucose
 lubricates food for easy swallowing (f) sodium hydrogen carbonate
 it prevents corrosion of the stomach walls by HCl (b) Sucsrase/invertase
10. name 2 digestive enzymes found in the mouth  neutralizes acidic chyme from the stomach
ptyalin/diastase/salivary amylase, lysozyme, lingual  it prevents autodigestion by enzymes Breaksdown sucrose to glucose and fructose
 makes the contents of the duodenum slightly
lipase 24. state 4 roles of hydrochloric acid present in the (c) Lactase
alkaline thus optimum pH conditions for the
11. name the types of salivary glands and their location stomach Breaksdwon lactose to glucose and galactose
action of pancreatic and intestinal enzymes
 parotid gland- found in the cheeks infront of the  activates pepsinogen to pepsin (g) nucleases (d) Peptidase
ears  kills bacteria present in food  breaks down RNA and DNA into nucleotides
Breaksdown peptides to amino acids
 sub-mandibular gland- found under the jaw  begins hydrolysis of sucrose (e) Pancreatic lipase
32. name were enzyme enterokinase is produced and state
 provides suitable pH conditions of 1.5-2.5 for Breaks down lipids to glycerol and fatty acids
 sublingual gland- found beneath the tongue its functions
action of enzyme pepsin (f) Nucleotidase
12. define the term peristalsis it is secreted by the cells of the duodenal walls; they
 breaks down nucleotides into nucleoproteins and Breaks down nucleotides into their constituents
it refers to the involuntary propulsion of food down activate trypsinogen to trypsin
nucleic acids (g) Polypeptidase
the gut due to the rhythmic contraction and 33. state the role of bile salts in digestion
relaxation of the longitudinal and circular muscles  denatures proteins and softens fibrous breaks down large fat droplets into small droplets; Breaskdown polypeptides into peptides
found in the walls of the gut connective tissues in food emulsification 49. Name 3 constitutes of nucleotides
25. describe the cause the heartburn Pentose sugar, nitrogen base, phosphoric acid
50. Define chyle chlorine 77. State and explain the relationship between ruminants A, D, B12 ,
It refers to the resulting water emulsion after 68. State 4 functions of water in the body and the bacteria in the caecum and appendix Iron, copper, calcium
digestion in the ileum consisting of soluble end  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
products of digestion ready to be absorbed occur cellulase secreted by the bacteria while the bacteria it will lead to lack of fat-soluble vitamins in the body
51. Define the term absorption  Serves as a solvent in which materials are benefits from shelter and nutrition due to poor absorption as their absorption is
52. Name 4 substances that are absorbed in the stomach transported in the body 78. Carnivores do not grind food but instead cut them into dependent on bile
Some water, medicine, alcohol, vitamins  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
53. Name 2 fat soluble vitamins vaporization The flesh they eat do not have tough cellulose walls  calcium
Vitamin A, D, E, K  Takes part in chemical reactions such as hydrolysis thus mechanical digestion is not very important  formation of bone
54. Name 2 water soluble vitamins 69. Name the main carbohydrate present in the dietary 79. Carnivores eat less food and spend less time feeding.  necessary for muscle contraction
Vitamin B, C fibre Explain  necessary for blood clotting
55. State the role of bile in digestion Cellulose This is because most of their food they eat is digested  phosphorus
Enhances absorption of fat-soluble vitamins 70. Explain why dietary fibre has no nutritional value in and absorbed  formation of bone and teeth
56. Define defaecation man 80. Describe the adaptations of rumen to their functions  potassium
It refers to the process by which rectum muscles Dietary fibre mainly contains cellulose and man does  Highly folded to provide large surface area for  transmission of nerve impulses
contract pushing out indigestible food substances out not secret enzyme cellulase to digest it absorption  zinc
through the anus 71. Define constipation  Has numerous villi to increase the surface area  necessary for the proper functioning of many
57. State the role of the bacteria and protozoa present in It refers to the difficulty in removal of undigested for absorption enzymes as well as taste buds and smell
the large intestine food materials from the body through the anus 81. Explain why rabbits and rodents ingest their feaces receptors
They feed on undigested food materials 72. Explain how dietary fibre prevents constipation Because there is very little absorption of products of  sodium
58. State the effects of the bacteria and protozoa present in  It enhances peristalsis fermentation  maintenance of osmotic pressure of body
the large intestine 82. List 4 stomachs of an herbivore
 It absorbs water from the alimentary canal thus fluids
Results in the synthesis of vitamins such as vitamin K  Rumen  transmission of nerve impulses
making faeces moist hence easy movement
Leads to formation of gases like carbon IV oxide,  Reticulum
73. Explain how roughage enhances peristalsis  iron
methane and hydrogen sulphide  Omasum
It adds bulk to food thus creating a grip for the gut  formation of haemoglobin in body cells
59. Name 2 vitamins synthesized by microorganisms in the  Abomasum
muscles enhancing peristalsis  copper
large intestine 83. Give a reason why the epiglottis closes the windpipe
74. State 2 main functions of energy in the human body  necessary for proper utilization of iron
Vitamin K, B12 during swallowing
Mechanical work  necessary for some enzymes to act
60. State the fate of glucose that is carried to the liver To prevent choking by preventing the entry of food
Basal metabolism  manganese
 It is respired 75. What is basal metabolism rate into the trachea  necessary for proper functioning of many cells
 It is converted to glycogen and stored It refers to the minimum amount of energy required 84. State 3 reasons why the small intestine is highly folded  iodine
61. State the use of absorbed amino acids in the body to drive vital life processes such as blood circulation,  To fit into the small abdominal cavity  formation of thyroid hormones
They are used by the body cells to form proteins breathing, active transport, thermoregulation  To slow down the movement of food thus giving
62. What happens to excess amino acids in the body  cobalt
76. Explain 6 factors that affecting energy requirements in enough time for digestion and absorption  a constituent of vitamin B12
They are deaminated man  To provide a large surface area over which 95. Name 2 minerals whose deficiency causes anaemia
63. What happens to the residual compound after  Basal metabolism rate- this is the minimum amount digestion and absorption of food occurs Iron, cobalt
deamination of energy required to drive vital life processes such 85. Give a reason why bile is alkaline
It is converted to glucose and respired 96. How is the enamel adapted to its function
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
64. State the fate of absorbed vitamins and minerals such thermoregulation. A person at rest requires energy carbonate follow
as iron, calcium to drive this processes 86. State the role of enzyme enterokinase
They are stored in the liver and released to the body
 Occupation- manual workers requires more energy It activates trypsinogen to trypsin
according to its needs
than sedentary workers 87. Explain why digestion of starch stops in the stomach
65. State the role of vitamins in the body
 Age- young people require more energy since they Starch is digested into maltose by ptyalin which works
They are responsible for proper growth and best under neutral/slightly alkaline conditions. Thus,
are growing and hence have many actively dividing
development proper body functioning and the acidic conditions in the stomach denatures ptyalin
cells
maintenance of metabolic processes in the body
 Body size- small sized people require more energy as 88. State 3 factors that make the duodenum alkaline
66. Different between macro/bulk nutrients and micro/
they have a larger surface area to volume ratio  Bile salts containing sodium hydrogen carbonate
trace nutrients
hence more heat is lost to the surrounding thus  alkaline fluid secreted by the Brunner’s glands
Macronutrients refers to nutrients which are required
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
the surrounding are low more energy is required in 91. state 2 ways of preventing constipation
Calcium Iodine
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
fight pathogens. Also lactating mothers require 92. give examples of vitamins and mineral salts stored in
Phosphorus Cobalt
more energy for breast feeding the liver
Sulphur zinc
 being chewed by cheek teeth and grass that is attacks teeth causing demineralization and eventual
newly gathered by front teeth. destruction of the enamel. This leads to dental caries.
 (iii) Its premolars and molars have a large top In addition, the acid attacks and destroys the gums
surface which is worn out unevenly forming cusps and the periodontal membranes leading to gum
which help in crushing and grinding of vegetation. disease
 (iv) The joints of the jawbones are loose allowing 103. Describe the digestion of proteins in the alimentary
up and down as well as sideways movements of the canal of an adult human being
lower jaw which aids in the grinding process.
Digestion of proteins begins in the stomach where the
 (v) Its rumen contains microorganisms that
enzyme pepsin breaks down proteins to polypeptides. In the
ferment cellulose releasing simple fatty acids that
small intestine, the pancreatic enzymes, trypsin and
are absorbed by the animal.
chymotrypsin break down polypeptides and proteins to
 (vi) The abomasum or true stomach and the small peptides. The intestinal enzyme, called peptidase, completes
intestine have a large variety of enzymes that digest the digestion of proteins by breaking peptides to amino
(a) Name the structure above proteins, carbohydrates and fats to soluble acids
Villus molecules that can be absorbed.  Giving your reasons, state whether this villus comes
(b) What is the function of the part the part labelled E  (b) The dog has the following carnivorous 104. What is the role of HCl in protein digestion? from the duodenum or ileum.
Crypt of Lieberkühn adaptations:  It converts pepsinogen to pepsin  It comes from the ileum as evidenced by the
(c) Giving your reasons sate whether the villus is from  (i) It has well-developed leg muscles that enable it  It provides an acid pH (pH 1.5 - 2.5) which is the absence of Brunner's glands.
the ileum or the duodenum to run swiftly after its prey. optimum pH for action of pepsin  What is the function of the part labelled E?
Duodenum; presence of Brunner’s glands  (ii) It has a strong sense of smell and sight which  It unfolds (denatures) proteins enabling pepsin to  Secretion of intestinal enzymes
(d) Name the labelled parts are important in hunting. work on them. 108. (a) Describe the absorption of digested food in
A- Microvillus  (iii) It has chisel-shaped incisors that fit closely 105. State any three functions of the mucus which is mammals.
B- Lacteal enabling it to grip and tear off pieces of flesh close secreted along the wall of the alimentary canal
C- Vein to the bone.  (i) It lubricates food (b) Name two nutrients that are absorbed in the mammalian
D- Artery  (iv) It has long, curved and pointed canines which  (ii) It prevents digestion of the gut wall by gut without chemical digestion.
E- Crypt of Lieberkühn are used for piercing the prey, preventing its escape proteolytic enzymes.  (a) The soluble products of digestion are absorbed
F- Brunner’s gland and often killing it.  (iii) It makes food particles to adhere to one in the small intestine especially in the ileum.
G- Arteriole  (v) It has carnassial teeth (upper fourth premolar another during swallowing and during egestion. Monosaccharides, amino acids, vitamins and
H- Capillary network and the lower first molar) which are large and 106. What triggers the secretion of gastric juice? inorganic ions are transported across the epithelial
I- Lymphatic system powerful. They overlap like the blades of scissors
(i) The hormone gastrin which is secreted into the lining by a combination of diffusion and active
J- Epithelial cell and are used for shearing and slicing flesh,
bloodstream by certain cells of the stomach in response to transport into the capillaries of the villi. Fatty acids
K- Goblet cell tendons and skin.
the presence of food in the stomach and glycerol are absorbed into the epithelial cells
98. What is balanced diet  (vi) The other premolars and molars have jagged of the villi and here they are re-assembled into
It refers to a diet containing adequate amount of edges that fit perfectly together making them ideal (ii) Sight, thought, taste or smell of food. neutral fats. The fats are then shed into the lacteals
carbohydrates, fats, proteins, vitamins and inorganic for cracking bones. which shed their contents into the lymphatic vessels
ions 101. Explain the role of the following organs in the Mode of Exampl
Skull Special features and thence into the bloodstream.
99. What disease is caused by deficiency of the following digestion of food in a mammal:(a) Salivary glands (b) feeding e  (b) Vitamins and inorganic ions.
(a) Vitamin niacin/Nicotinamide Pancreas (c) Liver. 109. (a) What is a balanced diet?
pellagra  (a) They produce saliva. Saliva contains the Absence of incisors and canines
(b) Iodine enzyme salivary amylase (ptyalin) which begins the A Herbivorous on upper jaw Presence of aSheep (b) Which components of a balanced diet are not nutrients and
Goitre digestion of starch breaking it to maltose. It also diastema why are they required?
(c) Vitamin B2/Riboflavin lubricates food making it suitable for swallowing.
Ariboflavinosis  (b) It produces pancreatic juice. This contains Presence of long, curved and (c)For each of the diseases in column A choose the matching
(d) Thiamine sodium hydrogen carbonate (NaHCO3) and several B Carnivorous sharp canines Presence ofDog cause in column B.
Beriberi enzymes. NaHCO3 neutralizes the acid of chyme carnassial teeth
(e) Vitamin D and creates a pH of 7-8 which is the optimum pH COLUMN A COLUMN B
Rickets for the action of pancreatic and intestinal enzymes. 107. The figure below is a diagram of an intestinal villus.
(f) Calciferol (1) Obesity (a) Deficiency of vitamin C
Enzymes present in pancreatic juice are:
Osteomalacial (in adults)  ·Trypsin which digests proteins to peptides. (2) Kwashiorkor
100. Give an account of the adaptations of (a) a named  ·Amylase which digests starch to maltose (b)Deficiency of the vitamin niacin
herbivore and (b) a named carnivore to its mode of (children)
 ·Lipase which digests fats to fatty acids and
feeding. glycerol. (3) Goitre (c) Deficiency of vitamin D
 (a) A sheep has the following herbivorous  (c) it produces bile. Bile salts carry out
adaptations: emulsification. This increases the surface area of (d) Deficiency of vitamin B1
 (i) It has a thick horny pad on the upper jaw over the fat enhancing the action of pancreatic lipase. (4) Anaemia
(thiamine)
which vegetation is pressed by chisel-like incisors 102. Why is eating a lot of sugary foods harmful to the
and canines on the lower jaw during feeding. teeth? (5) Night blindness (e) Deficiency of iron
 (ii) It has a diastema which provides space for Sugar in the diet is fermented by bacteria in the
tongue movements that separate grass which is mouth leading to the formation of acid. The acid
(6) Beriberi (f) Deficiency of proteins xylose 0.30 0.31 (b) If they were secreted in an active form. they would (a)A parasite is an organism that lives in or on another
digest the cells in which they are formed and the lining of organism and obtains from its nutrients and sometimes
(7) Pellagra (g) Excess carbohydrates and fats arabinose 0.29 0.29 the glands that secrete them. shelter.

(8) Scurvy (h)Deficiency of iodine 111. Comment on these results. 116. (a) Describe the role of the rumen in ruminants. (b) Ectoparasites are those parasites that live on the
surface of their host's body. Examples are lice and ticks.
Glucose and galactose are absorbed by both active transport (b) How do non-ruminant herbivores make use of cellulose? Endoparasites are those parasites that live inside their
(9) Osteomalacia (adults)(i) Deficiency of vitamin A and diffusion. Fructose is absorbed by diffusion with active
 (a) It contains cellulase-producing microorganisms host's body. Examples are tapeworms and Trypanosomes.
transport only playing a minor role. Xylose and arabinose
(a) A balanced diet is one that contains adequate amounts of that ferment cellulose to simple fatty acids. These
are absorbed by diffusion only. (c)A primary host, also called a definitive host is the
carbohydrates, fats, proteins, inorganic ions. vitamins, water are absorbed through the rumen wall and carried
and roughage to meet the body's needs. Too much or too organism that harbors the adult stage of a parasite. An
112. In what ways is the mammalian small intestine by the bloodstream to various tissues where they
little of any of these substances causes a nutritional intermediate host, also called a secondary host is the
adapted for its functions? are used for respiration. The microorganisms also
imbalance leading to malnutrition. organism that harbors the larval stage of a parasite.
 ·It is long and the inner lining is highly folded manufacture microbial proteins. Upon the death of
(b) The non-nutrient components of a balanced diet are offering a large surface area for the digestion and the microorganisms which occurs in the 7.2 (a) Symbiosis is a physical association between two
water and roughage. Water intake is necessary to absorption of food. abomasum. the microbial proteins are broken down different organisms whereby both benefit from the
compensate for loses through sweat. urine, faeces, and to amino acids and absorbed into the ruminant's relationship.
expiration in order to maintain a relatively constant volume  ·Its inner wall has villi and microvilli, which
increase further the surface area for absorption bloodstream.
of the various body fluids. (b) (i) Ruminal microorganisms secrete the enzyme
 (b) Non-ruminant herbivores contain cellulase-
 ·It has openings through which the pancreatic and cellulase which breaks down cellulose from plant materials
Roughage provides bulk to the intestinal contents especially producing microorganisms in the caecum. These
in the large intestine. This stretches the intestine, stimulating bile ducts open. absorbed in the colon and carried by the to glucose. The microorganisms ferment the glucose to
reflex peristaltic activity which helps in the movement of  ·It has goblet cells and Brunner's glands that bloodstream to other tissues where they are used simple fatty acids. These are absorbed into the ruminant's
indigestible matter towards the rectum. In absence of secrete mucus for lubrication and protection of the for Instead. They ingest their faeceswhich are bloodstream and carried to the tissues where they are
roughage. peristaltic movements are very slow or absent wall from digestive enzymes. subjected to further digestion and absorption in the oxidized for energy production. The presence of such
leading to constipation. microorganisms enables ruminants to utilize a wide variety
 ·The Brunner's glands also secrete an alkaline stomach and small intestine.
fluid which maintains a pH of 7-8 which is the of plant materials as a source of food. The bacteria are in
(c)(1)g:(2) f;(3)h;(4)e;(5)i;(6)d;(7)b;(8)a;(9)c
turn sheltered in a nourishing medium.
optimum pH for action of intestinal enzymes
6.13 Explain the term phagocytic nutrition using a relevant
example.  ·It has intestinal glands that secrete digestive PARASITISM,SYMBIOSIS AND SAPROPHYTISM (ii) The protozoa Triconympha are found in large numbers
enzymes in the alimentary canal of worker termites. They secrete the
Phagocytic nutrition is a process through which cells take in  (a) What is a parasite? enzyme cellulase which digests cellulose from plant
 ·It has a rich vascular network that supplies oxygen  (b) Differentiate between ectoparasites and
solid food material and digest it intracellularly. It is carried materials to glucose. Some of the glucose is absorbed and
out by protozoa such as Amoeba. and removes digested food endoparasites. In each case give two examples.
 ·The walls have muscles whose peristaltic used by the termite. The presence of such protozoa enables
 (c) With reference to parasites, explain the terms termites to feed on wood materials. The protozoa are in
Once an Amoeba comes into contact with solid food contractions causes movement of food in the gut
material, it sends out finger-like projections called primary host and intermediate host. turn sheltered in a nourishing medium.
pseudopodia. These surround the food material forming a and mixing of food with digestive enzymes  7.2 (a) Define the term symbiosis
food vacuole. The vacuolar membrane pinches off from the  ·The villi have a thin epithelium that allows soluble  (b) What are the benefits of the following (iii) Bacteria of the genus Rhizobium invade the roots of
plasma membrane and the vacuole migrates to the centre of food materials to pass through easily associations? young leguminous plants and cause the root cells to
the cytoplasm. The vacuole fuses with one or more lysosomes  ·The villi have numerous blood vessels to transport  (i) Ruminants and ruminal microorganisms. multiply forming nodules. In the nodules, the bacteria fix
which discharge digestive enzymes into it. These proceed to  (ii) Worker termites and the protozoa Triconympha. atmospheric nitrogen into ammonia. The ammonia is used
absorbed nutrients and lacteals to transport
digest the contents of the vacuole. The soluble products of  (iii) Bacteria of the genus Rhizobium and by both the bacteria and the plant to make amino acids.
digestion, e.g. Monosaccharides and amino acids diffuse absorbed lipids
leguminous plants. The bacteria in return receive carbohydrates from the
through the vacuolar membrane and get into the cytoplasm. 113. Name one nutrient that is only transported in small
 (iv) Mycorrhizal fungi and forest trees. plant. This association enables leguminous plants to grow
Indigestible materials are expelled by a reversal of the quantities in the hepatic portal vein following
mechanism of food vacuole formation, i.e. the vacuole moves  7.3 List five ways in which the pork tapeworm in soils that are poor in nitrates. When the plants die, the
absorption (Taenia solium) is adapted to life in human nodules release ammonia into the soil where it is converted
to the surface and fuses with the cell membrane discharging  Fats
indigestible materials to the outside. alimentary canal. to nitrates by nitrifying bacteria. The nitrates can be taken
114. Why is it necessary that blood from the digestive  7.4 Name the diseases caused by: (a) Ascaris up by other plants.
110. The table below shows the results of experiments on tract pass through the liver before entering the general lumbricoides (b) Wuchereria bancrofti (c)
the rate of absorption of various monosaccharides by circulation? Plasmodium vivax (d) Trypanosoma gambiensis (c) (iv) Mycorrhizal fungi invade the roots of certain species of
pieces of living intestines and by pieces of intestines forest trees forming a root-fungus complex called
poisoned with cyanide. The rates are given as relative to The liver helps to regulate the level of nutrients entering Phytophthora infestans.
 7.5 Explain the importance of adjustment of a mycorrhiza. The fungi are able to absorb essential
the rate of glucose absorption by living intestine the general circulation in such a way that they are nutrients like calcium,phosphate,potassium and other ions
relatively constant immediately after meals and during parasite to its host.
Rate of absorption  7.6 Explain how fungi that are parasitic to plants from the soil better than the trees. Some of the nutrients
fasting. are used by the fungus and the rest are passed to the tree.
Sugar feed.
By living intestine By poisoned intestine 115. The enzymes pepsin and trypsin are secreted as  7.7 Explain how the fungi Rhizopus feeds. The fungus in return gets organic materials that are
inactive precursors:  7.8 Describe the ecological importance of manufactured by the tree through photosynthesis. This
glucose 1.00 0.33 saprophytes. enables such trees to survive in areas where soils are
(a)What are the names of the precursors? (b) Why are they  7.9 (a) State two similarities in the modes of relatively poor in mineral salts.
galactose 1.10 0.53 secreted in an inactive form? nutrition of Rhizopus and tapeworms. 7.3 (i) It has suckers and hooks on its head for attachment
fructose 0.43 0.37 Pepsinogen and trypsinogen.  (b) State two differences in their modes of nutrition. to the intestinal wall of its host.
(ii) It has a flattened body that offers a large surface area (b) (i) Rhizopus produces the enzymes responsible for
for absorption of soluble nutrients across the body wall. digesting the food outside its body. While tapeworms rely
on the host's enzymes to digest the food.
(iii) It secretes a lot of mucus and anti-enzyme substances
that protects it from the digestive action of the host's (i) Rhizopus obtains its food from dead materials while
enzymes. tapeworms obtain their food from living organisms.
(iv) Each worm produces millions of eggs that remain MICROORGANISMS
infective for long periods of time ensuring successful
transmission to the next host. 116. To what structure in higher animals and plants does
the nucleus correspond? What is their main similarity
(v) It can respire anaerobically, enabling it to survive the and their main difference?
low oxygen content of the human's gut. (vi) It is a
hermaphrodite, which makes reproduction easier. It corresponds to the nucleus. They are similar in that both
carry the genetic material of the cell. They differ in that;
7.4 (a) Ascariasis (b) Elephantiasis (c) Malaria (d) the nucleus is enclosed by a membrane while the nuclear
Sleeping sickness (e) Potato blight. body is not.
7.5 Adjustment of a parasite to its host ensures that a 117. List three ways in which a bacterial cell differs from
parasite continues deriving nutrients and some-times an animal cell.
shelter from the host while inflicting minimum damage.  A bacterial cell has a cell wall which is absent in
This is important to the parasite in that it has time to grow, an animal cell.
reproduce and spread. A poorly adjusted parasite normally  ·In bacteria the nuclear material is not enclosed by
kills its host quickly. In the process the parasite may a nuclear membrane.
damage itself or lose its source of food.  ·A bacterial cell has no membrane bound
organelles like mitochondria and endoplasmic
7.6 The tips of some of their hyphae produce the enzyme
reticulum.
cellulase. This digests the cellulose wall of host cells
118. Give an explanation for the following observations:
enabling the hyphae to penetrate. Once inside, each hypha
 (a) A piece of meat placed in the open rots within
swells into a haustorium. This secretes enzymes that digest
several hours while a similar piece placed in a deep
complex organic materials in the cell. The soluble products
freezer stays fresh for several months.
of digestion are absorbed into the cytoplasm of the fungi.
 (b)A piece of moist bread placed in the open
7.7 The tips of hyphae that grow into the food source develops a greyish-black growth on its surface while
secrete enzymes. The enzymes soak into the dead material a piece of dry bread under similar conditions
and proceed to digest its constituents into simpler remains fresh.
compounds. Proteins are digested to amino acids,  (c)Sealed pasteurized milk placed at room
carbohydrates to monosaccharides and fats to fatty acids temperature will go bad within one day while sealed
and glycerol. The amino acids, monosaccharides, fatty UHT (ultra heat-treated) milk remains fresh for a
acids and glycerol are absorbed into the cytoplasm of the long period of time at room temperature.
fungi.  (a)Meat provides a very good medium for the
growth of bacteria. When a piece of meat is placed
7.8 Saprophytic bacteria and fungi that live in the soil and in the open, microorganisms from the air land on it
water bring about decay of dead animals and plants. The and multiply. They release enzymes that proceed to
organic materials in the dead bodies are eventually broken digest complex organic compounds in the meat into
down to simple inorganic compounds such as carbon simpler compounds causing decay. The process is
dioxide, ammonia and mineral salts. These are taken up by also aided by enzymes that are naturally present in
plants and used to make new organic compounds. This the meat.
way, saprophytes help in the recycling of nutrients in  When meat is placed in a deep freezer, the low
nature. Were it not for their action of breaking down dead temperature inhibits multiplication of any bacteria
materials, essential nutrients would be locked in huge that may be present. The low temperature also
moulds of dead animals, faeces, leaves, branches and logs inhibits the action of bacterial enzymes as well the
which would be littered all over. The nutrients would be action of enzymes naturally present in the meat.
unavailable to subsequent generations of plants and Because of these reasons, the meat can remain
animals and life as we know it would cease. fresh for a long time.
7.9 (a) (i) Both are heterotrophic taking in ready-made  (b) Bread provides a very good medium for the
food. growth of moulds. When a piece of bread is kept in
the open, mound spores land on it from the air.
(ii)Both never ingest their food but absorb soluble nutrients However. for the spores to germinate, moisture
from the surrounding medium. must be present. Moist bread contains the
necessary moisture and the spores germinate each
developing into a greyish mycelium or hyphae.