GELAN BOY’S PREPARATORY AND SECONDARY

SCHOOL
BIOLOGY HANDOUT
GRADE 9

By Nurye Belachew 2015

 TABLE OF CONTENTS

UNIT 1..........................................................................................................................................3
BIOLOGY AND TECHNOLOGY............................................................................................3
1.1... RENOWNED ETHIOPIAN BIOLOGISTS..................................................................3
1.2BIOLOGICAL RESEARCH IN ETHIOPIA.....................................................................4
UNIT 2..........................................................................................................................................5
CELL BIOLOGY........................................................................................................................5
2.1. THE MICROSCOPE......................................................................................................5
2.2. THE CELL.....................................................................................................................6
2.3. THE CELL AND ITS ENVIRONMENT......................................................................9
UNIT 3........................................................................................................................................12
HUMAN BIOLOGY AND HEALTHY..................................................................................12
3.1. FOOD AND NUTRITION...........................................................................................12
3.2DIGESTIVE SYSTEM....................................................................................................18
3.3. RESPIRATORY SYSTEMS.......................................................................................22
3.4. CELLULAR RESPIRATION......................................................................................24
3.5. CIRICULATORY SYSTEM.......................................................................................26
UNIT 4........................................................................................................................................32
MICRO-ORGANISM AND DISEASE...................................................................................32
1.4. MICRO-ORGANISM..................................................................................................32
2.4. DISEASES...................................................................................................................36
UNIT 5........................................................................................................................................43
CLASSIFICATION..................................................................................................................43
5.1. PRINCIPLES OF CLASSIFICATION........................................................................43
5.2. THE FIVE KINGDOM................................................................................................44
UNIT 6........................................................................................................................................52
ENVIRONMENT......................................................................................................................52
5.3. ECOSYSTEMS............................................................................................................52
5.4. FOOD RELATIONSHIP.............................................................................................52
5.5. RECYCLING IN NATURE.........................................................................................55
5.6. ADAPTATIONS..........................................................................................................56

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 Unit 1
BIOLOGY AND TECHNOLOGY

RENOWNED ETHIOPIAN BIOLOGISTS

 Biology is the study of life and living organisms.

 Biologists study both the outer appearance and the internal workings of living things.
 All biological knowledge comes by the work of biologists, scientists who study living
organisms.
 Hypothesis an idea or statement that explains observed facts and predicts new
outcomes
 Journal a regular publication presenting articles on a particular subject
 Peer review evaluation of a person’s work done by others in the same field
 Some of the most important renowned Ethiopia biologists are listed below;
1) Dr Aklilu Lemma and the battle against bilharzias (schistosomiasis)
 Discover endod that can kill snail (secondary host of blood fluke)
2) Dr Tewolde Berhan Gebre Egziabher, an ardent lover of nature
 Safeguard biodiversity and genetic resource
 environmental protection and diversity
3) Professor Tilahun Yilma and his vaccines
 Develop vaccine to get rid of cattle disease called rinderpest.
 Work on HIV/AIDS vaccines using genetic engineering
4) Professor Yalemtsehay Mekonnen: the first female professor in AAU
 Worked the assessment of the impact of chemical pesticide hazard on humans. And
 The importance medicinal plants against human and animal diseases
5) Dr Melaku worede
 Worked to save the genetic diversity of Ethiopia’s domestic plants.
6) Dr Gebissa Ejeta
 Develop Africa’s first commercial hybrid new strain of sorghum, which is resistant to
drought.
7) Professor Legesse Negash
 Research in the conservation of indigenous plant propagation and biodiversity
development in Ethiopia
8) Professor Beyene Petros
 A biomedical scientist and long serving professor at Addis Ababa University
9) Dr Zeresenay Alemseged
 Discovered 3.3 million-year-old human old child fossil in 2006.

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10) Dr Tsehaynesh Meselle
 Director General of the Ethiopian Health and Nutrition Research Institute (EHNRI)
11) Dr Berhane Asfaw
 An Ethiopian scientist whose team discovered two 160 000-year-old human skulls

12) Professor Mogessie Ashenafi

 Works at the University of Addis Ababa and leads international research into food
microbiology.

13) Professor Ensermu Kelbessa

 Is one of the leading systematic botanists who has discovered and named many new
plant

BIOLOGICAL RESEARCH IN ETHIOPIA

 Some of the institutions that play an important part in biological research in Ethiopia;

1) Addis Ababa University (AAU) Biology Department

 Mainly involved in;
 Food quality and quantity improvement
 Conservation of natural resources
 Disease and vector control
2) Armauer Hansen Research institute (AHRI)
 AHRI was first set up in 1969, carried out research only into leprosy.
 However, since 1996 AHRI has widened its research into tuberculosis (TB),
leishmaniasis, malaria and HIV/AIDS, as well as leprosy.

3) Aklilu Lemma institute of Pathobiology (ALiPB)

 ALIPB carries out research in five major areas;.
 Major infectious diseases,
 Vectors of diseases and how to control them,
 Human parasitic diseases
 Animal health and disease.
 Research on Endod and other plants as source of medicine

4) Ethiopian institute of Agricultural Research (EiAR) also known as.

Institute of Agricultural Research (iAR)
 There are five main areas of research.
 working on crop technology have improved crops like maize, teff and sorghum
 improving the health of livestock
 improving the fertility of the soil
 Forestry
 mechanizing farming

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5) The Institute of Biodiversity Conservation (IBC)
 Biodiversity – the verities of living organisms in an area.
Mainly involved in;
 The conservation of plants, animals and micro-organisms in Ethiopia.
 Research into the management of the ecosystem such as
 Forest and aquatic plants
 medicinal plants
 animal genetic resources
 biotechnology and safety,
 Ecosystem conservation.
 It holds one gene banks in the whole of Africa with over 300 plant species
 Preservations of gene of Ethiopian domestic plant.

UNIT 2
CELL BIOLOGY

2.1. THE MICROSCOPE

 Is an instrument that helps to observe very small organisms, cell and their cell components
Two major ability of microscope
 Magnification
 Increase the size of an object
 The best light microscope magnify up to 2000 times
 An electron microscope magnify up to 2 000 000 times
 Resolution
 The ability to distinguish between two separate points
 The measure of how much detail the microscope can show is called resolving power
 The greater the resolving power of the microscope, the more detail it can show
 The resolving power and the wave length are inversely proportional
 The higher the wave length the smaller resolving power
 The electron microscope has higher resoling power then light microscope

Type of microscope
1) Light microscope
 Use a beam of light to form an image
 Relatively less magnification and resolution power
 Due to its low resolution power light microscope is not used to see cellular organelle such as
ribosome, mitochondria, chloroplast, endoplasmic reticulum

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  Used to study cell, tissues or individual organism
 Used to study living material directly through light microscope
 Mounting and staining is the basic techniques using the light microscope
 Mounting is a techniques of preparing an object or specimen to be seen under microscope
 Staining is a method of adding pigment chemicals to slid tissue to make cells or their parts
easier to see.

Type of stain Type of cell Main organelles stained

 Haematoxyli  Animal and plant  Nuclei stained blue/ purple
ne cell or brown
 Methylene  Animal cell  Nuclei stained blue
blue
 Acetocerami  Animal and plant  Staining the chromosomes
ne cell
 Iodine  plant cell  Any material Containing
starch
 Total magnification of light microscope is the product of an eye piece / ocular/ and objective
lens
Total magnification= magnification power of × magnification
power Eye piece of objective lens

Advantage of light microscope

 It help to study living things
 It is relatively cheap
 Easy to move from place to place
 Do depend on electric source
Disadvantage of light microscope
 It has limited magnification and resolution power
2) The Electron microscope
 Use a beam of electron
 It has highest magnification and resolution power
 Its maximum magnification power is 2,000,000
 Resolving power of an electron microscope is 1000 times greater than the resolving
power of light microscope

 Advantage of electron microscope

 It has high magnification and resolution power
 Used to see three dimensional structure of specimen e.g. .scanning electron microscope
 Transmission electron microscope used to show the detail structure of microscope
 Disadvantage electron of microscope
 Do not use to study living things
 It very expensive
 Depend on electric source
 It is not easy to move from place to place

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 2.2. THE CELL

 All living organisms are made unit called Cell

 Cell are the basic structural and functional units in all living organism
 Some organisms like bacteria and protozoa are composed of a single cell and are called
unicellular organism
 Plant, animal, fungi composed of many cell are called multicellualar organism
 There are seven lifer process that are common to most living things
1. Nutrition; food substance need by the body
2. Respiration; the process by which living organism get the energy from the food we eat
3. Excretion; getting rid metabolic west product produced by cell
4. Growth; increase the size and mass of an organism
5. Irritability; sensitivity of an organism to changes in an organism
6. Movement; the need to get near to or away from things
7. Reproduction; the production of offspring to ensure the survival of a type of organism
 Cell theory
 Cell were first by discovered by English scientist called Robert Hook
 Matthias Schledian and Theondoer Schwann introduce the idea of cell theory
 Cell theory states that cell are the basic unit of life

Type of cell
 Prokaryotic cell
 Eukaryotic cell
Prokaryotic cells
 Smaller cells
 Smaller ribosomes
 Lack distinct nuclei and membrane bounded organelle
 Nuclear material not enclosed by membrane
 No membrane bounded cellular organelle
 Do not have chromosome because DNA do not have protein histone
 Have cell wall but chemically different from eukaryotic cell
 E.g. bacteria and blue green algae
Eukaryotic cell
 Larger cells
 Larger ribosomes
 Have true nucleus bounded by membrane
 Have many membrane bounded organelle
 Have chromosome , DNA has protein histone
 Found in all organism except bacteria and blue green algae
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 Eukaryotic cell structure and function
 Almost all eukaryotic cell have three Major parts
 Nucleus
 Cell membrane
 Cytoplasm
1) The nucleus
 Control all activities of cell
 Contains instruction for making a new cell Known as chromosome or genetic material
2) Cell membrane
 Forms a barrier between the cell and outside the cell
 Semi/ partially/selectively/ permeable membrane
 Control the movement of substance in and out of the cell
 Substance that cross the cell membrane are carbon dioxide, oxygen, water
 Made up of protein and lipid bilayer, it is called lipo-protein layer
3) The Cytoplasm
 Internal structure of the cell outside the nucleus
 A liquid gel in which in most of the chemical reaction for life take place
 The cell contain Specialized organelle to perform specific task

4) Cytoplasmic organelles
 Are membrane bounded Structure in a cell
 Examples the nucleus other organelles are found in the cytoplasm
 Specialized to perform specific task because they have specific enzymes
 Some of very important organelles are listed below;
I. Mitochondria
 The power house of the cell
 They carry out the reactions of respiration
 Energy is released from then food we eat for cellular activities
II. Endoplasmic reticulum(ER)
 Three dimensional system of tubules
 It links the nucleus with the cell membrane
 Two forms of endoplasmic reticulum

Rough ER
 Have ribosome on its membrane surface
 Involved in protein transport synthesized by ribosome

Smooth E.R
 Has no ribosome on its surface

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  Concerned with lipid synthesis, carbohydrate metabolism and detoxification
III. Ribosome
 Found on the endoplasmic reticulum and freely in the cytoplasm
 Responsible for protein synthesis

Organelle found only in plant cells

Permanent Vacuole
 It is fluid portion and central components of plant cell
 Filled with a fluid called cell sap
 help to maintains the turgidity to plant cell
Chloroplast
 Found in all green part of plant cell
 Contain the green pigment called chlorophyll
 It is the site of photosynthesis
 What are the organelles found only in Animal cells?

Cell specialization in human

 Undifferentiated cells /unspecialized cells/; cells that have not yet assumed their final
characteristics.
 Embryonic stem cell; Undifferentiated cells in the early embryo that have a potential
to form almost other type of cell
 Specialized cells /differentiated cell/; adapted to carry out a particular bodily function
 Some of specialized cell in humans are;
1) Epithelial cells; specialized to perform
 Protection
 Diffusion of material
 Secretion
 Ciliated epithelial in respiratory used to move microbe away from your lung
 Ciliated epithelial in female reproductive help to move substance toward the uterus
2) Reproductive cells (the egg and sperm)
 Egg
 Contain half the number chromosomes found in normal body cells
 Egg cell have large nucleus contain genetic information from the women
 Have a protective coat to make sure only one sperm fertilized the egg
 Sperm
 Contain half the number chromosomes found in normal body cells
 Sperm have long tails they can swim towards the egg
 The middle portion of the sperm contain mitochondria which provide energy for the
tail to wark
 They have special as known as acrosome; which store digestive enzymes used for
breaking down the outer layer of the egg.
 Have large nucleus contain genetic information
3) Nerve cell (neurons)
 Communication and control system of your body

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  Control and coordination system of the body
4) Muscle cells
 Perform movement in your body

2.3. THE CELL AND ITS ENVIRONMENT

 Exchange of between the cell and its environment takes place in the following major
ways
1. Diffusion
2. Osmosis
3. Active transport

1. Diffusion
 Is the net movement of particle from an area of higher concentration to an area of lower
concentration
 A passive movement of substance and depend on concentration gradient
 Is the random movement of gas or substance
 Diffusion occur along or toward concentration gradient
Rate of diffusion
Rate of diffusion can be affected by factors like;
 Temperature
 as the temperature rises, the rate of diffusion also increase
 Concentration gradient; the difference in concentration between two area
 The bigger the difference in concentration the faster the rate of diffusion
2. Osmosis
 Is the movement of water molecule from an area of high water concentrations to low water
concentration across semi permeable membrane
 Osmosis depend on a concentration gradient of water and a partially permeable membrane
 Is the movement of water molecule from dilute solution to concentrated solution
 There are three type of solution depending upon their concentration of solute
Isotonic solution
 The solute concentration of the cell and its surrounding environment are the same
 There is no net movement of water into and out of the cell
Hypotonic solution
 The solute concentration of surrounding the cell has less solute then the cell
 The cell gain water and swell up
Hypertonic solution
 The solute concentration outside the cell more concentrated then inside the cell
 The cell losses water by osmosis

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 Osmosis in plant and animal cell
Solution Plant cell Animal cell
 Isotonic  There is no net movement of water  There is no net movement
of water
 Hypotonic  The cell gain water and swells  The cell gain water
Dilute or  The cell becomes turgid  The cell will swell and
Weak  The cells do not burst. Because the cell eventually burst
solution wall exerts wall pressure against turgor /hemolysis/
pressure
 Hypertonic  The cell loss water by osmosis  The cell loss water by
Concentrated  The vacuole shrinks and the cell become osmosis
or strong flaccid  The cell becomes shrink
solution  The cytoplasm pulls away from cell wall and shrivel
known as plasmolysis

3. Active transport
 Allows cell to move substance from an area of low concentration to an area of high
concentration
 Substance move against concentration gradient
 Important the cell can absorb ions from dilute solutions
 Use energy from cellular respiration

 The important of active transport

 Plants can absorb mineral ion needed for making protein. Mineral ions in the soil are
usually found in a dilute solution then the plant cell
 Glucose is moved out of the gut and kidney tubule into blood

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 UNIT 3

HUMAN BIOLOGY AND HEALTHY

3.1. FOOD AND NUTRITION

 The human diet is a diet that provide all necessary class of nutrients in adequate amounts
What is food?
 Food is the source of nutrients and energy for the body.
 Three main use food in :
 To provide energy for cells
 Raw materials for growth, repair and replace damaged and worn out cells.
 To provide the resources needed to fight disease and maintain a healthy body.
 There are six main classes of food needed by the body. These are;
 Carbohydrates, macronutrients; needed in a large amounts
 Proteins
 Fats
 Minerals micronutrients ; needed in a small or tiny amounts
 Vitamins
 Water
1. Carbohydrates
 . Carbohydrates are made up of carbon, hydrogen and oxygen.
 Used as a source of energy for the body
 liver, muscles and brain stores carbohydrate in the form of glycogen
 Excess carbohydrate converted to fat, which is stored in the body. .
 Glucose is the sugar made by plants in photosynthesis and it is vital in cells for energy.
 Carbohydrate-rich foods include injera, fatira. honey, Potatoes, rice and dabo
 three main types carbohydrates, depending on the complexity of the molecules:
 simple sugars,
 double sugars
 complex sugars
I. The simple sugars (monosaccharide); one sugar unit
 It contains one oxygen and two hydrogen atoms for a single carbon atom
present in the molecule. This can be written as a general formula: (CH2O)n
 The common examples of simple sugar are glucose, fructose galactose;
 All have the same chemical formula C6H12O6.but different in structure
 Fructose, the sugar found in fruit and honey
II. The double sugars (Disaccharide); two sugar unit
 Double sugars are made up of two simple sugars joined together by
condensation reaction.

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  Condensation reaction joins two simple sugars to form a double sugar, and a
molecule of water (H2O) is removed.
 The bond formed between two simple sugar are glycosidic bond
 some of the more common ones double sugars :
Disaccharide Source
 Sucrose (cane sugar) ;  Stored in plants such as sugar beet
glucose + fructose and sugarcane
 Lactose (milksugar);  carbohydrate found in milk
glucose + glucose
 Maltose( malt sugar);  found in germinating seed such as
glucose+ glucose barley
 G





 Glucose is a common simple sugar found in all double sugar
 Sweet taste and ability to dissolve in water is common to simple and double
sugars
Condensation

+ Hydrolysis

Glucose + glucose Maltase

III. Complex sugar (polysaccharide)

 Made up of many single sugar units are joined to form a long chain.
 Do not dissolve in water and have no sweet taste
 Form very compact molecules for storing energy.
 physically and chemically very inactive, storing them does not interfere with
the other functions of the cell
 Some common example of complex sugar are starch, glycogen and
cellulose
 Starch
 Important in energy store in plants.
 The sugars produced by photosynthesis converted to starch.
 plant storage organs such as potatoes are rich in starch
 Glycogen
 Sometimes referred to as ‘animal starch’.
 Storage form of carbohydrate in animal
 Found mainly in muscle liver and brain tissue because;
 They are very active and needs a readily available energy supply at all times.
 Cellulose
 Important structural material in plants.
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  It is the main constituent in plant cell walls.
 Just like starch and glycogen it consists of long chains of glucose.
 Human beings cannot digest cellulose because cannot break down the linkages
between glucose molecule.

2. Proteins
 Proteins are made up of the elements carbon, hydrogen, oxygen and nitrogen.
 Important in growth and repair of tissue
 Protein-rich food includes;
 meat, fish,
 dairy products such as cheese and milk
 Pulses, such as white pea beans, chick peas and red kidney beans.
 Proteins are used for body-building;
 About 17–18% of body is made up of protein – a high percentage next to water
 The highest abundance of organic compound in the body.
 Proteins are polymers, made up of many small units called amino acids.
 20 different naturally occurring amino acids and joined together form proteins
 Amino acids are joined together in a condensation reaction and a molecule of
water is lost.
 The bond formed between two amino acids is known as a peptide link.
 Amino acids dissolve in water. However;
 Some proteins are insoluble in water. These proteins are found in;
 Connective tissue, tendons , matrix of bones (collagen),
 The structure of muscles,
 The silk of spiders’ webs and silkworm cocoons
 Keratin that makes up hair nails horns and feathers.
 Proteins soluble in water.
 antibodies,
 enzymes
 hormones,
 A rise in temperature or a change in pH destroy the 3-D structure of cellular
proteins
 Lack of protein in the diet may result in diseases known as protein-energy
malnutrition.
 The best known of protein-energy malnutrition are marasmus and kwashiorkor.

1) Marasmus, deficiency in calories

 Protein energy malnutrition predominantly due to prolonged calorie
deficit.
 Inadequate energy intake including protein
2) Kwashiorkor; deficiency in protein.
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  A malnutrition disease caused by sever protein deficiency usually
occur when the child is weaned ( stop breast feeding),
 A protein deficiency with adequate energy intake

3. Lipids -Fats and oils

 Lipids are made up of carbon, hydrogen and oxygen. However, a considerably lower
proportion of oxygen in lipid molecules.
 Lipid-rich foods include, butter, beef fat, oil, Plant seeds like groundnuts and coconuts are
also rich in lipid.
 Importance of lipids ;
 Storage of energy in the body
 Structural component of cell membrane
 Insulation layer under skin
 Regulation of body temperature
 Lipids contain more energy per gram than carbohydrates or proteins.
 All lipids are insoluble in water, but dissolve in organic solvents. What is the use of this?
 Fats and oils are made up of combinations of two types of organic chemicals, fatty acids
and glycerol.( C3H8O3)
 There are two main ways in which fatty acids vary;
 the length of the carbon chain can differ
 The fatty acid may be saturated or unsaturated.
 saturated fatty acid
 Carbon atom is joined by a single covalent bond.
 More common in animals lipids
 Solid at room temperature
 saturated fat, in diet are not good for our long- term health
 unsaturated fatty acid
 The carbon chains have one or more double bonds in them.
 more common in plant lipids
 liquid at room temperature
 Relatively healthier contain less number of cholesterol
 When a molecule of glycerol combines in a condensation reaction with three fatty acids, a
lipid is formed
 Lipids include the highest profile chemicals in public health issues – cholesterol and fat.
 Cholesterol need to make;
 The membranes of your body cells
 Sex hormones
 The hormones which help your body deal with stress.
 But high levels of cholesterol in blood increase risk of getting heart disease or diseased
blood vessels.
4. Minerals;
 Group of nutrient found in a small amount and classified as micronutrients
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  Important for the proper function of the body
 Lack of mineral in the diet may result in a deficiency disease

Mineral role in body foods rich in mineral Deficiency disease

Calcium Making bones and teeth Dairy products, fish, bread, Rickets
Blood clotting vegetables
Phosphorus Making teeth and bones; part Most foods Improper formation of
of many chemicals, e.g. teeth and bones; failure
DNA,ATP of metabolism
Sodium For proper fluids balance, Common salt, most foods Dehydration, shock
nerve transmission and Muscular cramps
muscular contraction
Chlorine For proper fluids balance, Common salt, most foods Muscular cramps
stomach acid
Magnesium Making bones, nerve Green vegetables Skeletal problems, cell
transmission, muscular chemistry affected,
contraction and immune defects in metabolism
system health
Iodine Synthesis of thyroxin Table salt, onion Goiter
Iron hemoglobin synthesis; helps Red meat, liver, eggs, green
carry oxygen and result in leafy vegetables, e.g. spinach Anemia
energy production

5. Vitamins
 Vitamins are important in regulation and maintenance of health body
 Lack of vitamin in the diet cause deficiency disease
 Vitamins are classified into two groups
 Fat soluble vitamins; vitamin A,D,E,K
 Water soluble vitamin C and B group

Vitamins Role in the body Food rich in the Deficiency disease

body
Vitamin A To make cell of Carrots, vegetable. Night blindness
Retinol retina Fish Dry skin
Vitamin B1 Used in cellular Meat and cereal Beri-beri
Thymine respiration
Vitamin C Helps to heal wound Lemons, orange, Scurvy (bleeding of
Ascorbic acid for healthy gum vegetable gum)
Vitamin D Helps calcium and
Calciferol phosphate to be used
for making of bone
Vitamin E Affect muscle and Vegetable, Cereals, Infertility in rat
Tocopherol reproductive system meat

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 in animals
Vitamin K For the formation of Liver, cheese, milk, Failure of blood to
phyloquinone blood clotting vegetables clot

6. Water
 The most abundance substance in the body. It constitutes between 60 and 70% of the
body.
 Some of the biological role of water
 A medium of chemical reactions– it is a vital solvent.
 Water is involved in the transport of substances around the body food,
hormones, waste products such as urea
 Water is involved in temperature regulation as lose heat from the body through
sweating
 Water is involved in the removal of waste materials such as urea
 Water is a reactant in many important reactions in the body for example,
hydrolysis reactions.
 Water is needed for the osmotic stability of the body
7. Fiber (Roughage )
 Fiber Important part of a healthy balanced diet
 Roughage or fiber cannot be broken down, digest or absorb in the human gut
 It can help to prevent heart disease, diabetes, weight gain , some cancer and improve
healthy diet
 Fiber also important in lowering cholesterol, blood pressure, glucose level and
inflammation
 It is an essential part of diet because it provides bulk for the intestinal muscles to work
on.
 Low in roughage a diet results in the movements of food through the gut are sluggish
and the food moves through the gut relatively slowly. This can result in constipation
Food test
Food Reagent used Positive result
Carbohydrates
 Starch  Iodine solution  Blue black color
 Reduced sugar. E.g.  Benedicts solution  Orange red precipitates
glucose
Proteins
 Biuret test  Biuret reagent  Purple color
Lipids
 Filter paper test or  Piece of paper  Translucent spot
oil spot test
 Emulsion test  Ethanol solution  Milky suspension
Vitamin C E.g. orange  DCPIP  Colorless
or lemon juice (dichlorophenol indo
 DCPIP solution phenol) reagent

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 Balanced diet taking food from all major food groups in order to maintain a healthy body
 Malnutrition diet is lacking in important elements needed for a healthy body
 Undernutrition too little food is eaten. Overnutrition too much food is eaten

 Body/mass index or BMI. This compares weight to height in a simple formula:

BMI = weight /(height)2
Most people have a BMI in the range 20–30. Have health weight
 But, if a BMI of below 18.5, or above 35, then may have some real health problems.

 Exercises
1. When some juice was added to DCPIP .The solution changed into colorless .This shows that
the solution contains;
A. Glucose B. Vitamin C C. Protein D. Lipids
2. The growth and maintainace of organism depends on?
A. Glucose B. Water C. Protein D. Lipids
3. . Which of the following The major role of carbohydrate in human diet is:
A. form cell membrane C, Catalyze cellular reaction
B. Supply energy to the body D. provide building blocks for protein
4. in equal weight of the following substance are oxidized, the large amount of energy is release
by? A. protein B. fat C. Starch D. Sugars
5. Which of the following organic tissue is most abundant in animal tissue?
A. Protein B. Lipids C. carbohydrates D. minerals

III.2 DIGESTIVE SYSTEM

 Digestive system is the system in which food substances are broken down into small soluble
molecules.
 Digestion is the process in which large, complex and insoluble food particles are broken
down into smaller, simpler and soluble form that can be used by the body.
Two stage of Digestion
 Physical [mechanical] digestion
 Food is mechanical broken down by teeth and muscular activity of the gut.
 Involves cutting, grinding, chewing food in the mouth.
 Important to increase surface area of the food to act upon.
 Chemical digestion
 It involves the breaking down of food by hydrolysis reaction
 Change large insoluble food into smaller and soluble form
 chemical breakdown is controlled by enzymes

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 ENZYMES

 Enzyme are biological catalyst that speed the rate of chemical reaction
 Properties of enzyme include
 Enzyme are protein
 Enzyme are biological catalyst
 Not affected by the reaction they speed up
 Enzyme can be re--used
 Enzymes are very specific. E.g. amylase breaks down starch, lipase breaks down fats,
catalase breaks down hydrogen peroxide but pepsin breaks down proteins
 Enzyme can be divided into two
 Intracellular enzyme are enzyme that work inside side the cell
E.g. Respiratory enzyme
 Extracellular Enzyme are enzyme that work outside the cell
E.g. Digestive enzyme
 Process that occurs in digestive system
 Ingestion the taking of food into the mouth
 Digestion breaking down of food into smaller, simpler and simpler forms
 Absorption taking in and used of digested food into the blood stream.
 Assimilation the use of digested food by the body
 Egestion the removal of undigested food from the body.

1. Digestion in the mouth

 Both physical and chemical digestion starts in the mouth
 Physical digestion carried out by grinding and chewing action of teeth and rolling of tongue
 Chemical digestion carried out by action of enzymes called salivary amylase /ptyline/
 salivary amylase /ptyline/ digest starch to maltase
 Mastication or chewing is the process by which food is crushed and grind by teeth
 The first step of digestion which increase surface area of the food for enzyme action
TEETH
 Teeth are needed for a variety of different jobs – gripping food, tearing food and chewing
food,
 Type of teeth
 Incisors used for biting
 Canines
 Premolar used for chewing and crushing food
 molar
 Cross section of the teeth
 Enamel the top surface the teeth, the hardest structure of the body
 Dentine living layer underneath tooth enamel, dentine contains many fine channels
filled with cytoplasm, which supplied with oxygen and nutrients by the blood vessels in
the pulp cavity
 pulp cavity centre of the tooth which contains nerves and blood vessels
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  Cement fibrous layer that holds teeth in jaw bone

 The longitudinal section of teeth

 Crown; the upper part of tooth
 Root; embedded in jaw bone
 Neck; narrow region between root and crown
 Periodontal disease bacterial infection of the gum
 Dental plaque a mass bacteria combined with food and saliva, form a thin biofilm
which the bacteria grow with in the mouth
 Symptoms include tender gums (bleeding gums ) when you clean your teeth
 Ways to avoid tooth decay include:
 Regular brushing of teeth and gums twice a day. This removes the plaque from the
teeth, preventing the build-up of a sticky, acidic film over the enamel.
 Avoiding sweet, sugary foods
 Have regular dental check-ups.

 Moving the food along the esophagus

 The saliva coated chunk of chewed food is called bolus
 Swallowing is a reflex action.
 During Swallowing epiglottis closes over the trachea, preventing food going down into
lungs. swallowing and breathing cannot occur at the same time
 Muscular contractions of the gut moves swallowed food down esophagus /gullet/
 Peristalsis is a wave like muscular contraction that moves the food along the gut.
 Waves of alternate contraction and relaxation of the circular and longitudinal muscles move
food from one end of the gut to the other

2. Digestion in the stomach

 The stomach wall contain gastric gland which secrete gastric juice
 Gastric juice contain
 Hydrochloric acid /HCL/
 Provide correct PH for pepsin
 Kill micro-organism which are swallowed with food
 Pepsin a protease enzyme that convert protein into peptones
 Renin used to solidify milk protein

 Function of stomach
 Digestion of protein
 Formation of chime
 Temporary storage 0f food

3. Digestion in Small intestine

 It is a place where most digested food take place
 Has three parts
 Duodenum
 Jejunum
 Ileum
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 I. Duodenum
 The upper part of small intestine
 Do not secret its own enzyme
 Digestion facilitated by the secretion of liver and pancreases.
 The liver
 Liver secret bile stored in gall bladder
 Bile used
 Neutralize the acidity chime
 Emulsifies fat into tiny droplets
 Pancreases
 Secrete pancreatic juice which is passed in to duodenum through pancreatic duct
 Contains three enzyme
 Lipase; hydrolysis fat into fatty acid and glycerol
 Trypsine; Protease enzyme break down peptones into peptide
 Pancreatic amylase; Carbohydrase enzyme break down starch into maltase
II. Jejunum; the middle part of small intestine
III, Ileum
 The lower part of small intestine
 All digestive process are completed and soluble food are absorbed into the blood strem
 Intestinal wall secret intestinal juice , which contain;
 Erepsine; convert peptides into amino acid
 Lipase; converts fat into fatty acid and glycerol
 Maltase; converts maltose into glucose
 Lactase; converts lactose into glucose and galactose
 Sucrose; converts sucrose into glucose and fructose
Absorption and assimilation
 Absorption is the process by which the end product of digestion pass from the wall of small
intestine and enter into blood stream
 Some of the factors that make the absorption of the digested food very efficient in small
intestine is;
 It has many finger-like projections called villi, to increase the surface area for
diffusion, and each individual villus have smaller projections called microvilli.
 Have a rich blood supply that carries away the digested food molecules.
 Short diffusion distances.
 The glucose molecules and amino acids go directly into the blood.
 The fatty acids and glycerol move initially into the lacteals, which are part of the lymph
system.
 hepatic portal vein blood vessel that takes digested food molecules to the liver
 Assimilation taking in and use of digested food by the body

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 Issues of digestive health
 Constipation
 If the faeces remain in your large intestine for too long, too much water is removed from
them.
 Become compacted, hard and difficult to remove from body.
 The most common causes;
 Lack of fibre in the diet
 Not drinking enough water.
 Pass faeces can cause haemorrhoids (piles) or a tear in the anus.
 Constipation can be treated relatively easily.
 Eating more fibre drinking plenty (so the faeces remain soft)
 Taking laxatives (chemicals which stimulate the gut to contract and force out the
faecal material)..
 Diarrhoea
 Diarrhea the faeces that are produced very loose and watery.
 Diarrhea can be fatal as it causes dehydration of the tissues.
 Can be treated very simply by giving the sufferer frequent drinks of water with
rehydration salts.
 These replace the fluids that are being lost and keep the body tissues hydrated until the
immune system overcomes the infection.
 Exercise
1. Which of the following digestive processes is affected if the gall bladder is surgically
removed?
A. Digestion of lipid C. Digestion of protein
B. Digestion of protein D. Digestion of vitamins
2. The two human teeth types that are used for biting are;
A. Canines and premolars C. premolars and molar
B. Molar and incisors D. Canines and incisor
C.

3.3. RESPIRATORY SYSTEMS

 The human respiratory system are a serious organ responsible for taking in oxygen and
expelling carbon dioxide
 The human respiratory system consists the following structures
1) The nasal passages
 Have a large surface area,
 A good blood supply, used warms the air
 Lots of hairs. used to trap dust particles some bacteria
 Lining secretes mucus., used to moist the air
 So breathing through nose is good because the air we breathe in is warm, clean and
moist before it gets into the delicate tissue of the lungs.

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 2) Pharynx; found behind the nasal cavity and mouth
 is a common passage of air and food
3) Larynx; voice box, where sound is produced
4) Epiglottis; Prevents the entrance of the food into the trachea during swallowing of food
5) Trachea; wind pipe
 Contain C shaped ring of cartilage keep open all the times
 The opening of trachea is called glottis
 Divided into two bronchi
6) Bronchi (singular bronchus) leading to each lung , Connects trachea to bronchioles
7) Bronchioles; are small tube branching from each brunching the lung
8) Alveoli; air sac
 Is the site of gas exchange between blood capillaries and the lung
 alveoli provide an ideal site for the most effective possible diffusion of gases into and
out of the blood
 oxygen moves into the blood where as carbon dioxide moves out of the blood
 The mechanism of gas exchange in the alveoli depends on;
 large surface area
 moist surfaces
 short diffusion distances
 rich blood supply

 The lung
 The major breathing organ of animals
 Surround by a membrane called plural membrane
 Protected by ribs, sternum, vertebral column, diaphragm and intercostals muscles

 The mechanism of breathing

 The movement of air in and out of the body is known as ventilation of the lungs
 Breathing involves two process inhalation and exhalation
 Comparisons of Inhalation and Exhalation
Inhalation /inspiration/ Exhalation/expiration/
 Air enters into lungs  air pushed out of lungs
 Diaphragm muscles contract become  diaphragm muscles relax , becomes
flatten dome-shape
 External intercostals muscles contract,  Internal intercostals muscles contract,
 Ribcage moves upward and down ward  Ribcage moves down and inward
 Composition
 Volumeof ofinhaled and exhaled air
thorax increase  Volume of thorax decrease
 Pressure of thorax decrease Inhaled air  PressureExhaled air decrease
of thorax
Nitrogen About80% About About 80% About
Oxygen 21% 16%
Carbon dioxide 0.04% 4%
Water vapor Less High
Heat Less High

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 Demonstrating the presence of carbon dioxide (CO2) in exhaled air
 To demonstrate the presence of carbon dioxide (CO2) in exhaled air. Use;
 Lime water (Ca(OH)2) as an indicator of the presence of carbon dioxide.
 The clear liquid turns cloudy when carbon dioxide is bubbled through it,
 Demonstrating the presence of water vapor in exhaled air
 To demonstrate the presence of carbon dioxide (CO2) in exhaled air. Use;
 Blue cobalt chloride paper turns pink in the presence of water,
 White anhydrous copper (II) sulphate turns blue.
 Breath out on a glass surface or mirror results in a droplet of water or moisture
 Demonstrating the presence of heat in the air breathe out
 Temperature of the air breathe out is higher than the temperature of breathe in
 Breathing on the back of the hand result in warm fealing

What affects breathing rate?

 The average resting breathing rate for an adult human being is around 12–14 breaths per
minute.
 Tidal volume of air breathing normally at rest, you take about 500 cm3 of air in and out each
time you breathe – this is only about 15% of your possible maximum. This is known as your
 The vital capacity of are the absolute maximum amount of air take into or breathe out of
lungs.
 What factors affect breathing rate?
 The main factors affect breathing rate are
1. Exercise 2.Anxiety 3. Drugs 4. Environmental factors 5.Altitude 6.Weight
7.Smoking

 Group assignment discuss in one two five educational group on the main factor which
affect breathing rate

3.4. CELLULAR RESPIRATION

 Cellular respiration is a process in which energy is released from the breaking down of
organic substance in the body
 Cellular respiration is a serious biochemical reaction release energy from food
 All cells need energy to carry out the reaction of life, and respiration provide this energy
 Respiration release energy from the food we eat so that the cell of the body can use it
 The energy that is used by the cells is stored in the form of molecule called ATP
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  ATP; stands for adenosine tri phosphate
 Adenosine molecule attached to three phosphate
 ATP is immediate source of energy for the cell
 ATP energy currency of a cell
 The direct energy source for each cell
 During respiration ATP is made from ADP (adenosine diphosphate) and
phosphate (Pi) ADP + P energy produced ATP + H2O
 When energy is needed for any chemical reaction in the cell, the third phosphate is
energy required
broken by a hydrolysis reaction ATP + H2O ADP +P

 Importance of ATP to the body

 To carry out basic function of life known as metabolism ( anabolism+ catabolism)
 Anabolism; build up large molecule from smaller one to make new cell material
 Catabolism; break large molecule into smaller one
 For muscle contraction
 To regulate core body temperature in homeotherms
 Provide energy for active transport material across cell boundaries.
Type of respiration
 Based on the requirement of oxygen, respiration can be classified;
I. Aerobic respiration
 Production of energy using oxygen
 Relatively high amount of energy is produced than anaerobic respiration
 Takes place in the mitochondria of a cell
 An organelle found in almost any cells
 Have a folded inner membrane to provides a large surface area for the enzyme
involved in aerobic respiration
 Muscle cell, liver cell and cones and rods of eye have a lot of mitochondria because
they use a lot energy
 Carbon dioxide and water are produce as waste product
 Glucose + oxygen carbon dioxide + water + ATP
C6H12O6 + O2 CO2 + H2O +38ATP
II. Anaerobic respiration
 Do not utilize oxygen
 Less amount of energy is produced. Only 2ATP from one glucose is produced
 It mostly produced in the cytoplasm of a cell

1. Anaerobic respiration in animal cell ( Lactate fermentation)

 During heavy exercise the muscle cell respire anaerobic ally
 Produce a waste product called lactic acid
 The body cannot get rid of lactic acid
 The accumulation of lactic acid during exercise cause muscular ache
 The amount of oxygen needed to breakdown lactic acid oxygen dept
 Anaerobic respiration in muscle cell
 Glucose Lactic acid +2ATP

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  After exercise, the lactic acid is completely oxidize(broke down) by oxygen into carbon
dioxide and water in the liver
Oxygen dept repayment
 Lactic acid + oxygen carbon dioxide + Water

2. Anaerobic respiration in yeast cell (Alcoholic fermentation)

 When yeast have plenty of oxygen
 Respire aerobically and produce carbon dioxide and water
 Carbon dioxide produce in aerobic respiration of yeast cell makes the dough to
rise which also gives it tangy flavor so that used for making bread and injera
 Yeast can also respire anaerobically
 Yeast cell break down sugar into ethanol and carbon dioxide
 Glucose Ethanol + carbon dioxide +2ATP
 Anaerobic respiration in yeast result in making alcoholic drinks

 Exercise
1. Which of the following is not the product of aerobic respiration?
A, oxygen B. Water C. carbon dioxide D. ATP
2. The reaction lactic acid + oxygen ®carbon dioxide +water
A. Aerobic respiration B. Oxygen dept repayment C. lactate fermentation
3. Which of the following is the product of both aerobic and anaerobic respiration of yeast?
A. Ethanol B. Carbon dioxide C. Lactic acid D. Water
4. Lactic acid completely oxidize into carbon dioxide and water in the
A. Muscle cell B. Liver cell C. Pancreases D. Kidney
5. The fermentation of glucose by yeast produces
A. CO2,H2O and 2ATP . C. lactic acid ,2ATP
B. Ethanol, CO2 and 2ATP D. CO2, H2O and 36ATP
6. Cellular respiration is a series of biochemical reaction that:-
A. Make sugar from sun light C. Release energy from sunlight
B. Make energy from sunlight D. Release energy from food
7. Yeast is used in baking bread because. They produce:-
A. Ethanol B. Oxygen C. CO2 D. Lactate
8. What molecule is essential for aerobic respiration to take place?
A. N2 B. O2 C. CO2 D. Ethanol

3.5. CIRICULATORY SYSTEM

 Circulatory system is a system in which ox


 ygen, digested food and other nutrients transport to all part of body.
 All organism do not have specialized circulatory system. Small, single celled organism
relies on simple diffusion to exchange material between the environment and their cells.

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  CIRCULATION is the movement of blood and other fluid through blood vessels to all parts
of the body.
 The human transport system is the blood circulatory system
 It has three elements
1. Heart ( pump)
2. Blood vessels ( pipe)
3. Blood ( medium)
1. HUMAN HEART
 Made up of cardiac tissue
 It is a muscular blood pumping organ
 Surrounded by a double membrane called pericardium
 Human heart has four chamber
 Two atria ( auricles) upper chamber
 Two ventricles lower chamber
 The right auricle receive deoxygenated blood from all part of the body through vena cava
 The left auricle receive oxygenated blood from lung through pulmonary vein
 The right ventricle pump deoxygenated blood to lung whereas left ventricle pump
oxygenated blood to all part of the body
 Left ventricle is the thickest chamber of the heart because it pumps blood longer distance
 The left side of the heart separate from the right side by septum
 The muscle of the heart supplied oxygenated blood by coronary artery

 Valves the structure of the heart prevent the back flow of blood
Tricuspid valve
 the valve between right atrium and right ventricle
 prevent the back flow of blood from right ventricle to right atrium
Bicuspid (mitral) valves
 The valve between left atrium and left ventricle
 Prevent the back flow of blood from left ventricle and left auricle
Simi-lunar valve
 Found at the opening of pulmonary artery and aorta
 Prevent the back flow of blood into ventricle

 The contraction of the heart chamber is stimulated specialized tissue called pacemaker
 An instrument used to listen the heart beat is stethoscope
 An average heart rate of human being is 72 times per minute.

 Systole
 The contraction of the heart chamber
 Force the blood out of the heart
 Diastole
 The relaxation of the heart chamber
 Fills the chamber of the heart with blood
 Systolic blood pressure

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  Pressure formed by the contraction heart chamber
 Forced blood out into arteries
 Blood pressure at highest reading
 Diastolic blood pressure
 Pressure exerted by the relaxation of the heart chamber
 Blood pressure at lowest reading
 The normal blood pressure of human being is 120mmHg/80 mmHg
 The nominator is systolic and denominator is diastolic Pressure

2. BLOOD VESSELS
 Blood vessel are the pathways through which transportation of material takes place
There are three main type of blood vessels

 Arteries
ARTERIES SUPPLY OXYGEN
 Veins
TO;
 Capillaries
Carotid artery Head
 ARTRIES
Coronary artery Heart muscle
 Carry blood away from the heart
Renal artery Kidney
 Thick and elastic wall
Hepatic artery liver
 Thick muscle layer
 Have elastic fiber
 Small /narrow/ lumen
 Blood flow rapid
 High pressure and pulsate
 No valves
 Mostly deep seated
 Blood oxygenated except
 Pulmonary artery carry deoxygenated blood to lung
 Umbilical artery carry deoxygenated from fetus to placenta
 Largest artery aorta smallest arterioles

 VAINS
 Carry blood back to the heart
 Thin wall
 Thin muscle layer
 No elastic fiber
 Big /wider/ lumen
 Blood flow slowly
 Low pressure and pulsate

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  Have valves
 Mostly superficial
 Carry deoxygenated blood vessels
 Pulmonary vein return oxygenated back from lung to heart
 Umbilical vein carries oxygenated blood placenta to fetus
 Largest vein vena cava smallest venules
 CAPILLARIES
 Narrow thin walled blood vessels
 Connects arteries and with veins
 Take blood to the tissue and cell
 Site of exchange of substance within the body
 Wall one cell thick
 Blood flow slowly
 Mix oxygenated and deoxygenated blood
 No valve
3. THE BIOOD
 BLOOD is a fluid tissue that carries nutrient, respiratory gases, metabolic wastes and other
substance
 Blood contains
1) Plasma
2) Blood cells
 Red blood cells
 White blood cells
 platelets
 PLASMA
 A pale yellow liquid portion of the blood
 90% of the plasma is water
 10% consists dissolved and suspended substance
 Caries nutrients , carbon dioxide, hormones, enzymes and nitrogenous waste
 Contain plasma protein such as fibrinogen, prothrombin and Thrombin

 RED BLOOD CELLS (ERYTHROCYTES)

 Biconcave disk shaped non nucleated cell
 Live 100-120 days in your body
 Worn out red blood cell destroyed and removed by liver and spleen
 Thin surface membrane for ease of diffusion
 Used to transport oxygen and carbon dioxide back into the lung
 Formed in the bone marrow
 Contain a red pigment called hemoglobin
 Hemoglobin contain iron, the lack of iron in diet cause anemia

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  Hemoglobin is a complex protein which carries oxygen
High oxygen concentration
Hemoglobin +oxygen oxy-hemoglobin
Low oxygen concentration

 Adaptation of RBC to carry oxygen

 contain hemoglobin
 Does not have nucleus to carry more room for hemoglobin.
 Have biconcave disk shape increase surface area for diffusion of oxygen
 Thin surface membrane for ease of diffusion

 WHITE BLOOD CELL (LEUCOCYTES)

 Collarless, irregular shaped and nucleated
 Produced in bone marrow, lymph nodes and spleen
 Fewer white blood cell then red blood cell
 Much bigger then red blood cell
 Used to defense the body against disease
 White blood cell can be classified
 Phagocytes a group of white blood cell that engulf and ingest infection microbes
 Lymphocytes group which help to produce antibodies

 PLATLATES (THROMBOCYTES)
 Collarless and non-nucleated
 Important in blood to clot at the site of a wound
 Prevents the body from bleeding to death from a simple cut
 Also protect the body from the entry of pathogen through open wound
 Protect the new skin as it grows

Human blood group

ABO blood group system

 Four major blood group in humans’ Blood group A Blood group AB
Blood group B Blood group O
 Antigens are special protein which are found on the red blood cell
 Antigen allow cells to recognize each other
 Blood group determine by the type of antigen on the red blood cell
 “A” blood contain “A” antigen “B” blood contain “B “ Antigen
 “AB” blood contain “A’ and “B” antigen “O” blood do not contain antigen
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 Antibody are protein which are produces the body to fight foreign antigen and found in the
plasma of the blood
 Two type of antibodies against antigen. These are anti-A and anti B antibodies
 Agglutination is incompatibility of antigen and antibody in blood group
 Blood groups that mix without agglutination are called compatibility
Transfusion of blood group

Blood antigen Antibody Can be transferred Can received

group (donate) into blood from
A A Anti-B A and AB A and O
B B Anti-A B and AB B and O
AB A and B NONE AB only A, B,AB,O
O NONE Anti A and B A,B,AB,O O only
AB universal recipient O Universal donor

 There is another antigen found on the surface of RBC called Rh antigen

 A person who do have this antigen is called Rh+ (Rh positive)
 A person who do not have this antigenic called Rh- ( Rh negative)
 Rh system in relation to marriage

Mother Father
 Rh+ Rh+ no problem
 Rh- Rh- no problem
 Rh- Rh+ may be a risk Why?
 Rh+ Rh- no problem
A DOUBLE CIRCULATION
Double circulation is the two transport system of the body these are;
1. pulmonary circulation
 The pathway of blood between heart to lung
 Important to exchange oxygen and carbon dioxide
 Right ventricle pulmonary artery lung pulmonary vein left auricle

2. systematic circulation
 the pathway of blood form heart to all part of the body
 supply oxygen rich blood to all part of the body
 systematic circulation can be divided into:
 Hepatic circulation the pathway of blood between heart to liver
 Renal circulation the pathway of blood between heart to kidney
 Coronary circulation the pathway of blood between heart to heart muscle
 Hepatic portal circulation carries digestive nutrient from the digestive system to the
heart through the liver.

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 COMMON PROBLEM OF CIRCULATORY SYSTEM

 ANEMIA
 Is caused few red blood cell or if the level of hemoglobin is less by
 Most commonly caused by the lack of iron in the diets
 Treated by eating iron rich diets such as liver, meat, egg, green leaf vegetable
 Girls are more likely to be anemic then boys because they lost iron in their menstrual
bleeding
 HYPERTENSION
 High blood pressure above140/90 mmHg
 Caused by various reason such as
 Age. Over weightiness
 High consumption of salt
 Drug addiction
 Diabetics etc.
 Can be reduce and controlled by;
 Eating less fat and salt
 Regular exercise
 Avoid use of drug etc

UNIT 4
MICRO-ORGANISM AND DISEASE

1.4. MICRO-ORGANISM

 Are organisms too small to be seen with the naked eye

 Micro- organisms can be seen with the aid of microscope
 Micro-organism have useful and harmful aspects
 Useful aspect of micro-organism

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  Decay and recycling of nutrients
 Used in the making of food, Such as injera, ergo and eyib
 Produce alcoholic drinks such as beer, wine and tej
 Important in genetic engineering
 Harmful aspect of micro-organism
 Cause disease in plant ,animals and humans
 Food poisoning bacteria cause spoilage of food
 Micro-organism includes bacteria’s, viruses. Molds. Yeast
BACTERIA
 Bacteria are a single called organisms
 Smaller than the smallest animal and plant cells
 Are unicellular and prokaryotic organisms
 Bacterial cell have many similarities to animal and plant cell. They are made up of
cell wall, cell membrane, cytoplasm and genetic material
 Some bacteria have flagella(for movement)and capsule(for protection)
 Bacteria are classified based on shape into rod shaped(bacilli), round(cocci),
comma(vibro) and spiral
 Bacteria can also be classified into gram positive and gram negative based on gram stain
 Gram stain is a differential stain used to classify bacteria into two
 Different bacteria have different cell walls which take up the stain differently
 Stages of gram stain
1) Cristal violet/purple color/; primary stain
2) Iodine solution; as a mordant /to form iodine-- violet complex/
3) Decolorized by ethanol
4) Safranin /red color/; counter stain or secondary stain
 Gram positive
 Keep the color of primary stain /crystal violet/ not decolorized
 Stain purple
 Gram negative
 Primary stain decolorized by ethanol
 Take the color of secondary stain safranin
 Stain red/ pink/

Viruses
 Smaller then bacteria
 Neither prokaryotic nor eukaryotic cell.
 Viruses are a particle, made up of a protein coat( capsoid) and genetic material
 The genetic material is either DNA or RNA
 They are obligate parasite
 Viruses are considered to be living and non-living things. How?
 Do not carry out any of the function of normal living organism except reproduction
 Viruses only reproduce inside living cell
 Viruses cause some common human disease such as AIDS, Influenza, rabbis

Fungi
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 1. Yeast;
 Is a single called fungi
 At anaerobic condition yeast carry out alcoholic fermentation
 Yeast have heterotrophic mode of nutrition
 Yeast reproduce asexually by budding
2. Moulds
 Made up of filament called hyphae
 A mass of hyphae together forms mycelium
 Reproduce asexually by spore formation

 Germ theory diseases states that germ are the cause of disease
 The theory of spontaneous generation states that living things arise from non living
things
 Louis Pasteur disproves the theory of spontaneous generation. How?
 Louis Pasteur indicates that, infectious disease caused by pathogenic micro-organism.
He also introduces pasteurization technique.
 Robert Koch discovered the first disease causing micro-organism called bacillus
anthracites which cause anthrax

Controlling micro-organism
The major methods of controlling microorganisms include;
 Sterilization
 Disinfectants
 Pasteurization

1) Sterilization;
 is the process of complete removal of micro-organism
 some of the methods that are used as sterilization;

A. autoclave sterilization
 Used to sterilize;
 Equipments which are not damage by heat
 Bacterial spores which do not die at low temperature
 Killing micro-organisms by boiling them in water at 1200C under high pressure
for 15-45 minutes.
B. Ultra high temperature (UHT)
 It is a way of treating food to kill all the micro-organism found in it.

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  It is a techniques of heating the food at a temperature of 1350c to1500cfor 2-6
second
 Used in food processing industries to prevent contamination of food

C. Dry heat sterilization

 Used to sterilize scientific equipments
 Requires higher temperature high temperature and longer period of time
 Use the temperature of 1700C for one hour and1600C for two hour
2) Pasteurization
 Involves boiling or heating of milk, bear, other food staff
 It include heating followed by rapid cooling
 The temperature used
 62.90C for 30 seconds
 71.60C for at least 15 seconds
3) Disinfectants
 Chemicals that are used to kill micro-organisms on inanimate object
 Disinfectants have the following characteristics
 Fast acting
 Effective against all type of micro-organism
 Disinfect material without damaging or discoloring it
 Dilute bleach and calcium hypochlorite used as disinfectant on drinking water
 Antiseptics
 Chemicals (Disinfectants) that can be applied to a living tissue such as skin
 Help to protect the entrance of germs if the skin is cut or damage
Culturing (Growing) Microbes
 Importance of growing micro-organism
 To know how to kill them
 To develop vaccine
 To identify useful and harmful aspect

 Precondition for growing micro-organism;

 Isolating the type of micro-organism to be studied
 Developing suitable nutrients medium
 Suitable environmental condition
 Nutrient medium; nutrients required for the growth of micro-organisms
 It can be solid or liquid
 Agar
 As solid nutrient medium which is extracted from red algae
 Micro-organism are cultured in a petridish
 Broth
 A liquid nutrient medium
 Micro-organism are cultured in test tube
 Culture media; is a collection of nutrients and microbial cells grow on medium

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  Inoculation; a technique of transferring microbes into a nutrient medium
 Inoculating loop / needle/; an instrument that is used to transfer micro-organism
 Culture microbes should transfer in a zigzag streaks because to avoid
competition
Immune system
 Immune system the system in the body which protects against disease causing micro-
organisms and foreign proteins ( antigen)
 Immunity the ability of the body to resist disease
Type of immunity
i. Innate immunity
 Natural ability of the body to fight disease producing micro-organism
 Immunity present at the time of birth against certain diseases
 Nonspecific antibodies against disease germs
 Inborn and is due to the presence of naturally occurring antibodies since birth
 It obtain without the stimulation any foreign bodies
ii. Acquired immunity
 Immunity developing during the life time of individual after birth
 Acquired immunity either active or passive
Active immunity
1. Natural active immunity
 Immunity resulting from having had a disease previously
 The infection stimulates the body to form its own specific antibodies
against germs
2. Artificial active immunity
 Immunity acquire artificially by receiving vaccine
 Vaccination /Immunization/the use of dead or weakened pathogens to produce
immunity to dangerous disease
 Vaccine stimulated the body to form its own antibodies without having a
disease
 A child receive vaccines for polio, tetanus, tuberculosis, hepatitis, measles,
mumps, diphetria

Passive immunity Review question P.136-137

1) Natural passive immunity
 Immunity passed from mother to child
 Antibodies from the mother pass into fetus across placenta
 Many antibodies are passed to the baby through breast milk
2) Artificial passive immunity
 Introducing artificially antibodies into the body give immediate immunity
 Antibodies are drugs/ chemicals/which kill bacteria inside our body but do not harm
human cell.
 Antibiotics have no effect on disease caused by viruses
 Penicillin is the first antibiotic produce by Alexandor Flemming

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 2.4. DISEASES

 Disease is a disorder state of an organ or organism

 Some of the most common human disease in Ethiopia
1) Tape worm
 Tape worm live in the intestine of host
 Have head or scolex which help to attach to the wall of intestine
 Scolex have suckers and hooks used to attach the intestinal wall
 They have segmented body called proglottids
 The two most common tape worms that infect human are; beef tape worm (Taenia
saginata )and pork tape worm (Taenia solume )
 Beef tape worm cattle intermediate host and pork tape worm pig intermediate host
 Transmissions

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  Eating raw or undercooked meat
 Symptoms
 Vitamin B12 deficiency
 Weight loss
 Control and prevention
 Use proper latrine
 Meat inspection
 Meat should be cooked well fig. tape worm
 Special adaptation of tape worm to service inhuman gut
 Scolex has hooks and suckers helps the parasite attached to small intestine
 Flattened body absorbed digested nutrient over a large surface area
 Thick cuticle to prevent from intestinal enzymes
2) Tuberculosis(TB)
 Cause
 The bacteria called mycobacterium tuberculosis
 Symptoms TB usually affect lung (pulmonary TB)
 Loss of weight but it can also affect kidneys, lymph
 Persistent cough nodes, joints and bones
 Night sweat
 Loss of appetite
 Fever and chest pain
 Blood in sputum
 Transmission
 Through air droplet cough , sneeze
 Infected milk
 Prevention
 Pasteurize milk
 Vaccination
 Avoid droplet infection
 Antibiotics


1) Malaria
 Vector born disease ( vector an organism that transmit disease causing
microorganisms from one host to another )
 Affect the liver and red blood cells. How?
 Cause; parasite called plasmodium
 Symptoms
 High fever, chills and sweats
 Transmission
 by the bite of female anopheles mosquito
 Preventions
 Avoid contact with mosquito using mosquito repellents, fixing screen on
windows, using net over beds
 Remove mosquito breeding place

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  Biological control ( introducing an organism such as fish into the water that
feeds on larva)
 Chemical control sprayed on to the water in order to kill mosquito larva and
egg
2) Gastroenteritis/acute watery diarrhea AWD/
 If someone suffering from AWD , the lining of the stomach, small intestine, become
inflamed and painful
 Water cannot be reabsorbed by the inflamed lining the large intestine, resulting in
liquid diarrhea
 Caused
 Viruses rotaviruses
 Bacteria salmonella and Escherichia coli
 Protozoa giardia and amoeba
 Transmission
 Eating contaminated food and watery
 Symptoms
 Violet abdominal cramps and pain
 Feeling nauseous, vomiting often both
 Watery diarrhea which does not usually have blood in it
 Slight fever
 General muscle ache and head ache
 Control and prevention
 Wash hands after using toilet, and before preparing and eating food
 Make sure that the water you drink and use to wash salad food and fruit is clean and
safe
 Avoid raw and undercooked meat, egg, fish etc
 Avoid contact with someone has AWD

3) Cholera
 Caused
 Bacterial infection called vibrio cholera
 Transmission
 Contaminated food and water with faces
 Symptoms
 Mild to severe diarrhea
 Vomiting and dehydration
 A pale an water y diarrhea
 Loss of salt and dehydration
 Sever muscular cramp
 Control and prevention
 Replace the fluids and salt to prevent dehydration
 Antibiotics are used to treat disease

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  Everyone has supply of clean, uncontaminated water
 The sewage is disposed effectively
 Avoid consuming uncooked food and water
4) Typhoid
 Cause
 bacterial infection salmonella typhi
 Transmission
 Contaminated food and water by faces
 Symptoms
 A very high fever 39-400C
 A painful abdomen
 Sore throat and headache
 Constipation or diarrhea
 An enlarged spleen and liver
 Untreated thyroid, becomes delirious, weak, exhausted and may die

 Control and prevention

 Used antibiotics
 Need plenty of fluids to replace the one lost
 High calorie meals to help mineral and energy they have lost
 Carful hand washing after toilet

Sexually transmitted disease (STD’s)

 STD’S are transmitted through sexual contact
 They are also known as venereal disease
 The commonly known STD’S are gonorrhea, cancroids, syphilis, HIV/AIDS

5) Gonorrhea
 Caused
 Bacteria called Neisseria gonorrhea
 Transmission
 Spread through unprotected sex
 Mother to child during birth
 Symptoms
 In men the symptoms of gonorrhea are
 Burning sensation during urination
 Yellowish or white discharge from penis
 In women mostly asymptomatic, but sometimes it may show
 Discharge from vagina
 Burning sensation while urination
 Untreated gonorrhea in pregnant women ,may result in blindness of her
baby
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  Control and prevention
 Respect ABC rule
A; abstain B; be faithful C; use condom
 Visit clinics or hospitals
6) Syphilis
 Cause
 A bacterial infection called Treponema palladium
 Transmission
 unprotected sexual intercourse
 congenital syphilis transmitted from mother to child
 Symptoms three major stage of symptoms
 Primary stage (the first six weak)
 Painless sore at the site of infection
 Swollen gland
 Secondary stage ( occur sex wreaks after primary infection)
 Tiredness Hoarseness
 Fever Loss of appetite
 Sore throat Patch hair loss
 Headaches Swollen gland
 Third stage (late syphilis)
 It appears after years may cause severe irreversible problems
 Involves illness of the skin , bones, central nerve systems
 Transmitted from pregnant women to her baby and may cause death and
deformity

 Control and prevention

 Respect ABC rules
 Visit clinic and hospitals
 Blood test for pregnant women
 If you are infected, avoid sexual contact

7) Chancroids
 Cause
 A bacteria called Hemophilus ducrey
 Transmission
 Unprotected sexual intercourse
 Symptoms
 First stage
 Ulceration on genitals, particularly on penis
 Bleeding of ulcer and bursting of pus
 Second stage

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  Swollen glands which are filled with pus
 Permanent loss of penis
 Control and prevention
 Taking effective dose of antibiotics
 Respect ABC rule
 good genital hygiene , male circumcision

8) HIV/A IDS
 Acquired Immune Deficiency Syndrome (AIDS) is the medical term for a combination of
illnesses that result when the immune system is weakened or destroyed
 Caused by Human Immunodeficiency Virus (HIV), a virus that attacks the immune system,
making the sufferer susceptible to other diseases.
 Transmission
 Sexual intercourse with infected person.
 From infected mother to her baby in the womb, during birth breastfeeds.
 Through Infected blood transfusion
 Fight against HIV/AIDS
 Education on HIV/AIDS (transmission and prevention)
 Avoid stigma and discrimination
 Encourage people to take voluntary HIV-test

 The lymph system and Immune system

 Immune system is based in lymph system which spreads throughout the body.
 The lymph vessels carrying a fluid called lymph
 Lymph defend the body against disease by producing lymphocytes
 Lymphocytes produce antibodies against invading pathogens.
 The lymph glands filter out bacteria and other microbes from the lymph to be ingested
by the phagocytes.
 Enlarged lymph glands are a sign that the body is fighting off an invading pathogen.
 the main sites of the enlarged lymph glands
 Axillary lymph nodes (in armpit)
 Cervical lymph nodes (neck)
 Mesenteric lymph nodes (gut)
 Inguinal lymph nodes (in groin)

 How does HIV attack the immune system?

 There are two main types of white blood cells in the immune system.
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  T-cells bind to foreign antigen and destroy it.
 B-cells make antibodies which bind to the antigen and destroy it.
 Make memory cells which ‘remember’ how to make the right antibodies if
the same foreign antigen turns up again
 HIV attacks the T-cells of the immune syste

Summery
No Disease Caused by Root of transmission
1 Tape worm Parasitic flat worm Eating raw or under cooked meat
2 Tuberculosis Bacteria, Mycobacterium tuberculosis Air droplet /aerosol/
3 Malaria Protozoa, plasmodium Bite of anopheles mosquito
4 Cholera Bacteria, Vibro cholera Contaminated food and water
5 Typhoid Bacteria, Salmonella typhi Contaminated food and water
6 AWD Bacteria, Virus, Protozoa Contaminated food and water
7 Gonorrhea Bacteria, Neissaria gonorrhea Unprotected sexual intercourse
8 Syphilis Bacteria, Treponema palladium Unprotected sexual intercourse
9 Chancroid Bacteria, Hemophilus ducrey Unprotected sexual intercourse
10 AIDS Virus, Human Immune Virus Unprotected sexual intercourse

UNIT 5
CLASSIFICATION

5.1. PRINCIPLES OF CLASSIFICATION

 The importance of classifying organism

 To simplify the study
 Try to understand how life originated
 To bring order out of chaos or confusion

 The classification system

 Species a group of organism that can breed successfully with one another to
produce fertile offspring
 Classification is the system of groping organism based on similarity and
difference
 Taxonomy a branch of biology which is concerned with classification of organism

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  Dichotomous key/ identification key/the a type of key used to classify living
organism based on making a choice between two alternatives
 Groups of living things into categories is called taxa
 The main taxonomic categories are;

 Largest; kingdom Smallest; species

 Kingdom divided into phylum , phylum divided into class
 Similar phylum group into kingdom, similar class group into phylum
 Species contain one type of organism, which have all their main feature in common
 Naming of living things
 Linnaeus was the first biologist who introduce binomial system of classification
 Binomial system of naming organism has two names
 The first name genus while the second name species both name derived from latin
 The genus name starts in capital latter and the species name in small latter
 The scientific name should be underlined or printed in italics
 Examples
 human beings ; Homo sapiens Homo, genus name sapiens, species name
 Dog; Canis familiaris Canis, genus name and familiaris species name
 House flies; Musca domestica
 Domestic cat; Felies domestica Review Question p.177

5.2. THE FIVE KINGDOM

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 In modern classification, there are five kingdoms namely;
Kingdoms General characteristics
1 Monera Unicellular prokaryotic organism E.g. Bacteria
2 Protista Unicellular eukaryotic organism E.g., algae and protozoa
3 Fungi Unicellular or multicellular organisms E.g. yeast and mucor
4 Animalia Eukaryotic without chlorophyll E.g. man
5 Plantae Eukaryotic chlorophyll containing organism. E.g.
angiosperm

I. Kingdom monera
 Are unicellular prokaryotic, that do not have membrane bonded nucleus
 Include all bacteria and blue green algae
 Bacteria act as pathogens
 Mycobacterium tuberculosis which cause tuberculosis
 Haemophilus ducrey that cause chancroid
II. Kingdom protista /protoctista/
 Unicellular and eukaryotic ,that do have a nucleus
 They live as a parasite and free living
 Some protista cause a serious disease
 Plasmodium falciparium which cause malaria
 Entamoeba histolyca, which cause amoebic dysentery
 Trypanosoma, a blood parasite that cause sleeping sickness
 Dianoflagelates , which cause bioluminescence

III. Kingdom fungi

 Eukaryotic, unicellular and heterotrophic organism
 Have cell wall made up of chitin but lack chlorophyll
 Mood of nutrition
 Saprophytic fungi feed on dead materials. They act as decomposer which
have a role in recycling of nutrients .E.g. Rhizophus, Mucor, penicillium
 Mutualism fungi; live in close association with other organism and both
benefit. E.g --Lichens an association of fungi and green algae
--Mycorrhizal an association of a fungus a root of plant
 Parasitic fungi; Feeding on living organism. Candida albicans cause trush,
Tinea pedis cause athlete’s foot

IV. Kingdom plantae

The main characteristics of plant
 Have eukaryotic cell
 Multicellular organism
 Contain chlorophyll and carry out photosynthesis
 Predominantly land dwelling
 Have cuticle to prevent water loss

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  Four important division ;
 Bryophytes,
 pteridophyta,
 Gymnosperm,
 Angiosperm
 Division bryophytes (mosses and liverworts)
 They are the simplest land plant
 They have no true root, stem and leaf, they have thallus body.
 They are non-vascular ( no xylem and phloem)
 Have a simple leaves
 Have a simple root like structure
called rhizoid which is used for absorption of nutrient
 Commonly found in rainforest and high altitude
 Division pteridophyta (Ferns)
 Have well develop root, stem and leaf
 Have horizontally growing stem called rhizomes
 The fern leaf is called fronds
 Reproduce by spores found in sori, at the back of leaf
 Have vascular tissue (xylem and phloem)

 Spermatophyte (Seed bearing plant)

 Have well develop root stem and leaf
 Have well develop vascular tissues
 Male gametes contained in a pollen
grains and the female gamete found in the embryo sac
 The product of fertilization in sexual reproduction is seed
 Spermatophyte divided into two division
 Division gymnosperm
 Division angiosperm
Division Gymnospermae (conifer, Non flowering plant)
 Seed are not enclosed in a fruit
 Have small needle shaped leaves with a weak waxy cuticle in order to
 To reduce water loss, minimizes damage by excess heat or cold
 They are evergreen
 Reproductive organ male and female cones
 Do not have flower and fruits
 E.g. pinus , yabesha tid,

Division Angiosperm (flowering plant)

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  Reproductive organ flower
 Seed enclosed in fruit
 Well develop xylem and phloem tissue
 Angiosperm divided into two sub class based on the number of cotyledon in their seed
A. Monocotyledon (monocot)
B. Dicotyledons ( dicots)

Monocots Dicots
The embryo has single seed leaf The embryo has two seed leaf
Parallel venation of leaves Net (reticulate) venation of leaves
Leaves are generally long and thin Leaves are often relatively broad
Vascular bundle are scattered Ring of vascular bundle
Generally do not reach great size ( absence Same dicot reach great size( have vascular
of cambium) cambium0
Often wind pollinated Often insect pollinated
E.g. maize, grass, Orichids E.g. pea rose, bean, mango, jacaranda

V. Kingdom animalia
 Multicellular ,eukaryotic, ,heterotrophic organism
 Feed on other organism
 Exhibit locomotion, move their body from one place to another
 The cell do not have cell wall
 The major phylum in animal kingdom

Animal phylum Representative examples

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 Porifera (sponges) Sponges
Coelenterate (cnidaria) Sea anemones, hydra, jellyfish, Coral
Platy helminthes(flat worm) Planaria ,tape worm, liver flukes,
Nematodes(round worm) Ascaris,
Annelids segmented worm) Earthworm, leech
Mollusca Soft bodied animal) Octopus, squid, Slugs, Snail
Echinodermata (spiny skinned Starfish (Asteris),sea cucumber, sea urchin
animal)
Arthropod(joint footed animal) Insects, arachnidan, crustacean, diplopods ,
Chilopods
Chordate Pisces, amphibians, reptiles, aves, mammals

1. Phylum Porifera (sponges)

 No tissue organization
 Single body cavity
 Numerous pores in body wall
 They are hallow filter fidder
 Adult are sessile; permanently attached to the surface of sea fig. sponges
 Co-ordination supported by
calcareous spicules

2. Phylum Coelenterates (Cnidarians)

 Have two body layer
 Have only one opening mouth
 Radial symmetry
 Mouth supported by tentacle,
for capturing prey fig. hydra fig. jelly fish
 Have stinging cell their tentacles for poisoning or immobilizing prey

3. Phylum Plathelments - flat worm

 Have no body cavity
 Have flat body shape
 Are bilateral shape
 Bilateral symmetry
 They are hermaphrodites
 Have mouth but no anus
fig. Planarian
4. Phylum Nematodes - Round worm
 Have narrow, thread like body
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  Bilateral symmetry
 Body not segmented
 No circulatory system
 Complete digestive system with mouth and anus
5. Phylum Annelid- Segmented worm
 Have closed blood circulatory system
 They are hermaphrodite
 Bristle like structure called chaetae,
help them to move
 Most are free living
6. Phylum mollusca -Soft bodied animal
 Have soft body
 Body not segmented
 Most have shell
 Body divided into head, foot and Visceral mass, Breath through gills

7. Phylum Echinodermata- spiny skinned animal

 Have exoskeleton Have many tubular feet
 Body covered with spin Are radial symmetry
8. Phylum arthropods – joint footed animal
 Have jointed appendage
 Have an exoskeleton made of chitin, which is used;
 Prevent water loss
 Limits their growth
 Have segmented body
 Have well develop nerve system
 Complete gut from mouth to anus
 The most varied animal on the earth
 Divided into a number of five class;
1) Class insect
2) Class crustacean
3) Class chilopodes - centipedes
4) Class Diplopod- millipedes
5) Class Arachnidan

Class Class Class Class Class

Insects Crustaceans Chilopoda Diplopods /Arachnidan/
/Centipedes/ /Millipedes.
 Tree body  body two parts  flat body  cylindrical  two body parts
parts Cephalothoraxes  bright body Cephalothoraxes
 Head, thorax, (fused head & colored body  dull colored Abdomen
abdomen thorax), Abdomen  few segment body  with no
 3 pair of  body covered  1 pair of limb  have more antenna
jointed by Carapace per segment segment  4 pair of legs

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 Legs  four pair  Carnivores  2 pair of limb  have simple
 1 or2 pair of jointed leg  poisoning per eyes
wing  two pair of claws segment  E.g. Spider,
 have a pair of antenna and  For  Herbivores tikes,
antenna simple eye paralyzing  have claws for scorpions,
 one pair of  E.g. lobsters, prey biting and mites
Compound eye wood lice, chewing prey
 E.g flies, water flies
beetles

9. Phylum chordate
 Have notochords
 Have hallow nerve cord
 Have gill slits later replaced by lungs and
gills Bony fish Cartilaginous fish
Vertebrates Have bony skeleton Have cartilaginous
 Invertebrates make up 99.9% of animals skeleton
 Have endoskeleton made of bone and Have round shaped Have scale but not
scales round
cartilage
Opercula covering No opercula but have
 Have closed blood circulatory system
the gills gill slits
 Have well developed nerve system
 Two pair of limb and kidney as execratory Have homocerical Have heterocerical
organ Tail( even size fin) Tail (different size)
 Phylum chordate divided into 5 classes Usually smaller size Usually larger size
1. Class Pisces-the fish E.g. Tilapia, Nile E.g. Sharks, skates,
 Are aquatic perch, catfish, cod, rays
 Ectothermic
 variable body temperature
 need environment to regulate their body temperature
 Have gill
 Have fins
 Lay unfertilized egg
 Divided into two sub class
 Teleosts - bony fish
 Elasmobranches- cartilaginous fish
FROG TOADS
2. Class amphibian
Has smooth skin Has rough skin
 Live on land and water
Has a moist skin Has a dry skin
Has more webbed feet Has less webbed feet
50 | P a g e Has bright colored Has a dull colored body
body
More streamlined body Less streamlined body
Has extra-long hind Has hind legs that are not
legs extra long
  Have moist skin (respiratory surface)
 Lay unfertilized egg in water
 Larva (tadpole) live in water
 The adult live both on land and water
 Are Ectothermic
 E.g. frogs, toads, newts, salamander
3. Class reptiles
 Have dry skin with scales
 Gas exchange take place in the lung
 Developed internal fertilization
 Lay egg in land in a leather shell
 Gill slits only seen in embryonic stage
 Have no external ears
 Are ectothermes E.g. snake, Crocodiles, Lizard
4. Class aves- birds
 Have feathers
 Fore limbs are adapted as wing
 Lay fertilized egg covered with shell
 Have beaks
 Have light skeleton , which make easier to fly
 Are endothermic-constant body temperature

5. Class mammals
 Feed their young with Sub division of class mammals
milk Egg laying Marsupials Placental
 Have diaphragm mammals mammals
 Have 4 chamber heart
 Lay egg  Produce immature  Higher
 Body covered with hair
 Have sweat gland  E.g. duck young mammals
 Have well developed billed  which are  Produce fully
brain mammals nourished milk in developed
 Are endothermic poach young
 E.g. rats, monkeys,  kangaroo,  Nourished
dogs, human koalbeer , opssum milk from
mammary
gland
EXERCISE  Cats, caw,
1. In the scientific name Canis man
familiaris the word canis
stands for?
A. Genus name B. species name C. family name D. kingdom
2. Fish, Amphibian, reptiles, birds and mammals are grouped in the:
A. phylum B. Order C. family D. class
3. Which of the following is the segmented warms?

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 A. leech B. hook warm C. Ascaris D. tape warm
4. Dorsal nerve tube is a feature of;
A. Echinodermata B. Mollusks C. Arthropod D . Chordata
5. Which of the following group of animals has varied animal on earth?
A Arthropods B. chordata C. mollusks D. Echinodermata
6. Which major groups of plant kingdom is best characterize by having vascular tissue and
reproduce by spores?
A. Ferns B, conifer C. mosses D. Angiosperms

UNIT 6

ENVIRONMENT

 Environment; an organism’s home and its surrounding

 Ecology ; deal with the study of environment
 It concerned with the interrelation ship of organism with each other and with its
environment
 It deal biological organization (organism population community ecosystem
biomes biosphere) above organism
 Ecology do not deal with individual organism

5.3. ECOSYSTEMS

 A life supporting environment

 All animals and plants that live in an area along with that thing that affect them
 Composed of biotic (living) and abiotic ( non-living) components
 Abiotic components
 Non living component of the environment
 Includes amount of sun light, amount of rainfall, temperature, type of soil and
rocks, level of oxygen, water. Wind
 Biotic component
 The living organisms within an ecosystem which affect the ability of an organism to
survive there
 Includes disease and parasites, predator numbers, food availability, competition
 Competition; animal compete for food, water, , territory, mate
 Plant compete with each other for light, water and nutrient

5.4. FOOD RELATIONSHIP

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  Based on the mode of nutrition organism divided into two
1. Autotrophs
 Organisms that can make their own food
 Autotrophs can be divided into;
 Photo autotrophs (light feeders); a group of organisms that use sun light as
primary source of energy to synthesis their own food E.g. Green plants because
of making carbohydrate they are known as producers
 Chemo autotrophs; a group of organisms that release energy from simple
chemical reaction. E.g. nitrifying bacteria, green sulfur bacteria

2. Hetrotrophs
 Organism that cannot synthesis their own food. they are called consumer
 Feed on other organism
 Can be divided as herbivores, carnivores, omnivores and decomposer
 Herbivores; animal that feed on vegetation. E.g. caw, giraffe
 Carnivores; animal that feed on animal flesh. E.g. Lion , cat
 Omnivores; animal that feed on b plant and animal flesh. E.g. human ,rat
 Decomposers; organism that break down dead bodies. E.g. bacteria, fungi
 Food chains
 Is a simple and direct feeding relation ship
 Involves the transfer of energy and nutrient from one organism to another
 Energy flow from producer to consumer. Producers Consumers
 Producers; first trophic level. Green plant
 Primary consumer; second trophic level. Herbivores and omnivores
 Secondary consumer; third trophic level. Herbivores and omnivores
 Tertiary consumer; forth trophic level. Carnivores
 Omnivores can occupy primary and secondary consumer
 Decomposers are found at the end of food chain
 Grass Caw human
 Grass; first trophic level and producer
 Caw; second trophic level and primary consumer
 Human; third trophic level and secondary consumer
 Aquatic food chain start microscopic photosynthetic organism known as phytoplankton
 phytoplankton zooplankton fish human

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 Fig, food chains fig. food web

 Food web
 Is a complex feeding interrelation between organism that consists many food chain
 The actual feeding relationships in a community
 How many food chains can you construct in this food chain?

Ecological pyramid
 Is a geographical representation designed to show the bio-productivity At each trophic level in a
given ecosystem
 Three type of ecological pyramid
1. Pyramid of biomass
 Biomass; the total amount of organic matter
 Pyramid based on the dry mass of tissue of organism at each trophic level
 The total amount of biomass decrease as we go from producer to consumer
 At each trophic level biomass is lost by; BIRD

 Heat from respiration LIZARD

INSECT
 Urine, faces and to provide energy
Grass
Limitation
Gives equal value to tissue which differ in
Chemical Composition and energy value

2. Pyramid of number
 Pyramid made based on the number of organism in each trophic level.
 In most ecosystem the number organism decrease from producer to consumer

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 Sometimes pyramid of number
Fox Fleas Does not accurately reflect
Rabbit Ecological pyramid
Rabbit
Grass
Grass
3. Pyramid of energy
 Pyramid drown based on the amount energy produce at each trophic level
It gives the most accurate representation ecological pyramid
Fleas
Review question P. 211
Rabbit
Grass

5.5. RECYCLING IN NATURE

 Nutrient( carbon, nitrogen, sulfur, and water) recycled in an ecosystem between organism
and environment

 Decomposers ( bacteria and fungi)play a huge role in recycling

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  Energy never recycling in an ecosystem
Nitrogen in air
The nitrogen cycle
N2 Is the part of protein, amino acid, DNA ATP
1. Plant absorb nitrate from the soil Animal
and make amino acid and protein
Ammonia
2. Animal obtains nitrogen by feeding NH3+ Nitrate
of plant Plant NO3
-
3. Putrefying /amonifying/ bacteria; convert
protein in dead bodies and their execratory
product into ammonia
Nitrite
4. Nitrifying bacteria ; ammonium ion is oxidize into nitrates -
in two process 4a. Nitrosomonas 4b. Nitrobacter NO2
5. Denitrifying bacteria; convert nitrates in soil into elemental nitrogen, reduce the amount of
nitrogen in the soil
6. Nitrogen fixing bacteria; convert elemental nitrogen into ammonium ion
Legumes (Pea, bean); in the root nodules of many legumes plant have symbiotically nitrogen
fixing bacteria called rhizobium, which have the ability to fix nitrogen in the soil.

Carbon cycle
 Important process in carbon cycle
a) photosynthesis; remove the amount carbon dioxide from the cycle
b) respiration;
c) combustions; increase the amount of carbon dioxide in the atmosphere
d) decomposition;

 Ozone; layer of the atmospheres that protect the earth from harmful ultraviolet light
from the sun
 Global warming; is the rising of temperature on earth’s surface as a result of accumulation of
greenhouse gas like carbon dioxide and methane
 Carbon dioxide CO2 ; Increase as a result of human activity such as
 Combustion Burning of fissile fuel, Deforestation, Respiration
 Methane; It is increased in the atmosphere as a result of
 Growth of rice in swampy condition review question
 Digestive activity of cattle produce methane P.217

5.6. ADAPTATIONS

 Adaptations; features of organism develop which make it possible for them to survive in
a particular habitat
1) Animal in cold climate
 Reduce surface area to volume ratio, larger size like seal, whales and polar beer in
order to prevent heat lost.
 Small extremities like ear to reduce heat loss. E.g. polar beer
 Thick layer of fat under skin (blubber) to store more internal heat

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  Have thick fur coat on the outside will insulate an animal

2) Animal in dry climate

 The biggest challenge of animal live in desert
 Coping with the lack of water
 The rise of core body temperature
 Large surface area to volume ratio (small size) to loss more heat
 Obtains water from the food they eat
 Lot of sweat produced in order to coal the body
 Active in early evening and late evening
 Big ear like fennec fox to loss heat faster
 Thin fur coat in order to loss heat

3) Plant adaptation in desert

 Deep growing root system to absorb water
 Thick and fleshy stem, root to store more water
 Sunken and few stomata to reduce the amount of water loss
 Thick waxy cuticle to reduce the amount of water loss
 Leaves are reduce to reduce transpiration
 Have curled leaves; these reduce the surface area of the leaf and trap moist air
around the leaf.

 Camouflage; is the ability of an animal to blend its color into the surrounding
environment to avoid detection.
 Important both to predator(the prey does not see them coming) and to prey ( they
cannot be seen)
 Arctic fox change the grey and browns of their summer coat into pure white in winter
Unit exercise End unit
Choose the best answer questions
1. All non living things in an ecosystem are called? p.225 and P.
A. Abiotic component B. Biotic components C. Population D. ecosystem 222
2. A certain plants requires moistures, CO2, light, and minerals. This shows that living organism
depend on;
A. biotic factor B. Abiotic factor
C. symbiotic relationship D. carnivore and herbivore relationship
3. Which is a biotic factor operating in an ecosystem?
A. A climate in a given region C. the amount of nitrogen gas in the air
B. A carnivore that consume other animal D. the rate of flow of water in the river
4. A cactus is adapted to service in a disert condition. Which of the following is true?
A. Flower only open during the heat of the day
B. The leaves are spin to prevent water loss
C. the leaves are spin to prevent eating by animals
D. the swollen stem stores water
5. Organism that obtain nutrients by breaking down dead and decay plants and animals are called;
A. Omnivores B. Decomposers C. producers D. scavengers

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6. The total amount of living tissue within a given trophic level is called?
A. Organic mass B. Energy mass C. Trophic mass D. Biomass
7. The relationship between two species where one benefits while the other unaffected is called;
A. Mutualism B. parasitism C. Commensalism D. Predation

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