Biology Notes



Is a scientific study which deals with living things or organisms. Living things or organisms mean:

  1. Animals.
  2. Plants.

Biology is derived from two Greek words:

Bios- Life.

Logos- Study.

Note:All living things are made up of cells. Unicellular organisms -> Single celled e.g. Amoeba are multicellular organisms with many cells.

A cell: Is a single unit of life.

Cell -> tissue -> organ -> system -> organism.


Characteristics of living things.

  1. Movement: change of position or posture.
  2. Nutrition: food for growth and energy.
  3. Sensibility and irritability: response towards or against a stimulus.
  4. Respiration: break down of food in order to release energy.
  5. Excretion: removing waste products from the body.
  6. Growth and life cycle: the increase of size and shape and finally death.
  7. Reproduction: the increase in number.


Note the following:

  1. Zoology- study of animals.
  2. Botany- study of plants.
  3. Mycology- study of fungi.
  4. Bacteriology- study of bacteria.
  5. Anatomy- study of the structure of an organism internally.
  6. Physiology- study of how the living matter functions.
  7. Taxonomy- study of scientific classification.
  8. Parasitology- Study of parasites or parasitism.


Simple structure of animal and plant cell.

Animal cell


Plant cell



Functions of cell parts.

  1. Nucleus- Controls all the activities of the cell.
  2. Cytoplasm- Is a cavity in which all the organelles part.
  3. Cell membrane- Protects or covers the cell, also allows the material in and out of the cell.
  4. Cell wall- It is made of cellulose which protects and gives shape to a plant.
  5. Chloroplast- Is a greenish part of a cell which contains a pigment called chlorophyll which traps solar energy and makes use of it in manufacturing of its own food, a process known as photosynthesis.
  6. Vacuole- Is filled by a liquid called cell sap which exerts a pressure on the cytoplasm to make a cell wall firm and strong.



Plant cell Animal cell
1. Has definite shape. Has no shape (irregular)
2. Has a cell wall made up of cellulite. Has no cell wall.
3. Has a large permanent vacuole. Has a small and temporary vacuole.
4. Has chlorophyll. No chlorophyll.

The importance of studying biology.

  1. Man is a living organism so studying biology helps him to understand himself better.
  2. We have to learn how animals and plants grow, because they provide us with food, clothes, and shelter.
  3. The knowledge of this subject enables man to conserve his environment, because man has been so distinctive to life than any other creature.
  4. We care for animals and plants by treating their diseases by observing at their causes, symptoms and mode of transmissions.
  5. We become more curious by asking questions like when did life originate, how do plants feed? Etc. We get employed e.g. Doctor e.t.c.

The relationship between Biology and other related science subjects.

  1.  Biology and Chemistry.

Biology tells us about living things and Chemistry tells us about the composition of living things.

2. Biology and Physics.

In Biology we learn names and shapes of different organisms and in physics we describe the quantity of matter in organisms.

3. Biology and Mathematics.

An organism can be measured to check body temperature, blood sugar, obesity, blood pressure etc. All these are done due to mathematical skills.

4. Biology and Geography.

Geography provides the information about the home of living things.




The following are the methods of studying Biology.

1.Observation (Identification of a problem.)

This process involves the following sense organs: eyes, ear, nose, skin and tongue. But the tongue is rarely used because some of the chemicals are poisonous.


Involves a guess work so it can be regarded as a biological acceptable explanation of what has been observed unless more proof takes place.


Is designed to prove or disprove formulate of hypothesis. This work is done in the laboratory.

4.Observation and data recording.

At this level, we observe and record important events which appear to be important or meaningful.

5.Interpretation of data.

At this level obtained are clearly explained in relation to the purpose of the experiment.


At this level, the researcher is either confirming or rejecting the hypothesis formulated.


Measurements:During experiments in order to observe clearly an instrument called microscope is used.


Microscope: Is an instrument used to magnify images of near objects to a large size.


Parts of a microscope.

  1. Mirror- It directs light to the object.
  2. Stage- The object to be observed is placed.
  3. Adjustment- Knobs, coarse and fine adjustment are used to obtain a clear object of moving them up and down.
  4. Eye piece- Is fitted with magnifying lenses, so at this level an object is enlarged in order to be observed clearly.
  5. Objectives- Is also used for magnifying lenses because objectives vary in their magnification powers.

The power is indicated on the objectives as X5, X10, X40 etc.

Note- X means multiply.




Laboratory is a room or a building specially designed for biological experiments.

Types of laboratories.

  1. School lab.
  2. Hospital lab.
  3. Industrial lab.
  4. Pharmaceutical lab.
  5. Atomic lab.

A good lab must have:

  1. Enough supply of oxygen.
  2. Electricity.
  3. Water.
  4. Large windows.
  5. Quiet and safe place.
  6. Fire extinguisher.

Safety in Biology lab.

When an experiment is done, it should never be assumed to be completely harmless. Even the apparently simple experiments should be regarded as a potential source of danger.

Lab rules.

  1. Don’t handle any chemicals without instructions from the teacher.
  2. Any accident must be reported immediately, so first aid should be provided.
  3. Put off flames which are not in use.
  4. When heating, never put yourself or towards others.
  5. Hold test tubes using holders when heating.
  6. Never taste chemicals.
  7. Keep flammable substances away from flames.
  8. Dispose all specimens and chemicals which are already used.
  9. Don’t play or run in the lab.
  10. Don’t eat and drink in the lab.

Warning signs.

Toxic- It can poison you.

Image result for TOXIC WARNING SIGN












Common tools used in studying Biology.

  1. Microscope.
  2. Hand lens.
  3. Thermometer.
  4. Dissection tools.
  5. Test tube.
  6. Test tube holder.
  7. Test tube rack.
  8. Bunsen burner.
  9. Mounted needle.
  10. Round bottom flask.
  11. Flat bottom flask.
  12. Cover slips.
  13. Spatula.
  14. Droppers.
  15. Sliders.
  16. Forceps.
  17. Scalpel.

Common chemicals used in Biology.

  1. Iodine.
  2. Glucose.
  3. Million’s reagent.
  4. Distilled water.
  5. Benedict’s Solution.
  6. Sucrose.
  7. Enzymes.
  8. Starch.
  9. Sudan III dye.

Specimens used in Biology.

  1. Grasshopper.
  2. Fish.
  3. Snakes.
  4. Frog.
  5. Plants.
  6. Fruits.

Models used in studying Biology.

  1. Heart.
  2. Skeleton.
  3. Lungs.
  4. Human body.
  5. Kidney.



First aid.

It is an immediate and temporary care or help or treatment given to an injured person before taking him to the hospital.

Importance of First aid.

  1. Saves life.
  2. Reduces pain.
  3. Reduces shock.
  4. Brings hope and encouragement.
  5. Reduces fear of death.

A First Aid kit.

Is a small box or instrument in which all medical facilities for conducting First aid are kept.

Components of first aid kit.

  1. A pair of scissors.
  2. Rolls of adhesive tape.
  3. Assorted bandages.
  4. Sterilized cotton wool.
  5. New razor blade.
  6. Jar of petroleum jelly.
  7. Soap.
  8. Gentian violet solution.
  9. Antibiotic solution.
  10. Pain killer’s e.g. Panadol.
  11. Methylated spirit.
  12. Clean water.

First aid given to victims of:

  1. Snake bites, scorpion, spiders and hairy caterpillars.
  2. Fainting.
  3. Excessive bleeding.
  4. Burns.
  5. Cuts, scrapes and wounds.
  6. Oral poising.
  7. Drowning.
  8. Heart cramps.
  9. Muscle cramps.
  10. Nose bleeding.
  11. Discoloration.

Safety in our environment.

Environment is the surroundings in which living things live. It includes natural world such as land, air and water in which people, animals and plants live. Humans have invented methods to protect themselves against the diseases in their environment.

Personal hygiene and good manners.

-Personal hygiene is defined as the measures each individual employs to keep in good physical precautions.

-Good manner is a way of behaving that is considered acceptable in your family.


Principles of personal hygiene and good manners.

It integrates the following:

a.) Hand hygiene.

Hands should be washed especially after contact with an animal, after using a towel, before eating or after touching a person likely to be infected. A good routine for washing hands should include:

  • Wet hands with warm water.
  • Remove any jewelry or any metal tool if any.
  • Wash hand vigorously for 30 seconds with a suitable soap.
  • Clean well the nails to remove any germs.
  • Rinse hands and dry them on a clean towel.

b.)  Bathing.

A dirty body is a hotbed for developing germs. Dust, warmth, sweat and other secretions are all factors which encourage germs to multiply. It is recommended to bath at least twice a day, and oil properly. Keep your hair short and comb to maintain its cleanliness.

c.) Oral hygiene.

Attention should be paid to eliminate food particles. To avoid dental plague, ensure daily gum care as well as visiting the dentist regularly. Adhere the following to maintain oral hygiene:

  • Brush teeth after each meal twice a day in an effective manner.
  • Use good clean and quality toothpastes.
  • Rinse your teeth well.
  • Do not share toothbrush and utensils.
  • Avoid putting objects or figures in the mouth.
  • Brush up and down in a light circular motion, in front and behind and across the top of the teeth for at least 3 minutes.
  • Do not take in sugar and sweets because they encourage dental causes.

d.) Nasal hygiene.

Nasal secretions are highly contaminated and a running nose or sneezing is a important source of germs disseminations. Frequent nose blowing to clear the nostrils using paper tissues is done as follows:

  • Place tissue over the nose.
  • Close one nostril with one finger to blow the other one.
  • Repeat until the nostril is clear.
  • Do the same with other nostrils.
  • Wipe the nose using soft tissue.
  • Dispose the germ laden tissue properly.

e.)  Cleaning clothes and shoes.

Clean clothes, underwear and shoes should be worn and changed daily.

  • Wash and iron clothes properly.
  • Avoid sharing clothes such as socks, t-shirts etc.
  • Bedding should be changed once after every two days.
  • Always wear clean shoes.

f.) Doing physical exercise.

How does physical exercise help us live longer and better?

  • Helps us feel good.
  • Strengthens the heart.
  • Lowers blood pressure.
  • Lowers blood cholesterol.
  • Strengthens bones.
  • Lifts depression, relieves anxiety and stress.
  • Helps maintain desirable weight levels.
  • Improves circulation that clears the mind.

g.) Environmental cleanliness.

Proper cleaning of the house or room is very important to keep you healthy. It includes:

  • Cut the grass short and sweeping.
  • Remove all the stagnant water (breeding place for mosquitoes)
  • Always use toilet in a proper way.
  • Prepare your meal in a hygienic way.
  • Keep all litter and rubbish in a well secluded area.

In summary, the following are eight personal hygiene practices:

  1. Do not litter.
  2. Spit, cough and sneeze into a tissue.
  3. Wash hands with soap frequently.
  4. Keep private and public toilets clean.
  5. Bag your rubbish and place everything in a bin.
  6. Keep places free and clean of pests.
  7. Eat healthy food and exercise regularly.
  8. Check health and avoid crowded places.


What is the behavior of an individual with good manners?

Good manners should be acceptable in one’s culture.

Tanzanian culture, good manners include:

  1. Respecting yourself and others.
  2. Greeting elders.
  3. Loving all people.
  4. Avoid risk behaviors e.g. Alcoholism, smoking etc.
  5. Proper dressing.
  6. Responsible hardworking individual.
  7. Obey laws, rules, and guide lines.

Importance of personal hygiene and good manners.

It is very important to maintain personal hygiene and good manners because:

-They maintain health.

-All individuals will be respected and loved.

-All individuals will attain development.

-Avoid risk behavior.


Safety at home and school.

Safety is freedom, danger or injury.

Accident is an unexpected event.

Common accidents at home and school.



-Snake or insect bites.

-Electric shocks.

-Getting hurt by sharp objects.

-Bone fractures and dislocation.


a.) Poisoning.

Poison is a substance that causes injury or death when swallowed. It causes from different sources such as:

-Taking the wrong dosage of the prescribed medicine.


-Eating contaminated food or water.

-Rat poison, bleach, detergents etc.


b.) Burning.

It is the destruction or damage caused by fire or heat. Burning can be caused by:

-Gas leakage.

-Chemicals which are flammable.


c.) Insect or snake bites.

There are poisonous snakes and insects that are harmful. The poisons from black mamba, cobra, scorpions, bees and wasps are harmful to human health.


d.) Broken or dislocated bones and cuts.

The following can cause these:



-Car accidents.

-Getting hit by objects such as stones, bricks, wood, trees etc.


Ways of preventing accidents (Home and school.)

-Children must be protected from falls, burns, poisoning and electric shocks.

-People should learn road rules and traffic signs.

-Things which may cause accidents e.g. Such as kerosene, fuel, medicine, chemicals etc. should be locked.

-Extinguish all glowing residues before disposal.

-Use the right fuel for the right burners e.g. Do not use petrol for a kerosene burner.

-Cool a burner completely before you refill it with a liquid fuel.

-Electric circuits should be used as per instructions.

-Avoid spraying insecticides near flames as they are flammable.

-Wastes should be well and properly handled.

-Never keep kerosene, petrol or other poisonous substances in a soft drink bottle.


How to keep peace and safety at home.

-Toxic materials should be kept at a safe place.

-Smoking, drinking alcohol and other risky behaviors should be avoided.

-Furniture and cooking utensils should be well arranged.

-Food has to be well prepared.

-Decision making should involve the majority.

-Assertive behavior is essential.



5.Waste and waste disposal

Waste is any material without use, rejected, worthless or unwanted.

Waste comes from various activities such as:

-Construction wastes: Wood, metal, bricks, plaster, glass etc.

-Agricultural wastes such as pesticides, herbicides, empty containers.

-Industrial wastes – waste water, sludge, metals etc.


Types of waste.

  1. Solid waste.

Contain less than 70% of water.

They include household garbage, residual solids, mining wastes and oilfield cuttings.


  1. Liquid wastes.

Contain less than 1% of solids.

They include: wine, waste water, used chemicals and liquid industrial waste. They may contain a high concentration of dissolved salts and metals.


  1. Sludge.

This is a class of water between liquid and solid. They usually contain between 3% and 25% solids while the rest of the material is water-dissolved material.


  1. Gaseous wastes.

They include: Carbon dioxide, sulphur oxide, carbon monoxides, fluoride gas and nitrogen dioxide.


Waste disposal.

Waste should not be disposed in such a manner that the public interest is not impaired.

What is waste disposal?

It can be defined in different ways.

  1. It refers to processing and removal to final resting place or transfer to a place for reuse or recovery.
  2. It is the act of getting rid of unwanted items.
  3. It is the way of removing waste from the environment.

Principles of waste disposal.

Principles of disposing hazardous and non hazardous waste differ. Hazardous waste is of two types:

  1. Those that have common hazardous properties (ignitability or reactivity.)
  2. Those that have leachable toxic components.


Non hazardous wastes are those that pose no immediate threat to human health (and the environment.) (Household garbage.)

General principles of waste disposal.


  1. A little amount of food can be disposed as sewage.
  2. Food and yard waste should be separated from other garbage.
  3. Recyclable waste should be taken to a recycling area.
  4. Radioactive material should be separated from other garbage.
  5. Do not throw hazardous products in the drain, bury them or burn them.
  6. Use protective gear, gloves, clothes etc. when collecting waste.
  7. The sewage system water should be collected or piped to a central sewage plant for treatment before disposal.

Why not burn waste?

-May cause air pollution

-Some waste may burn to ash.

Why not bury waste?

-It may contaminate soil or water.

Proper ways of waste disposal.

Recovery-Turn materials into other categories e.g. cow dung -> biogas.

Recycling-Brings items to a stage where they will turn to other items.

Reduction of use-This is the basic principle of sound waste management.

Safe waste disposal-Waste should be disposed in a safe area.

Classification of waste based on recycling.

Waste falls into two main groups:

a.) Recycled waste:

Can be used to manufacture new products.

b.) Non recycled waste:

Cannot be used to manufacture new products.

Importance of proper waste disposal.

Waste should not be disposed in such a way that:

  1. Public interest is not impaired.
  2. Human health is not impaired.
  3. Animals and plants are not endangered.
  4. Water bodies and soil are not contaminated.
  5. Environment is unharmed eg. air pollution.


Thus proper waste disposal is important because:

  1. Reduces odour and bad smell.
  2. Encourages growth of useful organisms.
  3. Helps provide a pleasing atmosphere.
  4. Minimizes spread of infection.
  5. Minimizes likelihood of contaminating the soil.
  6. Reduces air pollution.


Effects of poor waste disposal.

  1. May cause toxic health effects.
  2. Improper storage may allow chemicals to leak causing chemical reactions.
  3. Water or soil may be contaminated.
  4. Burning may affect the ozone layer.
  5. It makes the environment ugly and unattractive.





Is a physical, mental and emotional well being of a person. Including freedom from hunger and anxiety.

Importance of good health.

  1. Removes tensions, frustrations, stress and anxiety.
  2. Work effectively and efficiently.
  3. Brings peace and security.
  4. Makes right and correct decisions.
  5. Removes diseases.
  6. Enables deliver healthy babies.



Is the ability of the body to fight against diseases.


Types of immunity.

  1. Natural immunity.
  2. Artificial immunity.


Natural immunity.

Is an immunity which an individual is born with.


Types of immunity:

  1. Active immunity.
  2. Passive immunity.


  1. Active immunity.

Is an immunity which develops as a result of exposure to pathogens e.g. when a person recovers from chicken pox or red eyes e.t.c.


  1. Passive immunity.

Occurs when antibodies are transferred from one person to another. This occurs naturally between the mother to an infant in breast feeding. This ends when the baby’s own immune system has matured.



Is a process of introducing vaccine into the body of an organism in order to increase the ability of the body to produce antibodies which fight diseases.



Is an antigen which triggers the body to produce antibodies.


Vaccine can be made of:

  1. Inactivated bacteria toxins.
  2. Killed microbes.
  3. Microbes.
  4. Viable but weakened microbes.


Examples of diseases which can be vaccinated:

  1. Rabies.
  2. Polio.
  3. Tetanus.
  4. Elephantiasis.
  5. Plague.
  6. Measles.

The cells and tissues involved in make up of the immune system includes:

  1. White blood cells.
  2. Lymph nodes.
  3. Spleen.
  4. Liver.
  5. Bone marrow.

Factors which affect body immunity:

  1. Lack of balanced diet.
  2. Pathogens e.g. HIV, cancer, T.B e.t.c.
  3. Drugs and chemicals.
  4. Old age
  5. Single cell anemia.
  6. Lack of vaccination e.t.c.
  7. Inability of the body to produce antibodies and WBC.

Infections and diseases.

Infection:Is a disease caused by an organism.

Pathogen:Is an organism which can cause a disease e.g. Virus.

Vector:Is an organism that transmits diseases causing micro organisms.

Host:Is an organism in which a pathogen lives e.g.. Human beings.

Parasite:Is an organism which lives in the body of another organism.

Disease:Is the body condition other than injury that interferes with the normal functioning in the body.


Contagious diseases.

Are diseases that are transmitted from one organism to another, e.g. Cholera, T.B e.t.c.

Causes of diseases.

  1. Malnutrition.
  2. Genetic disorders.
  3. Pollutions.
  4. Pathogens.

Types of diseases:

  1. Communicable disease.
  2. Non-communicable disease.

Other communicable disease require isolation (Quarantine) yellow fever, cholera, small pox, plague, SARS e.t.c.

Communicable disease.


  1. Epidemic:

Is a disease which spreads quickly and affect a large number of people in an area over a short period of time. E.g, measles, cholera, meningitis e.t.c.



  1. Pandemic:

Is a disease that affects the large area like several countries at a time, even a whole continent e.g. HIV/AIDS.



  1. Endemic:

Is a disease that is always found in a certain area continuously. E.g, Bilharzia, malaria e.t.c.


Non-communicable diseases.

They are non-infectious diseases that cannot be spread from one person to another.

They are caused by:

  1. Malnutrition.

It includes kwashiorkor, marasmus, scurvy e.t.c.


  1. Genetic abnormalities.

It includes sickle cell anemia, color blindness, albinism e.t.c.



  1. Hormonal imbalance.

It includes goiter, diabetes mellitus e.t.c.


  1. Pollution.

It includes asthma, cancer, allergy e.t.c.


  1. Drug abuse.


Common human diseases

  1. Typhoid.
  2. Plague.
  3. Meningitis.
  4. Cholera.
  5. Malaria.
  6. Schistosomiasis.



Epidemic diseases.

  1. Cholera:

It is caused by a bacterium called Vibrio cholerae. The bacterium affects the alimentary canal. It strikes areas where they are poor sanitary conditions and the water is poorly treated. It is epidemic during wars and famine.


When bacterium is ingested, it multiplies in the small intestines and invades the epithelial cells. When the bacteria die, they release toxins that irritate the intestine lining and leads to the secretion of large amounts of water and salts with the following symptoms:

-Diarrhoea and eventual vomiting.

-Extreme weakness.

-Body temperature drops.

-Loss of weight.

-Fast and shallow breathing.


Hygienic waste disposal and keeping food and water supplies clean are the control methods of this disease. Food should be well cooked and water must be boiled. Using toilets and washing hands frequently. One going to an infected area must be vaccinated.


Antibiotics will kill vibrios but it is more important to restore the salt and water balance of the body by drinking a solution made by dissolving one teaspoon of sugar and a pinch of salt in water. A vaccine made from the killed bacteria will give immunity for 3-6 months.





It is the infection of the membrane. There are three types of meningitis:

  • Bacterial meningitis- Caused by bacteria.
  • Viral meningitis- Caused by virus.
  • Tuberculosis meningitis- Caused by bacteria such as mycobacterium tuberculosis.

Symptoms:Bacterial meningitis is the most common associated with nausea, vomiting, headache etc.

Prevention:People carrying diseases should not mix with others.

Treatment:Early treatment is necessary for bacterial meningitis. Penicillin treats meningitis.



  1. Plague:

It is a bacterial disease called by bacillus bacterium called Pesturella pestis.

Symptoms:The person develops fever, swelling and inflammation of lymph nodes. Often the patient bleeds severely in many parts of body.

Transmission: Bubonic plague is caused by a bacterium and transmitted from infected rats to man by bite of fleas that feed on both.

Treatment: It can be treated using antibiotics such as tetracycline and streptomycin.


  1. Typhoid fever:

Caused by a bacterium known as Salmonella typhi. It is expelled from body by urine and stool.

Transmission:It spreads through contaminated food and water.

Symptoms:Body aches, fatigue, abdominal pains, diarrhoea, vomiting and constipation.


Since infection can occur only by ingesting the bacterium derived from the faeces or contaminated water, the long-term ways of control are to dispose human waste safely, ensure water is treated and keeping food safely. The hands should be washed frequently after using the toilet and before eating food so that intenstinal bacteria cannot be taken in with the food. Fruits should be wash using clean water.

Treatment:It is treated using an antibiotic called chloroamphenical.


Endemic diseases.

  1. Bilharziasis:

It is also called schistosomiasis. 200 million people around the world are infected with this disease. It is characterized by irritation in the rectum or urinary bladder. These parts become inflamed leading to a discharge of blood in faeces or urine. Damage and inflammation are caused by the escape of eggs from the infected organ to the outside world.


It is caused by schistosomes or blood flukes.

In Tanzania there are two types of schistosomes:


  1. Schistosoma haematobium– Causes urinary bilharzia.
  2. Schistosoma mansoni– Causes intestinal bilharzia.


-Weight loss.

-Appetite loss.

-Spleen becomes very large.

-Irritation in rectum and urinary bladder.

Transmission and life cycle.

Bilharzia worms have two hosts.


  1. In humans, the adult worms discharge eggs.
  2. Once in water, the eggs hatch into tiny ciliated larvae.
  3. The larvae seek appropriate snails and infect them.
  4. Asexual reproduction within a snail results in another type motile larvae.
  5. When a person bathes, the larvae penetrates the skin and blood vessels.
  6. In the tissues, the larvae migrates into the liver.
  7. Mature larvae leaves the liver.
  8. Larvae of Schistosoma haematobium find their way to the urinary bladder.


  1. Mature flukes in blood vessels of intestines.
  2. Blood flukes reproduce in human host.
  3. Eggs develop in water into ciliated larvae.
  4. Asexual reproduction in snail results in another type of motile larvae.
  5. Larvae penetrate the skin and blood vessels of human.

Control and prevention.

-Destroy breeding places of snails.

-Keep ducks in water bodies to eat snails.

-Spray molluscicides.

-Educate people on the importance of using toilets.


The drug niridazole kills one species of Schistosoma but may produce side effects.

Praziquantel seems to be effective against all species and has a few side effects.



  1. Malaria.

Malaria is one of the major killers in the tropics.

Cause:It is caused by a protozoa called plasmodium.

There are four species of the plasmodium that affect humans:

  1. Plasmodium malariae.
  2. Plasmodium falciparum.
  3. Plasmodium vivax.
  4. Plasmodium ovale.

Plasmodium lives in the blood stream of humans but unlike the trypanosomes, maralial parasites enter RBC and feed on their cytoplasm.


-Chills and high fever.

-Nausea and vomiting.

-Loss of appetite.

-General body weakness.

-Headache and joint pains.

Fever occurs every 48 to 72 hours according to which species has been injected.



-Malaria parasites destroy RBC, causing anemia.

-Fatality is possible in several attacks.


-Draining away unwanted ponds, pools and swamps.

-Where draining is difficult, kerosene and insecticides should be used.

-Vegetation should be trimmed.

-Sleep under mosquito nets use insecticides.

-Take preventive medicines regularly.

-Screen windows with mosquito proof were mesh.


Some forms can be treated with drugs such as Quinine, chloroquine or proguanil. New drugs such as Fansidar and Metakelfin have been established to kill malarial parasites.



  1. STI’s and typical STD’s.

STI’s are sexually transmitted diseases. They are caused by disease causing organisms. Virus, bacteria and fungi can cause them. STI’s causes STD’s such as gonnorhea, Syphilis, genital herpes and Chlamydia. These are also endemic diseases.

Secondary effects of most STD’s.

-Premature births, still births and abortions.

-Blindness of the foetus.

-Ectopic pregnancies.

-Sepsis causing death.

-Cervical cancers.

-Pelvic inflammation.

-Infertility and sterility.

-HIV infection.


Control and prevention.

-By not having sexual intercourse.

-By not sharing clothes.

-By maintaining cleanliness in toilet.



Groups of people likely to be infected by STD’s.

-Prostitutes who have intercourse for money.

-Other people who have had intercourse with other people.

-Casual acquaintances whose sexual activities are unknown.


Mostly young people are infected by STD’s.


  1. Gonnorhoea.

It is a contagious infection of the mucus membrane of the genital tract.

It is caused by a bacterium called Neisseria gonnorrhoeae or more often known as gonococcus. It affects the urethra in males and vaginal tract in females.



-A discharge of mucus and pus from urethra or vagina.

-Men experience pain and itching in urethra during urination.

-Women feel pain in lower abdomen.

-If not well treated, both sexes may become sterile.

-If it finds a way into the vas deferens, the testes swell and pain.



It is usually through sexual intercourse, and sometimes by birth.


Control and treatment:

It can be avoided by not having sexual intercourse.

It can be treated by kanamycin, streptomycin and penicillin.



  1. Syphilis

It is caused by an organism called Treponema pallidum. It is more dangerous than gonnorhoea.



-They may affect any part of the body.

-A hard swelling and ulcer may develop on sexual organs.

-If bacteria has invaded the body, it may cause skin rash and swollen lymph nodes.

-If not treated early, the spirochaetes form pockets of permanent infection in the body, causing inflammation, persistent ulcers and obstruction of the arteries.



-If bacteria invades heart or brain, they cause death.

-In pregnant women, Treponema bacteria can get across the placenta and infect the foetus. The infected foetus becomes mentally retarded and dies at an early age.



It can be transmitted mainly through sexual intercourse.

It can also be transmitted from mother to child through placenta.


Prevention and treatment:

-Avoiding irresponsible sexual behaviour.

-Antibiotics such as benzathine, penicillin and tetracycline are used to treat syphilis.



  1. Genital Herpes.

A virus called Herpes simplex causes it.



-Symptoms usually show up 21 days after exposure.

-Small painful blisters appear on sex organs.

-Blisters like drops of water on the skin burst and form open sores.

-The open sores dry up and become scabs.

-They can also result in the mouth as result of oral sex.

-Fever, nausea and genital pain often occur during the first episode.



It is spread through sexual intercourse.



Use condom.



It can be treated by Acyclovir.



  1. Clamydia/Clamidiya.

It is the most widespread STD today. It is very common in teenagers and young adults. It is caused by a bacterium called Clamydia trachomatis.




-Weight loss.

-Swollen glands.



-White spots on mouth.


Women’s symptoms:

-White and grey vaginal discharge.

-Lower abdominal pain.

-Bleeding between menstrual periods.

-Low grade fever occurs.


Men’s symptoms:

-Burning when urinating.

-Itching around penis.

-Pain and swelling in testicles.

-Low grade fever occurs.



-It can be transmitted through sexual intercourse.

-It can be avoided by not engaging in irresponsible sexual behaviour.



Antibiotics such as azithromycin, doxycycline and ofloxacin can treat it.





Kaposis sarcoma is a cancer of the skin and blood vessels, and of pneumonia caused by Pneumocytis carinii protozoa. It came to be known as Acquired Immune deficiency syndrome or AIDS.

What is HIV?

It is Human Immune deficiency virus. It is mainly found in body fluids such as semen, blood and vaginal secretions. Low amount have also been found in sweat, saliva and tears.

Signs and symptoms:

-Loss of weight.

-Fever and diarrhoea for more than one month.

-Severe cough for more than one month.

-Skin infections.

-Abnormal inflammation of lymph nodes.

-Abnormal mental condition signs.

Effects of HIV/AIDS.

-Infections e.g. TB, Skin cancer, pneumonia and diarrhoea.


Prevention and control:

-Through health and sex education.

-We can protect ourselves by avoiding unsafe sexual intercourse.


By following ABC rule:

  • Abstaining from sex.
  • Being faithful to one partner.
  • Use condom during sex.


-Avoid blood transfusion.

-Pregnant women with HIV/AIDS should go to clinic.


Care and support for people living with HIV/AIDS – (PLWHA.)

-Keep wounds covered.

-Do not share sharp things.

-Keep patients bed sheet clean.

-Keep patients clean by disposing his faeces, urine etc.

-Give patient extra fluid to drink.

-Don’t let the person smoke or use alcohol.

-Offer patient plenty of rest.

-Offer patient words of wisdom, hope and success.

-Never discriminate or stigmatize the patient.



Guidance means the process of helping an individual to gain self understanding and self direction.


Counseling is the process of helping a person to accept and use information or advice so he can solve his problem.


Aims of HIV/AIDS counseling.

-To reduce rate of HIV/AIDS transmission.

-To help those people already infected with the virus.


Stages of guidance and counseling.

  • Pre-test counseling.
  • Pro-test counseling.
  • Follow-up counseling.


Pre-test counseling.

It is a counseling that is given to the client before the blood is taken for testing to ascertain HIV/AIDS infection.


-Helping the client know what HIV/AIDS is.

-Means of transmission.

-Meaning of HIV test.

-Meaning of a positive or negative test result.

-Need for a confirmatory test.

-Need to practice safe sex.

-Need for informing sexual partners.


Post-test counseling.

-Available emotions.

-Spiritual and material support.

-Possible treatment program.

-Safe sexual practices.

-How to avoid infections.


Follow-up counseling.

Is a counseling given to a victim after confirming him to have positive results of HIV.










It is the system of sorting out and placing organisms into different groups on the basis of their similarities and differences.

Types of classification:

There are two types of classification:

  1. Artificial classification/system.
  2. Natural classification/system.


Artificial system.

In this system only one or a small number of features are considered e.g. birds and bats all have the ability to fly. So by using this system, one can place the birds and bats in one group. Just by considering one feature that is the ability to fly. But in reality, birds and bats are classified into different groups.

Birds -> Aves.

Bats -> Mammals.


Natural system.

In this system, organisms are placed in their natural groups by:

  1. Considering many features in common.
  2. Characters that show:

Homology- Similarity of origin.

Analogy- Similarity of use.

Example of Homology:

The arms of a man, forelimbs of whales and wings of birds or bats are homologous because they have same order and pattern of bones. So these show that they have the same origin.

Example of Analogy:

The wings of birds and grasshoppers are analogous, because birds have internal skeleton (endoskeleton) and grasshoppers have external skeleton (exoskeleton). So these wings perform the same function but have different origins.


Importance of classification:

  1. It helps us understand the characteristics of living things.
  2. It enables man to identify and name numerous organisms.
  3. It brings together living organisms with similar characteristics but separates those with different features.
  4. It helps man arrange information about living organisms in an orderly manner to avoid confusion.
  5. It makes the study of living organisms very easy.
  6. It provides an organized system into which newly identified similar organisms can be fitted in future.


Advantages of Artificial classification.

  1. Based on easy and simple characteristics.
  2. Uses convenient and readily observable characteristics.
  3. Based exclusively on arbitrary criteria.


Disadvantages of Artificial classification.

  1. Unrelated organisms may be placed in the same group.
  2. Tends to place closely related organisms into different groups instead of being grouped together.


Advantages of Natural classification.

  1. Avoids confusion

-Unrelated organisms can’t be placed in the same group.


  1. Accuracy.

-Closely related organisms with common characteristics features are placed in the same related group.


  1. Universal.

-Because it uses same system of naming organisms.


Disadvantages of Natural classification.

It is not based on easy and simple characteristics but on evolutionary relationships.


Is a scientific system of naming living organisms whereby each organism is assigned two names. The first name being the Genus and the second name is the species.

Note- Bi means two, Nomino means name.

So Binominal means two names.

Rules of binominal nomenclature:

  1. Only the first letter of the genetic name is capitalized and then the whole genetic name is underlined eg. Homo.
  2. The first letter of the species name is never capitalized, and then the whole species name is underlined eg. sapiens. So the scientific name for man is Homo – genus, sapiens – species.
  3. If the scientific name is written in italics, then it should never be underlined, but other rules remain the same.

Eg: Homo     sapiens    (Romanic)

Homo sapiens (Italic)


Examples of scientific names:


Man – Romanic:Homo  sapiens.

Italic:Homo sapiens.


Elephant – Romanic:Loxodorita   africane.

Italic:Loxodorita africane.


Maize – Romanic:Zea   mays.

Italic:Zea mays.


Dog – Romanic:Canis  familiasis.

Italic:Canis familiasis.


Leopard:Panthea pardus.

Italic:Panthea pardus.


Lion – Romanic:Panthea leo.

Italic:Panthea leo.


 Ranks of classification (Toxonomic.)

Ranks are the groups into which organisms are placed as the matter of convenience based on easily observable features, that are shared in common for group identification.


These are seven major ranks of classification, they are:

Animals. Plants.
Kingdom. Kingdom.
Phylum. Division.
Class. Class.
Order. Order.
Family. Family.
Genus. Genus.
Species. Species.


Genus:Is a group of organisms with a large number of similarities but unable to interbreed successfully.

Species:Is a group of organisms which are capable of interbreeding together and produce fertile offsprings.



There are five major kingdoms of living things. These major kingdoms exclude a virus. Because the virus is between living and non-living things. The major kingdoms are:

  1. Kingdom Monera.
  2. Kingdom Protoctista.
  3. Kingdom Fungi.
  4. Kingdom Plantae.
  5. Kingdom Animalia.



Is a chemical between living and non-living things.

Characteristics of a virus:

  1. They are living and non-living things.
  2. They are RNA or DNA.
  3. They can multiply only in living cells.
  4. Each virus is specific in its host and even of the type of a cell within its host.
  5. They are the smallest living or non-living organisms about 50 times bacteria.
  6. They can only be seen under electronic microsopes.


Image result for bacteriophage labelled

Economic importance of virus.

  1. They cause plant diseases.
  2. They cause animal diseases.
  3. They attack and kill bacteria.
  4. Used in making vaccines etc.


Kingdom Monera (Bacteria)

General characteristics.

  1. They are unicellular and very small organisms.
  2. They have cell wall made up of polysaccharides, cellulose, fat, proteins and chitin.
  3. They store food in form of glycogen, fats, proteins, sometimes sulphur.
  4. They are heterotrophic organisms.
  5. They are obligate bacteria’s- respires aerobically. Facultative bacteria- respire anaerobically, micro-aerophilous- respire in very low oxygen.
  6. They are capable of producing toxins which can poison other organisms.
  7. Bacteria can grow best in 30º-37ºc, 15º-20ºc, -2º – -9ºc, 60ºc and above.
  8. They reproduce by binary fission.
  9. They live in soil, dust, water, air, animals and plants. In addition to that, bacteria’s are enormous e.g. in 1cm3 of fresh milk, it contains more than 300,000,000 bacterias.
  10. Together with fungi, they cause decay of organic materials and hence recycling of nutrients.
  11. They are prokaryotic.

Forms of bacteria.

Coccus:It causes sore throat.

Diplacoccus:Causes pneumonia.

Streptococcus:Causes sore throat.

Staphylococcus:Causes boils.

Spirillium:Causes Syphilis.


Bacterium:Bacillus anthrax:Causes anthrax.

Economic importance of bacteria:

1. Production of antibiotics.

  1. Used in sewage (They decompose pollutants)
  2. Used in cheese and butter making.
  3. Used in vinegar and alcohol production.
  4. Used in fermentation process etc.


Kingdom Protoctista.

Members of these kingdom resembles the ancestors of plants, animals and fungi. These are the algae, protozoa etc. In protozoa we have amoeba and paramecium etc. other members of this kingdom are euglena and trypanosome. Algae contains red, brown and green algae.

General characteristics of Kingdom Protoctista:

  1. Are eukaryotic organisms.
  2. Many are unicellular.
  3. It includes organisms which resembles early plants (algae), early animals (protozoa) and early fungi (Oomycetes).
  4. Are the links between prokaryotes and modern eukaryotes.
  5. They locomote by the use of cilia or flagella.
  6. They have a contractile vacuole for excretion.
  7. They feed holophytically (This means that they feed autotrophically e.g. euglena and heterotrophically e.g. amoeba and paramecium.)
  8. They reproduce by binary fission and multiple division which means sexual and asexual.
  9. They contain a clear and visible nucleus.
  10. The locomotary structures are:

Amoeba- Pseudopolis.

Paramecium- Cilia.

Euglena- flagella.

Trypanosome- flagella.

Plasmodium- flagella.


Economic importance of Kingdom protoctista.

  1. Causes diseases e.g. sleeping sickness in man by a trypanosome transmitted by a vector called tsetse fly.
  2. Plasmodium causes malaria in man transmitted by female anopheles mosquito.

There are of 4 species:

Plasmodium vivax.

Plasmodium malariae.

Plasmodium ovale.

Plasmodium falciparum.


  1. The Entamoeba hystolytica causes amoebic dysentry.
  2. Entamoeba gingivalis causes periodontal disease. This is a dental disease transmitted by kissing.
  3. Growth medium that means the algae for caltering in lab.
  4. Used in ice-creams, paints and cosmetics are made from alginic acids.
  5. Algae are cultivated as human and fish food.


The function of the Golgi complex (apparatus) is to collect and pack all molecules synthesized within the cell.