bios

INTRODUCTION TO BIOLOGY

BIOLOGY

Biology is derived from two Greek words, that is, bios which means life and logos or logia which means study or knowledge.

So biology can be defined as a branch of science which deals with the study of life.

                                    OR

Biology is a study of living things or organism.

Living things include bacteria, fungi, animals, plants etc.

BIOLOGIST

A person specialized in the study of biology

LIFE

Life means being alive or existing. Something is alive or existing if it possesses life processes. The basic unit of life is cell. All living things are made up of cell, cell are so small that they cannot be seen with marked eye.

ORGANISM

Organism is anything which has life. It is the other name of a living thing. Organisms are made up of cells.

CELL

A cell is a basic unit of living things. The cell has three main parts, cell membrane, cytoplasm and nucleus. Cells which make up plants are called plant cells and those which make up animals are called animal cells.

BRANCHES OF BIOLOGY

Biology is a subject and it has many branches, but there are two main branches of biology

{1} Botany - is a branch of biology which deals with the study of plants. A person who studies botany is called a botanist 

{2} Zoology - is a branch of biology which deals with the study of animals. A person who studies zoology is called a Zoologist

However there are many minor branches of biology. That deal with different aspects of living things

OTHER BRANCHES OF BIOLOGY

a)      Entomology: refers to the study of insects

b)      Anatomy: Physical structure of organisms

c)      Cytology: Deals with cell

d)     Ecology: Relation between organisms and their Environment

e)      Mycology: Deals with fungi

f)       Taxonomy: How organisms are named and groups

g)      Physiology: How organisms body parts function

h)      Parasitology: Deals with parasites

i)        Immunology: The body defence against infections and disease

j)        Microbiology: Is devoted to the study of organisms that can be seen only with a microscope e.g. bacteria,

k)      Histology: Is the study of structure of tissues

IMPORTANCE OF STUDYING BIOLOGY

The following is an outlines of why the study of biology is important:

1)      It helps us to understand ourselves better since we are living things.

2)      It helps us to understand our environment better and principles of conserving

3)      It helps man to evaluate environment uses such as pollution, global warming and environmental degradations.

4)      Biology help to understand cause, symptoms, method of transmission, prevention, and treatment of diseases this improve the standard of living.

5)      It provides answer to fundamental questions.

6)      It helps us to enter in careers such as medicine, agriculture, reproductive, health and genetic Engineering.

7)      Biology helps us appreciate nature.

RELATIONSHIP BETWEEN BIOLOGICAL SCIENCES WITH OTHER RELATED FIELDS

Biology related to many other field of study such as forestry, agriculture, medicine, pharmacy, veterinary, medicine and nutrition.

1.      AGRICULTURE

Biology research finding on crops and livestock have led to improve agriculture production.

2.      MEDICINE

Medicine is the science and art of preserving health and treating illness.

3.      NUTRITION

Nutrition is the science which deals with food and how the body uses it.

4.      FORESTRY

Biologists have developed varieties of trees that grow well in dry areas, also that mature fast so as to prevent desertification.

5.      PHARMACY

Pharmacy is the profession concerned with the preparation, distribution and use of drugs.

CHARACTERISTICS OF LIVING THINGS

Living things have characteristics which make them different from non-living thing. These are;

1.      NUTRITION/FEEDING

       All living things take in food or make their own food. Living things need food to provide energy for activities such as growth, repair and health

2.      RESPIRATION

       Respiration is the breaking down of food materials within cells to release energy.

3.      EXCRETION

       Is the process by which excess wastes such as carbon dioxide, water, urea, ammonia material resulting from the chemical reaction occur in body cell are removed out of body.

4.      SENSITIVITY/ IRRITABILITY

      It is the ability of an organism to detect and respond to a change in its environment

Growth is an increase in size and mass of an organism that becomes more complicated and more efficient.

5.      MOVEMENT/ LOCOMOTION

      All living organisms are capable of movement. Movement is the change of position of the whole organism or just part of an organism. Plants just show movement in term of growth of their body parts. E.g. roots, shoots and leaves.

6.      Growth

Growth is defined as an irreversible (permanent) increase in size and dry weight of an organism involving differentiation. All living things need food in order to grow and build up their bodies.

7.      REPRODUCTION

      Reproduction is the process by which living things produce new individuals of their kind. This ensures that there is continued existence of the species and life forms.

        Non- Living things are referred to as inanimate Living things are referred to as animate

SCIENTIFIC PROCESS IN BIOLOGY

Biology, just like other science subjects, involves carrying out experiments. When studying living things simple observation can be made by using our own senses i.e. sight, smell, touch, taste and hearing. The senses can be detected by our sense organs i.e. eye for sight, nose for smell, skin for touch, tongue for taste and ear for hearing.

These organs are;

1)                The eyes for seeing

2)                The nose for smelling

3)                The ears for hearing

4)                The tongue for tasting

5)                The skin for feeling

Measurements: When carrying out biological investigation measurements like mass, time, temperature, and length are unavoidable

Instruments used for various measurements:

a.       Beam balance – for measuring mass

b.      Thermometer – for measuring temperature

c.       Clock/stopwatch – for measuring time

d.      Ruler – for measuring length

e.       Pulse rate can be measured by using a stethoscope or by pressing the fingers firmly on the skin.

In biological investigation like in any other scientific research, methods are listed. The scientific method is a set of steps that scientist use to study things.

Those methods are

a)      Problem identification

b)      Formulation of hypothesis

c)      Experimentation

d)     Observation and data collection

e)      Interpretation of data.

f)       Conclusion

Identification of a problem (problem statement)

In our day to day life we often come across questions or phenomena which require explanations. Such questions or phenomena are of interest to a biologist who will seek to provide answers to them.

The phenomena could be for example; it was observed that the harvest of tomatoes in Juma’s garden was low despite frequent irrigation, correct planting techniques, timely planting and adequate sunlight. So, what was the problem with Juma’s garden?

Hypothesis formulation

Hypothesis is a tentative explanation for the observation made. Using your example of low yield in the tomato garden, the possible hypothesis could be poor yield could have been caused by low soil fertility and therefore application of the fertilizer could increase harvest of the tomatoes in the garden. This hypothesis must therefore be tested by experimentation if it has to be a scientifically acceptable explanation.

Experimentation

An experiment is a series of investigation intended to discover relationship or certain facts that may lead to finding a problem. In the case of low harvest of tomatoes, you are first supposed to construct a plan of investigation as follows:

Select two plots, A and B, from the same garden and subject both of them to the same conditions as before. In plot B apply fertilizers while in plot A don’t put any fertilizers (plot A will be your control plot).

Observation and data collection

After setting up an experiment, a researcher must observe and record data. Observation is done by using sense organs such as ears, eyes, nose and skin. The researcher must record whatever he observes. The researcher obtained X kg in plot A and Y kg in plot B.

Interpretation of data

Once a researcher has collected data, he should try to explain the meaning of data in relation to the purpose of the experiment. In the tomato garden experiment, the harvest in plot A was little compared to the harvest in plot B.

In these plots, all the conditions were the same except that in plot A no fertilizers were applied while in plot B fertilizers were applied. Therefore, high harvest in plot B was a result of applying fertilizers. If this experimentation is correct, then the same results should be obtained if the experiment is repeated under the same conditions

Conclusion

At the end of investigation, a researcher must draw conclusion. This conclusion is based on the collected data. The conclusion is either confirmation or rejection of the hypothesis under investigation.

In the tomato garden experiment, the results have shown that application of fertilizers has increased the harvest of tomatoes. Therefore, low harvest of tomatoes was caused by poor soil fertility.

Summary

The following diagram summarizes the scientific process.

The scientific process

BIOLOGY LABORATORY

A biology laboratory is a room or building specially designed for carrying out biological experiments.

The biology laboratory rules

Biology laboratory has sophisticated instruments which need to be handled with special care. Chemicals which are being used are potentially harmful and they need a special attention when working with them.

The following laboratory rules should be adhered to:

1)      Don’t enter in the laboratory without permission from the teacher or laboratory technician.

2)      Do not play, or run unnecessarily in the laboratory.

3)      Do not eat or drink in the laboratory.

4)      Do not use chemicals or handle apparatus or specimens without instruction from the teacher or laboratory technician.

5)      Any accident or damage of apparatus must be reported.

6)      Label chemicals and specimens to avoid confusion.

7)      Always keep flammable substances away from flames.

8)      Turn off water and gas taps after use.

9)      Never point the open end of the test tube to your fellow or yourself when heating.

10)  Never smell substances, specimens, chemicals or gases directly.

11)  Wash your hands with soap after the experiment.

12)  Clean the apparatus and benches after the experiment.

13)  Return the apparatus and chemicals to their normal position after use

Distinguishing the biology laboratory from other facilities

The biology laboratory is different from other school facilities such as classroom, library or physics and chemistry laboratory.

ü  A class room has desk and chairs, students are taught in a class room.

ü  A library has variety of reading materials some libraries have tables and chairs where we can sit and read.

ü  A biology laboratory has models, specimens, cage, aquaria and chart which may not be in physics or chemistry laboratory.

ü  Some of unique things found in biological laboratory are preserved specimens of organisms such as insect, micro-organism and plants.

WARNING SIGNS/ SAFETY SYMBOLS

Some of the chemicals and apparatus used in biology laboratory may be harmful or dangerous. Before starting using any chemical you must know whether the chemical is toxic, flammable, oxidizing, explosive or irritant/harmful. To help you recognize such dangerous substances, the containers of modern chemicals carry special chemical warning signs as indicated below.

Toxic

Toxic substances can cause death. They may be poisonous when swallowed, breathed in or absorbed through the skin. Examples of toxic substances include acids and alkalis, lead II acetate and potassium dichromate.

The symbol for toxic substances is represented as shown above.

Flammable

Flammable substances are substances which can catch fire easily. Examples of such substances include petrol, alcohol, Thomas Baker (Phosphorus yellow or phosphorus red) and potassium metal. These substances normally evaporate fast and therefore should not be brought near open flames. The symbol is as indicated above.

Corrosive

Corrosive substances attack and destroy living tissues. They may destroy the floor, desks as well as metals, examples of corrosive substances are concentrated acids, e.g. sulphuric acid, hydrochloric acid, nitric acid and concentrated alkalis e.g. sodium, potassium and ammonium hydroxides. If by accident a corrosive substance comes into contact with your skin, go to the sink and wash with a lot of water. The symbol is shown above.

Oxidant

An oxidant is a chemical or substance which accelerates burning. Small fires can be made big in the presence of oxidizing agent. Examples of oxidizing agents include potassium permanganate, potassium chlorate, and zinc nitrate.

Explosive

An explosion is a forceful rapid reaction which involves random throwing of particles

Harmful or irritant

Harmful substances have a long term effect. They do not kill immediately. They have a cumulative effect. Therefore careful handling is required.

Irritant substances cause pains on the skin or eyes. They can endanger one's health if they come into contact with the skin or eyes for too long. Examples of harmful substances include lead chloride, lead nitrate, lime water ferrous sulphate and manganese (IV) oxide

BIOLOGY APPARATUS

Biology apparatus are the tools and equipment needed in order to study Biological experiments effectively. Some apparatus and equipment used in the biology laboratory

1)      Hand lens: Used to magnify specimen/object.

2)      Sweep nets: Used to catch small flying organisms. E.g. Butter flies, housefly

3)      Fishing nets: For catching fish and aquatic animals

4)      Petri-dish: Is a shallow glass where specimen are put for close observation

5)      Mortar and pestle: Is small hard bowl used for crashing or grinding substances

6)      Crucible: Is a container in which substances are heated to very high temperature

7)      Thermometer: Used to measure temperature

8)      Dissecting Kit: Is a kit that contain all tools for making dissection of specimen

9)      Spirit - burner Bunsen – burner: Used as a source of heat

10)  Dropper: Used to add liquid during experiment

11)  Spatula       : Used for taking some substance from the container

12)  Test tube holder: Used to hold test tube

13)  Test tube: Used to hold and heat chemicals

14)  Test tube rack: Storing test tube

15)  White tiles: Used to put specimen during experiment that involve colour changes

16)  Watch glass: Is a shallow dish that used as evaporating surface or cover for beaker

                                         THE MICROSCOPE

  

A microscope is an instrument used for viewing objects which are too small to be seen by our naked eyes.

               THERE ARE TWO TYPES OF MICROSCOPE

1)      Compound or Light microscope: Light microscope can magnify object up to 2000 times. This is the type of microscope that is commonly used in school laboratory.

2)      Electron microscope: Electron microscope can magnify a specimen up to 50000 times.

PARTS OF A LIGHT MICROSCOPE AND THEIR FUNCTION

Parts of the light microscope has the following functions:

1.       Eyepiece – Magnify objects under observation since it consists of magnifying lenses.

2.       Body tube – Hollow tube attached to the arm. Its function is to hold eyepiece lens and revolving nose piece.

3.       Revolving nose piece – Holds objective lenses in place. Position of the objective lenses can be changed by manipulating the revolving nose piece.

4.       Coarse adjustment knob – It lowers and raises the body tube so that a clear image is obtained.

5.       Fine adjustment knob – Raises and lowers the body tube to obtain a fine focus.

6.       Objective lens – Brings image into focus and magnifies it.

7.       Stage – This is a place where specimen to be observed is placed

8.       Clips – Hold the slide or specimen in position

9.       Mirror – Reflects and directs light to the object under observation.

10.   Diaphragm – Is an aperture that regulates the amount of light passing through the condenser to illuminate the specimen

11.   Condenser – Concentrates light reflected by the mirror.

12.   Base or stand – Supports the microscope steadily

13.   Arm or limb – Supports the body tube and stage. It is used to hold the microscope

14.   Hinge screw – Raises and lowers the stage.

THE STRUCTURE OF THE LIGHT MICROSCOPE

How to use light Microscope

a)      Place the microscopes on the laboratory bench or table make sure it's not near the edge.

b)      Mount the specimen on a microscope slide, cover it with the cover slip.

c)      Make sure that the low power objective lens is on line with the eyepiece lens.

d)     Place the slide with the specimen on the stage.

e)      While looking through the eyepiece, use your hand to adjust the stage so the light is directed at the specimen on the stage.

f)       Adjust the course adjustment knob to bring the specimen focus.

g)      Adjust the fine adjustment knob to bring the specimen into sharp focus.

h)      Rotate the nose piece to a lighter power objective lens if you want to observe more details on the specimen.

How to care for light Microscope

1)      Use both hands to carry the microscope. One hand should hold the base and the other hand should hold the arm.

2)      Always place the microscope on the desk or table carefully and gently and never place it at the edge of the bench.

3)      Keep the microscope in an upright position when using liquids or when not in use.

4)      Keep the stage clean and dry. If any liquids are spilled on the microscope, wipe them up immediately with a piece of tissue.

5)      Focus with the low-power objective lens first.

6)      Focus by moving the lens away from the slide, that is, by increasing the working distance.

7)      Consult your teacher if the lenses are dirty.

8)      Consult your teacher if the adjustments do not work freely.

9)      When your work is completed, move the low power objective lens into place and remove your slide.

10)  Keep your microscope covered when it is not in use and keep your work area clean and tidy.

SAFETY IN OUR ENVIRONMENT

FIRST AID AND SAFETY

First Aid is an immediate help which is given to a sick or injured person before sending him/her to the hospital for further treatment.

IMPORTANCE OF FIRST AID

ü  Saves life

ü  Reduces fear of death

ü  Brings hope and encouragement to the patient

ü  Relieves the victim’s pain

ü  Prevents the illness or injury from becoming worse

ü  Helps a person to recover from shock

ü  It shows spirit of helping each other.

THE FIRST AID KIT

First Aid kit is a small box which is used to keep instruments and chemicals for First Aid. The first Aid kit should be placed in a safe and accessible place.

Components of the First Aid kit and Their Uses

1)       Plaster or adhesive bandage: Covering small wounds

2)       Sterile gauze: Covering wounds to protect them from dirty and germs

3)       Antiseptic: Cleaning wounds to kill germs

4)       Soap: Washing hands/ wounds and equipment

5)       Pain killers: Relieving pain

6)       Scissor and razor blade: Cutting dressing materials

7)       Safety pins: Securing bandage

8)       Bandages: Keeping dressing in place and immobilizing injured limbs

9)       Cotton wool: Cleaning and drying wounds

10)   Thermometer: Taking body temperature

11)   Disposable sterile gloves: Preventing direct contact with victim's body fluids

12)   Petroleum jelly: Smoothing chapped skin

13)   Torch: As a source of light

14)   Whistle: Blown to call for help

15)   Spirits: To kill germs in wound

        Procedures of Giving First Aid to Various Victims

          SNAKE BITES

A poisonous snake has two fangs one on each side of the upper jaw. The fangs are as sharp as needles. At the root of the fang there is a poison gland. When the snake strikes, it jabs downwards hitting the skin with its fangs and releases a few drops of venom.

Venom is the poison of the snake, the action of striking forces the poison out and injects into the victim’s skin.

Sign and symptoms

ü  Immediate pain and swelling after the bite

ü  The skin becomes purple One or two punctured points may be seen where the fangs passed through the skin

SCORPION BITE

Scorpions are armed with a single curved stinger in the tail. Through this, they inject powerful venom that may produce convulsions and temporary paralysis.

The affected area feels as though it had been burned with a hot spark

How to give first Aid to a victim of scorpion bite

1)       Apply tourniquet

2)       Put ice on the injured area to relieve pain and prevent spread of the poison

3)       Treat for shock

4)       Rush the person to the hospital

DOG BITE

When someone is bitten by a dog, keep the dog under observation to see whether it has rabies. Rabies is one of the worst diseases known. It is caused by a virus which is present in the saliva of the infected animal.

If the animal has rabies, it will become restless, excitable, refuse to eat and barking tone will change. Later the dog then starts barking excessively.

How to help a victim of dog bite

ü  Wash your hands well with soap and water

ü  Wash the wound thoroughly with soap and water to remove the animal’s saliva using running water.

ü  Cover the wound with clean gauze.

ü  Bandage it carefully

ü  Take the victim to the hospital.

INSECT BITES

1. Spider bites: Some spiders have a harmless venom to man. But the black spiders can be dangerous to man. The injured person becomes weak and dizzy, feels nauseated and the muscles of the stomach may become hard especially in children.
2. Black and fire ants, bees: When a person has been stung by e.g. bees, severe pains are felt immediately. The person may be shocked, itching and swelling may follow.

A victim of spider bite can be helped by sending him/her to the hospital.

How to help

ü  Remove the insect’s sting

ü  Apply household ammonia and ice cubes

ü  Treat for shock

CHOCKING

Choking is caused when food or a foreign object becomes lodged in the windpipe.

Have you ever been with a person who is chocking? Did you know what to do?

When you are with a person that is chocking, first notice if person can talk, breath or cough. If so stay with that person until the air way is cleared by coughing.

Caution: Do not try to slap the person on the back. The slapping may cause the food to become more deeply ledged in the wind pipe.

If a person cannot talk or cough and appears to have a difficult in breathing, apply quick abdominal thrusts i.e. Heimlichmaneuver as follows;

ü  First stand behind the chocking victim

ü  Put your arms around the person, placing your firsts just below the breast bone as shown above.

ü  Give a series of quick, sharp upward and inward thrusts

These thrusts push in on the diaphragm and the thoracic cavity suddenly decreasing its volume.

Air pressure is exerted below the obstruction which projects it forcefully from the windpipe.

POISONING

A poison is any substance which can loss of one’s life or seriously endanger health when taken into the body.

In every household there are different kinds of things which are poisonous. Some are deadly even on a very small dose. Others may be more or less harmless when taken in small quantities.

If the poison has been swallowed, give a glass of milk or water or both. This helps to dilute and neutralize the poison, don't introduce vomiting if the poison is a corrosive. Introduce vomiting if the poison is none corrosive substances. Vomiting can be induced by putting your finger in the victim's throat or by making the victims gargle soap water or raw egg yolk, take the person to hospital immediately.

BONE FRACTURE

A person with a bone fracture experience the following;

ü  Severe pain around the injured part

ü  Lack of movement

ü  Swelling

ü  Fainting or shock

How to help

ü  Treat for a shock

ü  Keep the patient absolutely quite

ü  Prevent further damage to injured part by using a splint.

BONE DISLOCATIONS

These are bones which have come out of place at a joint.

How to help

ü  Bring the bone back into fixed position

ü  Bandage it firmly in place so that it does not slip out again

SHOCK

Shock is a sudden violent disturbance of the mind or emotion

Causes of shock

a)      Bad news

b)      Severe illness

c)      Heavy bleeding

d)     Dehydration

e)      Severe burns

f)       Accident

Ways of preventing shock

ü  Lie down the person with his feet higher than his head

ü  Loosen the belt and shoes

ü  If the person is conscious give him some tea or any soft drink.

ü  Treat his/her wounds if any

ü  Stop any bleeding Keep the person warm if he/she feels cold

ELECTRIC SHOCK

How to help

ü  Switch off the electricity immediately

ü  If not possible to switch off the electricity, take the victim away from the source of electricity using a dry wooden material or rope.

ü  Loosen any tight clothes

ü  If the person is unconscious, apply mouth to mouth respiration

ü  Treat for shock

ü  Take the person to the hospital immediately

BRUISES

A bruise is an injury beneath the skin. Bruises can be identified by pain, swelling or a mark under the skin.

How to treat bruises

ü  Wash your hands using water and soap

ü  Wash the bruised part

ü  Apply cold clothes or ice immediately to reduce pain and swelling

ü  If swelling continues take the victim to the hospital

VOMITING

Vomiting is an involuntary ejection of substance from the stomach through the mouth.

Possible causes of vomiting

a)      Allergic reactions

b)      Diseases e.g. malaria

c)      Physiological condition e.g. pregnancy

d)     Food poisoning

e)      Unpleasant smell or taste

f)       Drinking a lot of water when thirsty.

How to help

ü  Give the person a rehydration drink or oral rehydration salts solution.

ü  Allow the person to have a complete rest

ü  If vomiting continues, take the patient to the hospital.

MUSCLE CRAMPS

Muscle cramps occur as a result of uncontrolled muscle spasms and contraction.

How to help

ü  Lay the victim down

ü  Massage the cramped area gently

ü  Apply some anti-cramp ointment to the affected area

ü  If the problem persists seek for a medical help

Muscle cramp can cause;

ü  Severe pain

ü  Loss of movement

DROWNING

Drowning is a situation where someone has stopped breathing due excessive drinking of water following sinking into water.

Offering first aid to a drowned victim

ü  Lay the person on his back and tilt his head backwards so that his mouth falls forward

ü  Pull the tongue forward. Use a dry cloth to hold the tongue.

ü  Hold his nose close with your fingers

ü  Carry out mouth to mouth breathing by blowing gently into the person’s mouth about 30 times a minute but do not blow too hard. This process is called artificial respiration.

ü  Keep the person warm.

FAINTING

Fainting is caused by a temporary fall in the blood supply to the brain, sometimes brought on by emotional shock or prolonged standing.

How to help

ü  Keep the victim lying down with his/her legs raised in order to maintain blood pressure in the brain

ü  Do not try to warm the victim.

ü  Loosen any tight clothing around the neck, chest and waist.

ü  Supply the patient with plenty of fresh air by fanning or mouth to mouth respiration.

ü  If there is no improvement rush the victim to the hospital

BLEEDING

How to help the victim

(a) Severe cuts

ü  Severe bleeding with blood flowing out rapidly must be stopped at once by pressing with fingers directly on the wound or pressing the edges of the wound together.

ü  Lay the victim down.

ü  If the wound is in a limb raise it provided it is not fractured.

ü  When the bleeding has slowed down press a pad of material over the wound and tie it rapidly in place.

ü  If blood oozes through, apply more material on top of the original pad.

(b) Simple cuts

ü  Wash your hands well by using soap and water

ü  Wash the wound

ü  Cover the wound with clean dressing dipped in iodine solution and bandage the wound

(c) Nose bleeding

 Bleeding usually occurs near the tip of the nose. The bleeding may be a result of diseases such as

ü  High blood pressure

ü  Rheumatic fever

ü  Injury

ü  Nose bleeding is also likely to occur at high altitude as a result of cold.

How to help

ü  Let the victim sit quiet. This makes the heart beat to slow down and hence reduces bleeding.

ü  Let the victim lean the head slightly backward or make him/ her lie down on his/ her back.

ü  Press on the side of the nose where the blood is flowing for about 10 minutes.

ü  Allow the victim to breathe through the mouth

ü  Apply cold, wet compression over the nose and face. If this does not work take the victim to the hospital

BURNS AND SCALDS

A burn is caused by dry heat e.g. flame of hot object. A scald is caused by a steam or boiling water. The treatment is the same for both burns and scalds except that in scalds any wet clothing should be carefully removed while in burns clothing should be left in place. If clothes are burning cover the victim with a heavy blanket to cut off the air supply.

Dip the burning limb into clean cold water or press the affected area gently with an ice block. Do not break the blisters. Cover the injured area with clean dry cloth to keep away bacteria entering the damaged tissue. If the situation is serious take the victim to the hospital immediately.

CHEMICAL BURNS (ACIDS AND ALKALIS)

How to help

ü  Strip off all clothing which has been contaminated by the chemical.

ü  Wash the affected area with plenty of water.

ü  Apply moist packs soaked in a weak solution of baking soda.

ü  Vinegar can be used for alkaline burns.

HICCUPS

Hiccups is due to involuntary contraction of the respiratory muscle, giving a characteristic sound

How to help

ü  Pulling out the tongue

ü  The victim may swallow finely crushed ice

ü  Holding a breath for a long time may also help

ü  Children can be given a teaspoonful of a weak solution of sodium bicarbonate or lemon juice.

SAFETY AT HOME AND SCHOOL

An accident is something unexpected that may cause injury and sometimes lead to death. Accidents may be difficult to predict and prevent.

Below is a list of some common accidents at home and school:

ü  Bites e.g. snake bite, insect bite, scorpion bite and dog bite.

ü  Burns caused by hot liquids, cooking pot, lamps, hot food, steam, burning wood, charcoals and those caused by corrosive chemicals such as concentrated acids and strong alkalis.

ü  Falls, e.g. wall falls, tree falls, bed falling, etc.

ü  Cuts and scratches caused by knives, hoes, razor blades and other sharp objects.

ü  Choking caused by drinks, food or objects

ü  Electric shock due to unguarded electric outlets and lightning.

ü  Poisoning caused by taking chemicals and excessive intake of medicines.

ü  Foreign bodies in the eye, ear and nose

ü  Drowning which may occur in very small amount of water such as baths, ponds, pit latrines, wells and water tanks.

ü  Nose bleeding, bruises, suffocation, fainting etc.

WASTE DISPOSAL

Waste: Refers to materials which are not needed.

Waste disposal: is way in which get rid of waste materials

TYPES OF WASTE

According to physical state, wastes can be classified as;

a)                 Solid waste

b)                Liquid waste

c)                 Gaseous waste

d)                Sludge waste

Solid wastes

These are wastes which comprise of about 73% of the solid wastes. Example of solid wastes include house hold solid wastes such as vegetable, fruit and garden wastes, papers, cans, plastics, bread wrappers, broken glassware, batteries from watches, radios, mobile phones, etc. and junked automobiles.

Industrial solid wastes

These types of wastes include packaging materials, metal turnings, scrappers, plastics and junked automobiles.

Medical solid wastes

These include packaging, used syringes and soiled dressings.

Market, yard and street sweepings

These are wastes such as paper, glass, cans, plastics, and vegetable wastes.

Liquid waste

Liquid waste include urine, water from bathrooms, water from kitchen after washing utensils, liquid also come from industries e.g. chemical liquid waste.

Gaseous waste

This is waste in gaseous form for example ammonia, carbon dioxide and sulphur dioxide gases from materials and lead from petrol in motor vehicle. Gaseous waste is a major risk factor for both acute and chronic respiratory diseases

Most of the gaseous wastes come from industries and automobile exhaust fumes, laboratories and burning of organic materials such as plastics and polythene bags

Sludge wastes

These are semi-solid wastes i.e. wastes which are neither solids nor liquids, for example, a mixture of livestock urine and cow dung

Waste disposal

Waste disposal is the process of getting rid of waste materials that people generate or the act of getting rid of unwanted materials and items of no value or in excess. This helps to reduce adverse effects of waste on human health, animal's health and environment.

Basic principle of waste disposal

The principles that can help us to better manage waste, these are:

Basic principle of waste disposal

The principles that can help us to better manage waste, these are:

a)      Reducing amount of waste we produce, for example we do not have to buy plastic bags each time we go shop we can carry a woven basket instead.

b)      Re- using items instead of throwing them away for instance we can use an empty margarine container to store sugar.

c)      Recycling waste materials - some waste can be changed to other product for example, broken glass can be melt and use to make new glass bottles

Importance of waste disposal

ü    It helps to provide attractive environment.

ü    It removes or reduces bad air.

ü    It reduces the spread of infections and disease.

ü    To prevent accident

Methods of waste disposal

a)      Burning

Waste such as papers, plastic, carton - boxes, empty milk packet, bread wrappers, are burnt to ashes.

b)     Burying

This is used to dispose inorganic waste such as empty containers of insecticides, used torch batteries, damaged bottles, pots, plates, cups and spoon.

Burying can take the following form - Pit latrine

The sewage in pit is rotten by bacteria, when the pit is full it's covered with soil and a new latrine is dug.

-Tipping and landfills

When car or truck come and gather waste and take it to dumping site we called it tipping

Damping can be in form of a dump or landfill.

A landfill is place where solid waste buried in the ground.

c)      Animals feeds

Organic waste such as vegetable, fruit, potato and banana peelings, cabbage, and spinach leaves are feed to goats, sheep, cattle, poultry and also pigs. Bones are dried and ground into powder which is dog food.

d)     Compost manure

After splitting inorganic refuse from organic. A place of one meter deep is dug where the organic refuse is dumped to decay, to keep away flies reduce smell and other health hazards, a thin layer of wood ashes and sock is used to cover the waste. After the refuse decomposes, it's used by agriculturalist as compost manure which adds soil fertile.

e)      Recycling

To recycle is to turn waste materials into valuable ones that can be used again. Plastic, glass, paper, metal and rubber are the items that can be recycled for example paper can be transformed to tissue paper or news print paper, worn out tires can be retreated and re- used, plastic items old glass bottles can be crushed and made into new bottles.

f)       Incinerating

To incinerate is to burn something until it is totally demolished. This process is carried out in an incinerator. Incinerator is usually done for hazardous material such as clinical waste.

g)      Garbage collection

Garbage collection in urban areas is done by local authorities, local authorities provide waste bins which are commonly placed at strategic places in towns. Garbage disposal are through landfill and incineration

THE EFFECTS OF POOR WASTE DISPOSAL

The following are some of the effects of poor waste disposal;

ü  Poor waste disposal causes air pollution result to respiratory diseases.

ü  Ruin the areas appearance

ü  Decomposing wastes produce flammable gas called methane and this may result to explosion of the gas which may cause a loss of material property and human life.

ü  Rain water drains through refuse and carry harmful substances to nearby streams and water used for drinking which may later lead to eruption of diseases like cholera and may kill organisms found in water

ü  Poor disposal of clinical wastes on land fill site may encourage bacterial breeding leading to possible infections in the area

ü  Unregulated dumps where waste is burned in the open can cause smoke and foul smelling air.

ü  Burning may also result into production of air pollutants which may affect the ozone layer and possible cause of respiratory diseases.

HOW TO REDUCE WASTE PRODUCT

ü  Use duster or cloth instead of paper to wipe surface e.g. window and furniture. It’s much cheaper in the long run and decreases the amount of waste paper in the environment.

ü  Invest in a set of cloth or woven shopping bags.

ü  Purchase rechargeable batteries and a battery charger instead of disposable batteries.

ü  Collect and use plastic container to store food.

ü  Initiate consciousness campaigns in your community on the proper ways of disposing waste.

ü  Use plastic that can be recycled or re - used and buy products made from recycled materials

                                                  

                                         

                                                       Symbol of recycled material

                                  Why waste product is a problem

ü  People's negative behavior patterns for instance dumping waste on pathways, on the roadside and using excessive packaging for example wrapping a piece of candy to layers of plastic.

ü  Inadequate disposal facilities make waste removal a problem.

ü  Failure by the local authorities to apply effective punishment on those who failed to practice proper waste disposal.

ü  Poor infrastructure/ poor settlement planning render waste collection.

                                          Why increase of waste production now today?

ü  Increase of population and new settlement.

ü  Increased consumption rate of more disposable packaging and foot waste.

ü  Technical advancement cause nuclear waste.

              HEALTH AND IMMUNITY

Health-Is a state of physical, mental and social wellbeing. It involves more than just the absence of disease. A truly health person not only feels good physically but also has a realistic outlook on life and gets along well with other people.

Immunity - Is the capacity of the body to oppose infections and sickness. Immunity builds the body's defense against infectious diseases. Through this, it helps us to stay healthy.

TYPES OF IMMUNITY

Basically there are two types of immunity namely:

a)      Natural immunity

b)      Artificial immunity

Natural immunity

Natural immunity is that which an individual is born with. Natural immunity can be divided into categories, namely

ü  Natural active immunity: This immunity develops in a body after a natural infection. After infection, antibodies are produced in the body. The antibodies normally reside in the blood or in other parts of the body. The body can make more antibodies whenever the pathogen tries to attack the body again.

ü  Natural passive immunity: This type of immunity is achieved during development of the foetus where antibodies pass from the mother to the foetus through placenta or through the mother’s milk after the baby is born. The antibodies disappear from the infant a few months after birth.

Artificial immunity

Artificial immunity is that which an individual acquires during his/her life time.

Artificial active immunity

This is immunity introduced in the body by immunization. Immunization is the process of introducing a vaccine into the body of an animal in order to increase its ability to produce antibodies. These antibodies protect the person if he/she is exposed to the actual disease.

ü  Most vaccines contain disease-causing bacteria or viruses that have been killed.

ü  Others consist of the live germs but in a weakened form or attenuated.

ü  Toxoid vaccines are made from poisons produced by disease-causing organisms.

ü  These poisons are chemically treated so that they provide immunity without causing disease.

ü  Some vaccines are made from parts of disease-causing organisms.

Vaccines have been developed against many diseases such as chicken pox, diphtheria, influenza, measles, meningitis, mumps, pneumonia, poliomyelitis, cholera, rabies, rubella (German measles), tetanus, whooping cough and yellow fever. Vaccines can be taken through, injection, rubbing or the mouth (orally).

Artificial passive immunity

This type of immunity involves the injection of serum into the body of an organism. Serum contains antibodies that have been formed in another person or animal. It provides immediate protection from infection and lasts for weeks or months and after that period there are no antibodies left in the body and therefore no immunity.

Factors which may lead to low of body immunity

1. Alcohol and other toxic drugs.
2. Lack of immunisation.
3. Lack of proper balanced diet.
4. Inability of the body to produce antibodies and white blood cells.
5. Pathogens of HIV (Human Immunodeficiency Virus
6. Incomplete treatment
7. Genetic disorders
8. Extreme stress

i.         Damage to the skin.

PERSONAL HYGIENE AND GOOD MANNER

Personal hygiene refers to individual cleanliness. It mirrors on how one takes care of oneself.

Good manners refer to acceptable person’s ways of behaving towards others.

PRINCIPLES OF PERSONAL HYGIENE

ü  Eating balanced diet regularly to maintain good health

ü  The body should be washed daily and hair combed regularly

ü  Teeth should be brushed after every meal

ü  The nails should be cut short

ü  Wear clean and ironed clothes

ü  Avoid risk behaviours like smoking cigarettes, drinking alcohol, prostitution and others

ü  Wash your hands with soap before and after meals and after visiting a lavatory

ü  Have enough sleep and rest.

ü  Take regular exercises to maintain fitness

ü  Underwear should be changed regularly

ü  Bedding should be changed regularly

REQUIREMENTS OF PERSONAL HYGIENE AND GOOD MANNERS

a)      Requirements of personal hygiene and good manners include towel, soap, comb, brush, basin, toothbrush, a pair of scissors, razor blades, water and cosmetics.

b)      Listen to advice from people who have good personal hygiene and good manners and learn from them, good advice help us to improve ourselves.

IMPORTANCE OF PERSONAL HYGIENE AND GOOD MANNER

a)      Reduces chances of pathogen infection

b)     Enhances social acceptance in the society

c)      Prevents one from getting choked while eating

d)     Maintains natural body state

e)      Maintains personality of an individual in the society

f)       One becomes respected by others

g)      Maintains health of the body and mind

MAINTAINING PROPER PERSONAL HYGIENE DURING PUBERTY STAGE

Puberty is the adolescent period. It is the period when one experiences physiological changes in the body. The physiological changes mark the beginning of adolescence. Puberty begins the age of 10 to 12 years for girls and 11 to 14 years for boys.

Ways of maintaining proper hygiene during puberty

a)      Both sexes should wash their bodies regularly

b)      During menstruation, girls should use good quality sanitary towels or pads and change them as necessary.

c)      Boys should undergo circumcision and females should avoid female genital mutilation

d)     Underwear should be washed and changed regularly

e)      Both boys and girls should avoid irresponsible sexual behaviours such as prostitution and rape so as to keep away from sexually transmitted diseases (STDs)

f)       Hair in the armpits or pubic areas should be shaved or trimmed

CHANGES IN GIRLS AT PUBERTY STAGE

ü    Body size increase rapidly

ü    Breasts develops

ü    Hair grows in the armpits and pubic area

ü    Waist narrows and hips broaden.

ü    Menstruation begins

ü    Pimples may develop on the face

ü    Sweat and oil glands become more active leading change in body

ü    High pitched voice

CHANGES IN BOYS AT PUBERTY STAGE

ü    Body size increase rapidly

ü    Reproductive organs enlarge

ü    Muscles grow

ü    Hair grows on the face (beards) and in the armpits and pubic areas

ü    Shoulder and chest broaden and voice deepens

ü    Wet dreams begin and sperm production begins

ü    Pimples may grow/develop on the face

ü    Sweat and oil glands become more active leading to change the body odour

-So it’s very important to maintain personal hygiene so as to prevent oduor and disease during puberty

Also aim at being well behaved all the time by taking the following measures

ü  Resist negative peer pressure

ü  Get counselling from a reliable person

ü  Apologize if you hurt other people's feelings

ü  Do not engage in sexual activities before marriage.

ü  Strive to be respectful to your elders even when you disagree with them.

ü  Get involved in positive extracurricular activities e.g. sports, debating and drama.

           Avoid engage on:

ü  Taking drug (drug abuse)

ü  Sexual affair

ü  Being rude to elders

INFECTION AND DISEASE

Infection is the invasion of disease-causing micro-organisms into the body. Disease is the disturbance of the normal state of the body. It is a disordered state of an organ or organism. Infections normally lead to diseases.

Classification of diseases

Diseases are classified as:

1.      Infectious (communicable) diseases

2.      Non-infectious (non-communicable) diseases

Infectious (communicable) diseases

These are diseases which can be transmitted from one person to another person. Communicable diseases are normally caused by micro- organisms like viruses, bacteria, fungi and protozoa, etc.

Examples of infectious diseases include: malaria, typhoid, tuberculosis, cholera, gonorrhoea, syphilis, Ebola, AIDS, chlamydia, etc.

Many of the infectious diseases are transmitted by a way of:

ü  Droplet of liquid

ü  Air

ü  Food or water

ü  Sexual intercourse

ü  Touch or contact e.g. ringworm

ü  An intermediate organism called a vector e.g. malaria by mosquito and bubonic plague by rat flea.

Diseases causing micro-organisms can enter the body through mouth, nose, skin, vagina, anus, penis, ears, eyes and open wounds.

Infectious diseases can be:

a.       Epidemic disease - a disease that affects a larger number of people in a short period of time in a region for example, cholera, meningitis, bubonic plague, rift valley fever (RVF), tuberculosis, etc.

b.      Pandemic disease - a communicable disease which is wide spread over a country continent or the whole world, for example HIV/AIDS, etc.

c.       Endemic disease - a communicable disease which occurs in an area continuously for example, bilharzia, sexually transmitted diseases (STDs), malaria (an endemic disease in tropical regions) and cholera (endemic in Asia).

Disease can be grouped also depending on the cause

ü  Bacterial disease: Typhoid, Cholera, TB.

ü  Viral diseases: AIDS, Polio, measles, small pox, chicken pox.

ü  Protozoan diseases: Amoeba dysentery, Trypanosomiasis (sleeping sickness), malaria

ü  Fungal diseases: Ring worms, candidiasis, athletes

ü  Genetic disease (inherited diseases): Haemophiliac, sickle cell, anaemia, down syndrome, albinism

ü  Worm diseases: Elephantiasis, bilharzia (schistosomiasis)

ü  Hormonal diseases: Diabetes mellitus, diabetes inspidus

ü  Malnutrition diseases: Kwashiorkor, obesity, marasmus, Goitre, Anaemia, Rickets

Disease can be grouped according to mode of transmission

ü  Air borne disease: Tuberculosis, common cold, influenza, whooping cough

ü  Weather bone disease: Cholera, Typhoid fever, Schistosomiasis

ü  Contaminated blood: HIV/AIDS, Malaria

ü  Physical contact (contagious disease): Ring worms, Scabies

Non- infectious (non-communicable) diseases

These are diseases which cannot be transmitted from one person to another. Examples of non-communicable diseases include:

Environmental diseases e.g.:

a)      Lung cancer

b)      Asbestosis

c)      Asthma

d)     Coronary (heart) diseases

e)      Alcoholism

Deficiency diseases

These diseases are due to lack of certain nutrients in the diet. They may be due to lack of one of the main food groups e.g.:

a)      Kwashiorkor: lack of protein

b)      Marasmus: lack of both carbohydrate and proteins

c)      Night blindness: lack of Vitamin A

d)     Beriberi: lack of Vitamin B₁

e)      Scurvy: lack of Vitamin C

f)       Rickets: lack of Vitamin D, calcium, and phosphorous

g)      Anaemia: lack of iron

h)      Goitre: lack of iodine

i)        Excessive bleeding (haemophilia): lack of Vitamin K

Genetic and congenital disorders e.g.

a)      Colour blindness

b)      Haemophilia

c)      Sickle cell anaemia

d)     Albinism

e)      Down’s syndrome

f)       Klinefelter’s syndrome

g)      Turner's syndrome

Ageing and degenerative diseases e.g.

a)      Long sightedness due to weakening of eye muscles

b)      Arteriosclerosis (hardening of arteries)

c)      Arthritis – ageing of joint and bone tissues

Mental illness e.g.

a)      Schizophrenia

b)      Senile dementia

c)      Depression

Hormonal diseases e.g.

a)      Diabetes mellitus

b)      Diabetes inspidus

c)      Cretinism

THE CAUSES, SYMPTOMS, MODE OF TRANSMISSION AND EFFECTS OF COMMON INFECTIONS AND DISEASES

CHOLERA

Cause: It is caused by a bacterium known as Vibrio cholerae

Symptoms

1.      Severe watery diarrhoea and vomiting

ü  Body weakness

ü  Fast and weak pulse

ü  Low blood pressure

ü  Wrinkled skin and sunken eyes due to dehydration

ü  Rapid loss of weight

Transmission

Cholera is transmitted through:

ü  Food or water borne material contaminated with faeces from infected person

ü  Handling of contaminated objects

ü  Vectors e.g. flies moving from human faeces to food.

MALARIA

Cause: Malaria is caused by a protozoan called plasmodium.

Signs and symptoms

ü  High fever. Fever may be continuous, irregular or twice daily.

ü  Vomiting

ü  Lack of appetite

ü  General body weakness

ü  Joint pains

Transmission

Malaria is transmitted by a female anopheles mosquito. The mosquito sucks blood containing plasmodium from the infected person and introduces them into the body of a health person. In rare cases malaria can be transmitted through blood transfusion from the infected person to a health person.

TYPHOID

Cause: It is caused by a bacterium known as Salmonella typhus. The bacteria damage the intestinal wall and other parts of the body like gall bladder, spleen and bone marrow.

Signs and symptoms

ü  Mild fever

ü  Slight abdominal pains

ü  Diarrhoea

ü  Vomiting

ü  Ulceration and rupture of intestine

Transmission

The disease is spread through

ü  Contaminated water and food

ü  Handling of contaminated objects

ü  Vectors of the disease e.g. houseflies

TUBERCULOSIS (T.B)

Cause: T.B is caused by bacterium called Mycobacterium tuberculosis. The bacteria can attack the lungs or any part of the body and destroy tissues.

Signs and symptoms

ü  Loss of weight

ü  Coughing

ü  Fever

ü  Chest pain

ü  Blood in the sputum

Transmission

ü  Through droplet infection

ü  Through drinking milk from infected cattle

ü  T.B is common in overcrowded areas with poor sanitation

APPROPRIATE PREVENTIVE AND CONTROL MEASURES FOR COMMON INFECTIONS AND DISEASES

Prevention of Cholera

ü  Wash hands after visiting toilet or latrine

ü  Food should be well cooked and drinking water should be boiled and well filtered

ü  Hands should be washed before and after eating

ü  Food should be well covered

ü  Utensils should be washed thoroughly

ü  Maintain general environmental cleanliness

Control of Cholera

ü  The infected person should be isolated

ü  Special precautions should be taken when handling the infected person

ü  Vaccination is possible

Treatment

ü  The disease can be treated by using antibiotics such astetracycline, chloramphenicol

ü  Administering rehydration salt solutions

Effects

ü  May lead to death

ü  Extra medical expenses

ü  Failure to perform daily activities

Prevention and control of malaria

ü  Spraying insecticides to destroy adult mosquitoes

ü  Introducing fish eating mosquito into stagnant water e.g. Gambusiathat feed on mosquito larvae.

ü  Draining stagnant water to remove the breeding sites for mosquitoes

ü  Use of mosquito nets to prevent mosquitoes from biting people

ü  Screening the windows with mosquito-proof wire-mesh to prevent entry of mosquitoes in the house through the windows.

ü  Wear long-sleeved shirts and trousers to prevent mosquito bites.

ü  Mosquito larvae and pupa can be killed by spraying oil into stagnant water that cannot be drained.

ü  Taking regular weekly doses of preventive drugs to kill parasites on entry.

ü  Cutting bushes around the houses to destroy shelter for mosquitoes

ü  Using mosquito repellents to flee away the mosquitoes

Treatment

Anti-malarial drugs can be used to treat the disease e.g. quinine, fansider, mefloquine, chloroquine, etc.

Effects

ü  Can cause death

ü  Can lead to mental confusion in case of cerebral malaria

ü  Paralysis and unconsciousness

ü  Drowsiness

ü  Anaemia

ü  Miscarriage

ü  Inability to participate in economic activities

ü  Increased medical expenses

Prevention and control of Typhoid

ü  Wash hands after visiting the toilet

ü  Food and water must be protected from dust and flies

ü  Wash hands before and after eating

ü  Drink boiled water and eat properly cooked food; fruits should be washed thoroughly before being eaten.

ü  Vaccination can also help to control the disease

Treatment

The disease can be treated by using antibiotics such as tetracycline, chloramphenicol, etc.

Effects

ü  Can cause death

ü  May cause ulcers and finally rupture of the intestine

ü  Enlarged spleen

Prevention and control of T.B

ü  Elimination of the conditions under which TB thrives e.g. overcrowding, poverty level living and inadequate nutrition.

ü  Observing general personal hygiene, especially when coughing and sneezing.

ü  Early BCG (Bacillus Calmette-Guérin) VaccineThe Vaccine may be used for either of two reasons:(i) Protecting newly-born babies or children at particular risk of infection.(ii) Immunization of young persons or at risk groups in the community.

ü  Keeping children, in particular, away from risk situations.

ü  The use of sterilized milk and pasteurized dairy products

ü  Contact tracing so that risk to others may be minimized

Treatment

Antibiotics such as streptomycin can be used to cure the disease.

Effects of T.B

ü  Causes a number of deaths.

ü  Abscess full of pus may form near the lump in the spine.

ü  Shortening and thickening of the chest in case of TB of the spine

Human Immune Deficiency Virus (HIV) Acquired Immune Deficiency Syndrome (AIDs)

The Meaning of HIV/AIDs, STIs, and STDs

HIV stands for (Human Immunodeficiency Virus), and AIDS for (Acquired Immune Deficiency Syndrome).

Sexually transmitted infections (STIs), also referred to as sexually transmitted diseases (STDs) and venereal diseases (VDs), are infections that are commonly spread by sex, especially vaginal intercourse, anal sex and oral sex.

TRANSMISION OF HIV

HIV (Human Immunodeficiency Virus) is transmitted via body fluids such as blood, breast milk, vaginal secretions, sweat, saliva, tears.

The most common ways of HIV transmission are:

a)    Sexual intercourse with an infected person

b)    Blood transfusion from a infected donor

c)     Organ transplants from an infected donor

d)    An infected mother to her child during pregnancy, birth or breast feeding

e)     Using unsterilized surgical or skin piercing instruments, such as scalpels, needles and circumcision blades that have been used on an affected person

f)     Sharing toothbrushes, shaving blades or nail cutter with infected person.

{HIV is not spread by casual contact such as hugging, shaking hands, or touching unless both people have bleeding injuries.}

SYMPTOMS OF HIV/AIDS

a)                   Loss of body weight by over 5kg two months

b)                  Persistent fever that lasts for longer than month

c)                   Painless flat hard lumps growing on the skin

d)                  Diarrhoea for longer than a month

e)                   Rashes on the skin

f)                   White layer in the mouth and throat

g)                  Swollen glands, especially in the neck and armpits

h)                  Coughing for more than one month

i)                    Shortness of breath gradually getting worse

j)                    Genital rashes

People with HIV and AIDS get opportunistic infections and disease, for example: -

·         Chest infections e.g. pneumonia, TB

·         Brain infections leading to mental confusion, severe headache and feet

EFFECTS OF HIV AND AIDS

ü  Stomach or gut infections leading to severe diarrhoea

ü  Skin cancer i.e. Kaposi sarcoma

PREVENTION AND CONTROL OF HIV/ AIDS

a)                   Avoid immoral sex partner prostitutes, commercial sex workers {avoid irresponsible sexual behaviour abstain from sexual intercourse {if not marriage} be faithful to one sexual partner, use condom during sexual intercourse

b)                  Wear one-use/disposable gloves when touching peoples' body fluid

c)                   Use treated instruments during surgery, circumcision and delivery

d)                  Only screened blood and organs should be used for transfusion and transplants

e)                   Go for HIV test in order to know your status and health

f)                   Do not share tooth brushes and shaving blades

g)                  People with HIV and AIDS should be given Anti-retro viral drugs (ARVS) which help them to slow down infections.

h)                  Pregnant women should attend pre natal clinic where they can be treated to prevent mother to child transmission

i)                    HIV positive mothers should not breast feed their new born babies

RISKY SITUATION, BEHAVIOUR AND PRACTICES

These are activities and situation that put us at greater risk of being infected with STIS, STDS and HIV these include: -

ü  Blood transfusion using unscreened blood

ü  Drinking alcohol, smoking using drugs such as Marijuana(bangi), heroin and cocaine

ü  Immoral friends who influence to use drug abuse, engage in sex earlier

ü  Having many sexual partners having insecure sex

ü  Sharing sharp object and toothbrushes.

HOW TO AVOID RISKY PRACTICES BEHAVIOUR AND SITUATION

1)     Practising safe sex

2)     Applying non- penetrative sex e.g. kissing, hugging, etc.

3)     Delaying technique e.g. I’m required at home just now let’s meet tomorrow

4)     Discouraging/negative words e.g. I’m HIV positive

5)     Discouraging peer pressure

6)     Engaging in sports and games which distract one’s mind from concentrating to sex.

CARE AND SUPPORT OF PEOPLE LIVING WITH HIV/AIDS (PLWHA)

People with HIV and AIDS can live health life for a period of long time if they get proper care and support we can care for them and supported them in the following ways:

ü  Give them well balanced diet in adequate quantities.

ü  Allow them to rest when they feel sick.

ü  Taking them to a health centre as soon as they start rising signs of illness.

ü  Provide them with ARVS, allow them to work.

ü  Acting in a loving way towards them and listen them.

ü  Counselling them to stop behaviour that worsen

ü  Not discriminating against them or stigmatizing

ü  Hiding them from the public, denying them education or health services

ü  Chasing them away from home

ü  Refuse to share utensils or rooms with them

Care and support gives People Living with HIV and AIDS (PLWHA) courage, good health piece of mind, long life strength to work and comfort

Importance of care and support to people living with HIV/AIDS (PLWHA) include the following:

a)      It enables them to prolong their lives in case they are administered with ARVs.

b)      It reduces fear of death.

c)      It enables them to perform their daily activities without fear.

d)     It reduces depression and self-dislike.

CELL STRUCTURE AND ORGANIZATION

The Cell is a basic unit of life.

ü  All living things are composed of cells.

ü   All cells are basically the same in chemical composition. All life processes take place in the cells.

ü  Some organisms are made up of many cells and are called multicellular organisms e.g. man, pine tree, locust. Others have one cell e.g. Amoeba, they are called unicellular organisms.

ü  All cells are microscopic, its membrane bound it has structures that are site for chemical reaction called organism.

ü  They have ability to replicate, since they contain the genetic materials. So these are characteristics of cell.

Characteristics of the cell include the following:

a)      Cells are small microscopic structures which cannot be seen by our naked eyes.

b)      Cells are capable of dividing by mitotic process or meiotic process.

c)      Cells contain structures called organelles.

TYPES OF CELLS

There are two basic types of cells.

a.       Prokaryotic cells

b.      Eukaryotic cells

Prokaryotic cells are cells with no membrane-bound nucleus. The DNA lies free in the cytoplasm in a region known as nucleoid. They have no true nuclei. Examples of prokaryotic organisms are bacteria.

Eukaryotic cells are cells whose nuclei are bounded by nuclear membrane. They are surrounded by two nuclear membranes called nuclear envelope. Examples of eukaryotic organisms are protoctists, fungi, plants and animal cells.

Differences between Prokaryotic and Eukaryotic cells

Eukaryotic cells	Prokaryotic cell
They have nuclear membrane	Lack nuclear membrane
Organelles are surrounded by envelopes	Organelles are not surrounded by envelopes
Have true nucleus	Have no true nucleus

ANIMAL AND PLANT CELLS

Both animals and plants differ in structure and function in order to be able to meet the requirements of each organism

PLANT CELL

FUNCTION OF THE PARTS OF ANIMAL CELL

ANIMAL CELL

FUNCTION OF THE PARTS OF PLANT CELL

1.                   CELL MEMBRANE

ü  Is also known as plasma membrane or plasma lemma.

ü  Is thin layer that encloses the whole cell

ü  Communicate with other cells.

ü  It allows selective movement of substances into and out of the cell. It is said to be a selectively permeable membrane or differential membrane

ü  It encloses the contents of the cell.

2.                   CYTOPLASM

Cytoplasm is a transparent jelly-like fluid and may contain particles such chloroplasts or starch grains or oil droplets. It contains up to 80% water and the remainder is mainly protein. It is a place where chemical reactions take place

3.                   NUCLEUS

A nucleus is a ball-shaped or oval body located inside the cytoplasm. It cannot usually be seen unless the cell has been stained with certain dyes. It consists of nucleoplasm bounded by nuclear membrane. The nucleus is a cell control centre.

The following are the functions of the nucleus:

ü  It controls the formation and development of a cell.

ü  The nucleus also controls chemicals which the cell manufactures.

ü  The nucleus contain chromosomes which carry genetic material i.e. DNA which is responsible for controlling genetic information.

4.                   CELL WALL

The cell wall is only found in plant cells. It is made up of cellulose. When the cell is growing the cell wall is fairy plastic and extensible. It becomes tough and resists stretching when the cell has reached full size. The cell wall is non-living. It has the following functions:

ü  It gives the cell its shape.

ü  It is freely permeable to all kinds of molecules.

ü  It supports and protects the cell.

ü  It supports non-woody plant organs, such as leaves, by turgor pressure.

ü  It osmoregulates by resisting entry of excess water into cell.

5.                   VACUOLE

In animal cells, vacuoles are small droplets of fluid in the cytoplasm variable in size and position. In plant cells, the vacuole is a large, permanent fluid-filled cavity which occupies a greater part of the cell. In plants, the fluid is called cell sap. The cell sap may contain salts, sugar and pigments dissolved in water.

The vacuole performs the following functions:

ü  It is responsible for food storage and osmoregulation.

ü  The outward pressure of the vacuole on the cell wall makes the plant cells firm, giving strength and resilience to the tissues.

6.                   MITOCHONDRIA

The function of mitochondrion is the site for respiration, reactions which yield energy for the cell.

7.                   CHLOROPLAST

They are sites of photosynthesis

ü  It contains green pigment called chlorophyll.

ü   Chlorophyll absorbs the light energy needed for photosynthesis

8.                   RIBOSOMES

This is the site of protein synthesis.

SIMILARITIES BETWEEN PLANT AND ANIMAL CELL

ü  Both have cell membrane.

ü  Both have cytoplasm.

ü  Both have nucleus.

ü  Both have vacuoles

ü  Both have ribosomes and mitochondria.

Differences between plant cell and animal cell

Plant cell	Animal cell
Has a cell wall	No cell wall
Has chloroplast	Lacks chloroplast
Have definite shape	Have no definite shape
Has a large permanent vacuole	Has small temporary vacuole
They are normally large	They are usually smaller
They store oil, proteins, starch	They store fats and glycogen
The nucleus is located at the periphery	The nucleus is centrally located

CELL DIFFERENTIATION

Cells have different functions and features that make them better suited to carry out these functions. This is called cell differentiation.

Most living things are made up of many structurally and physiologically adapted different kinds of cells.

These cells perform specific function and this is referred to as cell specialization.

Cell differentiation refers to the way cells are adapted so that they can carry out function efficiently.

TISSUE

A tissue is a group or collection of similar cells performing a specific function. Tissues vary in size, shape and function.

 There are two types of tissue.

Animal tissue e.g. epithelial tissue, muscular tissue, blood tissue, nerve tissue, skin tissue.

Plant tissue e.g. parenchyma tissue, collenchyma tissue, vascular tissue (xylem tissue, phloem tissue).

ORGAN

An organ is a collection of tissues working together to perform a certain function.

Animal organ: - heart, kidney, liver, brain, tang, stomach, ears

Plant organ: - roots, leavers, flower, stem, fruits

SYSTEM

A system refers to several inter-related organs performing a particular function.

Examples of system are Respiratory system, digestive system, reproductive system, hormonal system, skeletal system and blood circulatory system, nervous system.

ORGANISM

An organism is the individual living organism e.g. Animal and Plant.

An organism is made up of different systems working together therefore there is special

Tissue

Organization from the cell      —►    tissue   —► organ —► system —► Organism

IMPORTANCE OF CELL DIFFERENTIATION

Cell differentiations leads to division of labour.

Division of labour means each cell does a specific function. This helps the body to carry out all life processes at the same time and more efficiently.

To achieve this, cells must become specialized to carry out special functions.

More about specialized cell for different function e.g.

White blood cell (WBC) can change their shape to engulf and destroy harmful pathogen.

Red blood cell (RBC) for transporting oxygen (they are biconcave and lack nucleus)

Sperm cell: Fertilizes the female egg (have tails for swim pointed head for easy penetration)

Root hair cells:  for absorb water and mineral salts (have extended portion helps to increase surface area for absorption)

Guard cell: control open and close of stomach (the inner wall is thinker than outer)

Palisade cell: makes it to expand irregularly

CLASSIFICATION OF LIVING THINGS

Classification is the system of sorting out and placing organisms into different groups on the basis of their similarities and differences. These similarities could be in terms of origin structure or the way they carry out life processes such as feeding and reproduction.

Classification is a branch of biology that deals with the grouping of living organisms according to their structure, way of life and origin.

Taxonomy- it is a branch of biology that deals with classifying organisms.

Taxonomist- A person (biologist) who studies about classification.

Taxon- is any named established group in the ranks of classification.

IMPORTANCE OF CLASSIFYING LIVINGTHINGS

1.      Classification makes the study of living things easy

2.      Classification makes communication easy among biologists from different parts of the world

3.      It provides good organized system in which a newly identified organism can be easily fitted in future.

4.      It makes it easier to identify organisms

5.      It can be used to predict characteristics that are present in the members of the same group.

CLASSIFICATION SYSTEM

There are two types of classification:-

a.       Artificial classification

b.      Natural classification

ARTIFICIAL CLASSIFICATION

Artificial classification system is grouping of organism according to observable characteristics. For instance presence of legs or wings on bees, birds and bats would be grouped together because they possess wings. Snakes, earth worm and snails would also be grouped together because they do not have legs.

Artificial classification also includes classifying organisms according to their size how they move, where they live or what they eat.

Advantage of artificial classification

ü  It is easy to classify organisms since it is based on few observable characteristics.

ü  It does not take much time to classify organisms based on this system (not time consuming).

ü  It does not need expertise (even a layman can do).

ü  It is relatively stable i.e. not easily changing from time to time.

Disadvantages of artificial system of classification

ü  It tends to place closely related organisms into different groups instead of being grouped together e.g. a bat can be placed in a group of birds instead of mammals.

ü  Different or unrelated organisms may be placed in the same group e.g. bats placed in a group of birds, worms placed with snakes in the same group

ü  The system does not provide enough information about its members.

ü  It is difficult to incorporate additional information.

NATURAL CLASSIFICATION

In this system classification is based on evolutionary relationship and presence of large number of common and similar features that show homology and analogy structure.

Homologous structures: Are the structure having the same origin but perform different function. E.g., Forelimbs of whale and forelimbs of man

Analogous structure; Are structure having different origin but perform the same function.E.g. Wings of birds and wings of insect

Advantages of natural system of classification

ü    Closely related organisms are placed in the same group.

ü    It reflects evolutionary relationships.

ü    Unrelated organisms cannot be placed in the same group.

ü    It makes it easy to incorporate additional information.

Disadvantages of natural system of classification

ü    It is difficult since it considers many features.

ü    It requires expertise i.e. more knowledge about an organism.

ü    It is time consuming.

ü    It is relatively unstable i.e. it changes from time to time.

ü    It is more expensive since more data are required.

             Differences between natural classification and artificial classification

Artificial classification	Natural classification
Considers few features in common	Considers many features in common
Does not reflect on evolutionary relationships	Reflects on evolutionary relationships
It is easy to classify	It is difficult to classify
Not time consuming	It is time consuming
Does not require expertise	Requires expertise
New information cannot be added	New information can be added.

MAJOR GROUPS OF LIVING THINGS

There are five major groups of living organisms

1)                  Kingdom animalia e.g. Cow, cockroach

2)                  Kingdom plantae e.g. Maize tree, peas

3)                  Kingdom monera e.g. Bacteria

4)                  Kingdom protoctista e.g. Amoeba

5)                  Kingdom Fungi e.g. yeast

RANKS OF CLASSIFICATION

1)      Kingdom

2)      Phylum/division

3)      Class

4)      Order

5)      Family

6)      Genus

7)      Species

The highest rank of classification is the kingdom. The lowest rank of classification is the species. At kingdom level, organism shows few features in common as you move down the rank each unit has lesser organisms and the members of each unit have more  features in common Every known organism has particular place in each group.

1)      Kingdom- this is the highest rank (taxon). It comprises of several related taxa. It comprises of many organisms than any other taxon.

2)      Phylum/division– this is the second largest rank of classification. It consists of several closely related classes.

3)      Class - members or this group have more characteristics in common than do members of division or phylum.

4)      Order- it consists of groups that are more alike than those in a class.

5)      Family –this is made up of groups that are more alike than those in the order. Wolves and cats are both in the order Carnivore but wolves are in the family Canidae while cats belong to the family Felidae.

6)      Genus – it consists of very similar species but members of different species cannot breed one another.

7)      Species – Species can be defined as a group of closely related organisms which are capable of interbreeding and produce fertile offspring

Classification of Some Members of Common Organisms

Taxonomy Unit	Human Being	Dog	Maize Plant	Eucalyptus Tree
Kingdom	Animalia	Animalia	Plantae	Plantae
Phylum or division	Chordata	Chordata	Spermatophyta	Magnoliophyta
Class	Mammalia	Mammalia	Argiospermae	Magnoliopsida
Order	Enirate	Carnivore	Graminales	Myrtalesa
Family	Hominidae	Canidae	Graminales	Myrtaceae
Genus	Homo	Canis	Zea	Eucalyptus
Species	Sapiens	Familiars	Mays	Regnans
Scientific name	Homo sapiens	Canis familiaris	Zeamays	Eurcalyptus regnans

KINGDOM

For example human being, donkey and cow

-Kingdom Animalia is subdivided into phyla or phylum in singular

-Kingdom Plantae subdivided into division, The phyla or division are further subdivided into class, each classes is subdivided into orders every order is subdivided into families and families are subdivided into genera (genus in singular)

-A genus is subdivided into species.

Kingdom à phylum à divisions à classes à orders à families à genera à species

These ranks of classification and are called units or taxa.

The chart below shows how kingdom Plantae and kingdom Animalia are subdivided

 

                                                                         Class

 

Order

 

Family

 

Genus

 

Species

BINOMIAL NOMENCLATURE

Nomenclature is a scientific process of naming organisms where by every name is made up of two Latin words.

This system was divided into two parts

The first part of the name represents the genus it is also called the genetic name.

The second part of the name represents the species it is also called the specific names

For example: The specific name of human being is Homo sapiens. Homo is generic name and sapiens is the specific name. The following rules are observed when writing scientific names.

a)      Scientific names of organisms must be in Latin language and if the names are derived from other languages, they must be Latinised

b)      The generic name is written before the specific name

c)      The generic name must start with capital letter.

d)     The specific name is written in small letter

e)      In publisher document such as books scientific name is written in italics e.g., Zea mays and Homo sapiens when hand written or typed the names should be underlined.

              SCIENTIFIC NAMES OF SOME COMMON ORGANISMS

COMMON NAME	SCIENTIFIC NAME
Coconut plant	Cocos nucifera
Mango tree	Mangifera indica
Garlic plant	Allium sativum
Pea plant	Pisum sativum
Domestic cat	Felis catus
Housefly	Musca domestica
Lion	Panthera leo
Donkey	Equus asinus
Earthworm	Lumbricus terrestris
Cockroach	Periplaneta americana
Amoeba	Amoeba proteus
Coffee	Coffea  arabica
Bean	Phaseolus vulgaris

VIRUSES

A virus is an extremely small microorganism.

It is smaller than a living cell. A virus is not a cell.

Virology: means the study of viruses.

                  

DIFFERENT TYPES OF VIRUSES   

                                  Bacteriophage Virus                                             

                  

The Structure of Viruses

Generally viruses have a very simple structure consisting of the following:

a)                  RNA or DNA which may be single stranded or double stranded. They form a structure called core.

b)                  A protective coat of protein surrounding the core called capsid.

c)                  A nucleocapsid which is a combined structure of core and capsid.

d)                 Envelope – an additional layer of lipoprotein layer around the capsid.

e)                  Capsids are made up of identical repeating units known as capsomeres.

CHARACTERISTICS OF VIRUSES

1)                  They are the smallest living organisms ranging from 20-30nm. On average, they are about 50times smaller than bacteria.

2)                  Viruses do not have cellular structures, which mean that they lack certain important organelles like nucleus, cytoplasm, golgi bodies, etc.

3)                  They can only reproduce inside the living cells hence they are parasitic.

4)                  They have a simple structure consisting of either DNA or RNA but not both, surrounded by a protein or lipoprotein coat.

5)                  They can be described as living or non-living.

6)                  They are highly specific to their hosts i.e. each virus recognizes only certain types of cells.

7)                  Viruses are capable of replicating themselves only when they are inside the host cell.

Advantages of viruses

1)      Viruses are used in developing vaccines, for example, vaccines for measles, polio and rubella are made from viruses that have been attenuated (weakened).

2)      Viruses are used as biological weapons to kill organisms.

3)      They are used as vectors in genetic engineering to transfer genes from one organism to another for improving or treating the defective genes.

4)      Bacteriophages are viruses that attack bacteria and hence they help in controlling infections and diseases.

5)      Viruses are used as biological weapons in wars and in biological pest control.

Disadvantage of virus

a)                  Viruses are pathogens, they cause disease and infections such as rabies, muscles, chickenpox and polio also they destroy living cell.

b)                  They can replicate very fast, leading to large scale epidemics.

c)                  Viruses can attach themselves often and this become difficult to destroy for example there are many different types of viruses that cause the common cold and influenza. This makes it difficult to develop vaccines or cures for these infections.

KINGDOM MONERA

This kingdom monera consists of bacteria and blue green bacteria.

The scientific study of bacteria is called bacteriology

CHARACTERISTICS OF KINGDOM MONERA (BACTERIA)

a.       They are mainly unicellular and very small.

b.      They are all prokaryotic (nucleus not bound by membrane)

c.       They reproduce by binary fission.

d.      Some members of the kingdom are autotrophs while others are heterotrophs

e.       They have cell wall made up of protein material and sometimes lipids.

f.       Some bacteria form spores during adverse conditions i.e. extreme conditions e.g. high or low temperatures, drought etc. The spores allow them to survive as they have very thick resistant walls.

g.      Some are aerobes while others are anaerobes.

h.      The genetic material (DNA) is scattered in the cytoplasm and they lack internal membrane bound organelles such as mitochondria, chloroplasts, Golgi bodies etc.

Forms of bacteria

Bacterial shape is an important aid to classification. There are four main shapes

Coccus (plural: cocci)

They are spherical in shape and can be of the following types.

Micrococcus – exist singly. They cause sore throat.

Diplococci - this type of bacteria exist in pairs. The pneumococci (Diplococcus pneumoniae) are the only members. They cause pneumonia.

Streptococci – this type of bacteria stick together and form a chain. Most of them infect upper respiratory surface and cause diseases e.g. sore throat.

Staphylococci – These bacteria form a grape like bunch. They cause boils, pneumonia, food poisoning and other diseases.

Bacilli (singular: bacillus)

These are rod shaped bacteria. They can be:

Single rods, for example, Escherichia coli commonly living in the gut and Salmonella typhi which cause typhoid fever.

·         Rods in chain, for example, Azotobacter, a nitrogen-fixing bacteria, and Bacillus anthracis which cause the disease anthrax.

·         Bacilli with endospores showing various positions, shapes and sizes of spores. They can be:

a.       Central, not swollen e.g. Bacillus anthracis causes anthrax

b.      Spherical spore, terminal swollen e.g. Clostridium tetanicauses tetanus

c.       Sub-terminal, swollen e.g. Clostridium botulism causes botulism.Spores may also be central

Spirilla (singular: spirillum)

These are spiral-shaped bacteria e.g. Treponema pallidumwhich causes syphilis

Sprrilla

Vibrio

These are comma shaped bacteria, for example Vibrio cholerae.

Vibrio cholera

-A bacterium consists of nucleic materials suspended in the cytoplasm, (no nucleus)

-The cytoplasm is enclosed by fold cell membrane; a cell wall and slim layer enclose the cell membrane.

     

Pathogenic bacteria

These are bacteria that can cause sickness, some of the sicknesses caused by bacteria are fire blight, ring rot and tobacco mosaic in plant and TB, cholera, typhoid, tetanus, syphilis and gonorrhoea in animals.

Fimbriae or pili

These are hair like structure found on bacteria. The hairs attach themselves to the host so that they cannot be removed easily. e.g. Escherichia coli produce fimbria that attaches themselves the living of the urinary track or the intestines.

Fimbriae or pili

FLAGELLA

These are long tail like structures that enable some pathogenic bacteria to move to a site where they can services

TOXINS

Some bacteria produce poisonous compound that harm hosts. In human these toxins cause effects such as vomiting diarrhoea, fever and muscle cramps for instance, toxins released by salmonella bacteria can cause severe diarrhoea.

Invasion and colonization

Some bacteria attack themselves and become unaffected to modes of treatment for examples, the bacterium they causes tuberculosis has become resistant to many antibiotics by changing itself.

Some types of bacteria release a substance known as bio film that protects them from dangerous substances such as drugs