GAIRO DISTRICT COUNCIL

FORM FOUR PRE-MOCK EXAMINATION

MARCH- 2024
SUBJECT CODE: 033/1 BIOLOGY 1.
SECTION A
1. Multiple choice (01@=10marks)

i ii iii iv v vi vii viii ix x

B D A C B D C C A C

2. MATCHING ITEM @ 1MARK (TOTAL 6 MARKS)

LIST A (i) (ii) (iii) (iv) (v) (vi)

LISTB E A H F G L

3. (i) Sorting organisms

LIVING NON LIVING

Baobab tree Cars

Mango tree Stones

Butterfly Gravels

Birds Pebbles

Dogs Water streams

i) A student should mention any Two (02) characteristics of living things

o They can move

o They can reproduce

o They can eat/feed
o They can excrete wastes
o They can breath
o They grow
o They sense
o They can respire

ii) The student should mention any Two (02) points

o They can not move

o They can not reproduce
o They can not eat/feed
 o They can not excrete
o They can not breath
o They can not grow
o They can not sense
o They can not respire

4.

(I) Ways of managing wastes

o Using pit latrines

o Using dust bins
o Using damping sites or open holes
o Using landfill sites
o Burning wastes ( any 03 points, 11/2 @ mark= 03)

(II) Benefits of proper waste management

o Prevents the spread of diseases and infections such as cholera, diarrhoea and typhoid
o It prevents occurance of accidents such as cuts from peaces of broken grasses
o It prevents air pullution and reduce bad smells in the environment which can cause incomfotability
o It keeps our water bodies in good condition and prevents the harm of polluted water to human
population, domestic animals and non-domestic animals. (Any 03 points 11/2 @marks=4.5)

5. A student should predict (give 6) possible factors which might have caused Bwanaheri to look older than his actual
age such as

I. Poor diet/ lack of balanced diet which causes the body lack some nutrients
II. Diseases which weakens the body cells and make them possible to divide to accelerate growth by firming
new cells
III. Stress weakens the body immunity and make the body prone to diseases and infections which affect the
body cells and so affects growth eventually
IV. Hereditary diseases such as Warner's syndrome which causes pre mature ageing
V. Drug abuse, the illegal use of drugs weakens the immune system and cause pre- mature ageing
VI. Smoking, this reduce the life span and accelerates the formation of ageing features due to dying of some
cells in the body. It reduces life span by twelve 12 years.
VII. Poverty, low income may cause people to fail to obtain the basic needs for example proper medical care,
balanced diet so resulting into early ageing. (any 6 points, 11/2 @marks)
6. (a) (i) Food web

Vulture

Hen

Grasshopper lizard

Human being ( 3.5 mark)

Goat

Grass

(ii) (a) producer(s)

- Grass (1.5 mark)

(b) Primary consumers

-Goat, grasshopper (1.5 mark)

(v) Decomposers (Bacteria or Fungi) (1.5 mark)

(b) (i) Parasitism is the type of symbiotic relationship between two organisms the parasite and host. Mosquito and
human being and tick and cow (1 mark)

7. (i) The student should analyse three (03) types of excretory products excreted by higher animals like human, fish,
lizards birds like;

(i) Ammonia: excreted by fish due to its high toxicity levels they require a lot of water to be excreted so for
fish it's aesy because they live in water

(ii) Urea: excreted by amphibians and mammals like human being which live in terrestrial environment
bacause urea is less toxic compared to ammonia.

(iii) Uric acid: excreted by insects, reptiles and birds which consume a little amount of water due to its less
toxic nature and low solubility its excreted in paste form to allow water be conserved

(iv) Excess water: due to the complexity of the body structure a lot of metabolism take place and produce
excess water Which is excreted in form of sweet or urine

(v) Carbon dioxide: higher animals requires a lot of energy to operate so as respiration occurs it results into
production of carbon dioxide gas which is toxic to body cells. (Any 03 points 2 marks @= 06 marks)

(ii) A student should Cite any (03) organs used by higher animals for excretion including

o Lungs
o Kidney
o Skin
o Liver (any 03 points 1mark@= 03)
 8. (a) SS ss
Meiosis

Gametes S S s s

Fertilizatio
n
F1 Generation Ss Ss Ss Ss (1marks)
𝟏
(a) Genotype for the F1 all are Ss (smooth but carrier) ( 𝟐 mark)

(b)
Genotype Ss Ss

Meiosis

Gametes
S s S s

Fertilization

F2 generation SS Ss Ss ss ( 1marks

(b) (i) Phenotypes

3 Smooth seed coat and 1 Wrinkled seed coat .( 1 mark)

(ii) Genotypes
𝟏
the Genotypes are 1SS, 2Ss and 1ss .( mark)
𝟐

𝟏
(iii) Genotypic ratio 1:2:1 .( mark)
𝟐

𝟏
(iv) phenotypic ratio 3:1 .( 𝟐 mark)

(c) (i) Total number of wrinkled seed

From the ratio 3:1

1
4
× 7324 = 1831

Total number of wrinkled seed in F2 is 1831 (2marks)

(ii) Total number of smooth seed in F2

From the ratio 3:1

3
4
× 7324 = 5493

Total number of smooth seed coat is 5493 (2marks)

 9. The student should describe five (05) points on how our bodies defend themselves against any harm which can be
caused by micro-organisms in our health

INTRODUCTION ( 3 marks):

The student should give any relevant information on the body defense system

Body defense system is a system in the body which helps the body to prevent entrance of micro-organisms in the
body. It involves some parts such as skin, eyes, ears, digestive system and blood.

MAIN BODY (2marks@= 10)

The student should describe five 05 points on how the body defense system works

Skin: it acts as a barrier against entry of microorganisms. The glands on the skin like sweat glands and sebaceous
glands secrete sweat and sebum oily which contains antibacterial agents that kills bacteria

Eyes: the parts of the eyes like eyelashes, eyelids and eyebrows prevent the entry of dust which contains micro-
organisms like bacteria. Tears glands also secrets tears which contains antibacterial agents.

Ears: the outer ear canal produce wax material which traps bacteria, virus and small dust particles

Digestive system: Different regions of the digestive system produces and contains glands secretions which help
in the body defense. Salivary glands for example secrets saliva which is a mild antibacterial agent, the harmless
bacteria Which live in the mouth also protect it from various infectiy. In the stomach the hydrochloric acid secreted
by stomach walls kill most of bacteria taken in with food. The intestinal juice contains antibacterial properties.

The blood: The blood is made up of white cells, lymphocytes and phagocytes which works together on defending
the body. The lymphocytes provide antibodies that destroy pathogens while the phagocytes engulf and remove
micro-organisms which invides the body.

Ciliated membrane, the presence of cilia in some parts of our bodies example in nose. The cilia trap dusts and
bacteria which should be given out through sneezing and coughing.

CONCLUSION

Any relevant conclusion

Example

It is important for us to take care of our bodies by following proper hygiene conditions and eating balanced diet
to strengthen the body defense. No

10. Bacteria is a single- celled organism which belongs to Kingdom Monera, there are useful bacteria to man and others
are harmful to man example; Escherichia coli which live in the gut of human being to help in digestion and other
example Azotobacteria which is helpful in nitrogen fixation but other that cause diseases are Vibrio cholera Salmonera
typhii and mycobacterium tuberculosis. TB (2marks)

Usefulness

 Bacteria provide vital ecosystem services. They are important decomposers relationships
 They are useful for the carbon and nitrogen cycles eg. Nitrogen fixation bacteria.
 The bacteria found in the human digestion system or fruit they are helpful in digestion process
  Human also use bacteria in many ways (other ways) including
 Creating product such as ethanol and enzymes
 Making drags such as ant-biotic and vaccine
 Making biogas such as methane
 Cleaning up oils spills and toxic waste ( Any three points @02 marks)

Harmfulness of bacteria
 They spoil food, some bacteria spoil and destroy food
 Some bacteria cause diseases to human being and othe organisms eg of diseases include tuberculosis, typhoid,
pneumonia
 Some bacteria can cause tooth decay ( Any three points @02 marks)

Conclusion
Bacteria have both usefulness and harmful effects but useful bacteria are very important in real life and helps
human in various aspects ( 1mark)

11. A student should describe the mechanism of hearing which enabled James to hear it's voice

A student should describe what mechanism of hearing (1mark) is

A student should mention the organ responsible for hearing(1 mark)

(i) Pinna collects sound waves from the sorroundings and direct them to the middle ear through the external
auditory canal or auditory meatus.

(ii) The eardrum vibrates on receiving the sounds

(iii) The vibrations of the eardrum cause disturbance to the ear ossicles malleous,incus and stapes which
makes them vibrate and transimit the sound waves to the inner ear through the oval window.

(iv) The vibrations of the oval window are transimitted to the cochlea and cause the fluid in the cochlea
(perilymph) to vibrate and create up pressure and vibrations which stimulate the sensory hair cells to
create nerve impulse .

(v) The nerve impulse created will be sent to the brain by the auditory nerve for interpretation.

(vi) The brain will interpret the impulse and send the feedback to which type of sound is that .

(6 points@2marks=12marks)

Through this steps James was able to hear the voice of the lion.(Conclusion 1mark)