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BIOLOGY PAPER ONE- MARKING SCHEME
1. Name the branch of biology that deals with the study of;
a). Cells
1 Mark
Cell biology
b). Parasites
1 mark
Parasitology
2. The diameter field of view of a light microscopic is 3.5mm. Plant cells lying within of the
diameter are 10. Determine the size of one cell microns (1mm = 1000µm).
2 marks
1 mm = 1000μm
3.5 mm = 3500 μm
10 cells = 3500 μm
1 cell = 3500 μm
10
1 cell
= 350 μm
3. The table below shows the concentration of some ions in pond water and in the cells sap
of an aquatic plant growing in the pond.
Ions
Sodium
Concentration in pond
Concentration in cell
water (parts per million)
sap (parts per million
50
30
Potassium
2
150
Calcium
1.5
1
Chloride
180
200
a)
Name the processes by which the following ions could have been
taken up by this plant.
(2mks)
i)
Calcium
Diffusion
ii)
Potassium ions
Active transport
b. Give one condition required for the process named in a (ii) above.
1 Mark.
Energy is required/ATP
Food/Glucose
Oxygen
4. An experiment was set up as shown in the diagram below.
Mark first one only
The set up was left for 30 minutes.
a)
What was the aim of the experiment?
(1mk)
To demonstrate osmosis using non living tissue
b). Give TWO importance’s of the process being investigated above in plants (3mks)
Plants roots absorb water from the soil
Feeding by insectivorous plants
Opening and closing of stomata
5. Photosynthesis takes place in two stages. Name the part of the chloroplast where
i)
Light stage occurs
1 mark
Grannae/Grannum
ii)
Dark stage occurs
1mk
Stroma Rej stoma
6. Give the food requirements whose deficiency in the human diet causes each of the
following disease.
a). Scurvy
(1mk)
Vitamin C
b). Goitre
Iodine
(1mk)
c). Night blindness
Vitamin A
(1 mk)
Rej: Vitamin a
7. The diagram below represents a transverse section of a young stem.
a)
Name the parts labelled A and B
A.
Epidermis
B.
Pith
b) State the functions of the parts labelled C.
(2mks)
(1mk)
Transports manufactured food/Translocation
8. A Form one student lit up a charcoal jiko in a room, closed all the windows and the doors
in an attempt to keep warm. The student died after 6 hours.
(3mks)
Carbon (II) oxide gas produced by the burning charcoal, combined with oxygen gas to give
carboxyhaemoglobin which is very stable/does not easily dissociate in the tissues,
hence leading to suffocation
and eventually death
9. Name three gaseous constituents involved in gaseous exchange in plants.
Oxygen
Carbon(IV)oxide
Water vapour
(3mks)
Rej: Chemical formulae
Rej: water
10. What is the effect of contraction of the External intercostal muscles during breathing in
mammals?
(3mks)
Rib cage moves upwards and outwards
Internal volume increases
Internal pressure decreases
11. a). Name the chemical compound that accumulates in the human body muscles during
a vigorous exercise.
(1mk)
Lactic acid
b). What is the effect of the accumulation of the compound named in (a) above. (2mks)
It is poisonous to tissues
Causes muscle crumps
Increases heart beat
Mark any correct two
12. Below is a diagram of an organelle that is involved in aerobic respiration.
a)
Name the organelle
(1mk
Mitochondrion Rej: Mitochondria
b)
What is the purpose of the folding labelled D?
(1mk)
To increase surface area for attachment of respiratory enzymes/To increase
surface area for respiration
c)
Give the chemical compound which is formed in the organelle and forms the
immediate source of energy.
(1mk)
Adenosine triphospahate/ATP
13. The temperature of a person taken before during and after taking a cold bath. The
results are shown in the graph
37
Temp 0C
36
35
Time (Minutes)
(a)
Explain why the temperature fell during the bath
( 2 marks)
Heat from the body metabolism is not lost to the surrounding through
sweating, because evaporation of sweat will be low; as air is already saturated
with moisture
b) Give the name of the thermoregulatory centre in the human body. (1mk)
Hypothalamus
15. The diagram below represents a fern
Name
(a) Parts labelled A and B
( 2 marks)
A. Sorus
B. Rhizome
(b) The division which the plant belongs
( 1 mark)
Ptreridophyta Rej: Pteridophyte
16. What three characteristics are used to divide the arthropods into classes?
Number of body parts
Number of appendages
Presence of wings
(3 mks)
17. The graph below represents a population growth of a certain herbivore in a grassland
ecosystem over a period of time.
Suggest three factors that could have caused the population change between C and D
(3mks)
Drought/food shortage /overgrazing
Fire
Emigration
18. The chart below shows a feeding relationship in a certain ecosystem
Grasshopper → Lizards → Snakes
Green plants
Hawks
Mice
Domestic cats
a). Construct one food chain ending with a tertiary consumer
Green plants → Grasshoppers → Lizards →
Snakes
Green plants → Grasshoppers → Lizards → Cats
Green plants → Mice → Snakes → Cats
(1 mk)
Mark any one correct
(a) Which organism has the largest variety of predators in the food web?
(1 mk)
Mice
(b) Name two secondary consumers in the food web
( 2 marks)
Lizard
Snake
Mark first two only
Domestic cat
Hawk
19. Give three advantages of cross- pollination
( 3 marks)
Promotes variations/ Mixing of genetic composition of different plants.
Promotes hybrid vigour/Offspring produced has high yield.
Offspring is more resistant to disease and adverse conditions
20. State two roles of placenta in mammals
(2mks)
It forms a large surface area for the diffusion of nutrient from the maternal blood to the foetal
blood. Glucose, amino acids and salts are transferred.
The placenta isolates the foetus from the higher blood pressure of the mother and from
direct connection of the two blood systems.
Acts as an excretory organ/Excretion materials can easily pass from foetus to
mother.
21. Green plants grow towards a source of light. Name this type of response
(1mk)
Phototrpism
22. State two characteristics that researchers select in breeding programmes. (2marks)
-High yielding /Hybrid vigour
- Resistance to disease,
Mark first two only
- Early maturity.
- Resistance to drought
23. Give an example of sex- linked trait in humans on;
( 2 marks)
Y chromosome: Hairy pinna, tuft and hair sprouting from the pinna, baldness.
X chromosome: Colour blindness; Haemophilia
24. State two advantages of natural selection to organisms
( 2 marks)
Assists to eliminate disadvantageous characteristics / perpetuate advantageous characteristics.
- Allow better-adapted organisms to survive (adverse changes) in environment/less adapted
organisms are eliminated by adverse changes in the environment.
25. Study the diagram below and answer the questions that follow.
a). Identify the structure.
(1 mk)
Motor neurone
b). With an arrow, indicate on the diagram the direction of the impulse through the neurone
(1mk)
(c)
State the functions of parts labelled P
( 1 marks)
Insulates the axon
26. (a) State the functions of the following parts of the mammalian ear
(i) Tympanic membrane
(1mk)
Receive sound waves
Transforms sound waves into vibrations
Transmit vibration to the ear ossicles
(ii) Eustachian tube
(1mk)
Equalizes the air pressure in the middle ear to that in the outer ear.
(iii) Ear ossicles
(1mk)
Amplify/ transmit vibrations from the tympanic membrane in the inner ear.
27. Nocturnal animals such as the domestic cat are capable of seeing fairly well at night.
What two retinal adaptations have made this possible?
(2mks)
Presence of rods having rhodopsin pigment that is sensitive to dim light.
Rods are more sensitive to motion and easily note movement from the cornea of the eye.
More than 120 million rods present on the retina/Large number of rods on the retina.
28. The diagram below represents in a mammalian bone
(a) State the function of the part labelled K and L
( 2 marks)
K - (Facet) for articulation, with the next vertebra
L – (Transverse process) for attachment of muscles
(b) State the region of the body in which the bone is found
(1mk)
Cervical / neck region
29. Name the three types of skeletons found in multicellular animals
(3mks)
Hydrostatic
Exoskeleton
Endoskeleton
30. Name the three main types of joint
Immovable joints
Synovial (movable) joints)
(3mks)
Glinding/ sliding joints
31. Name the structures used for locomotion in each of the following organism
(a) Euglena
( 1 mark)
Flagella/Flagellum
(b) Paramecium
Cilia
( 1 mark)