Form 3 Biology Exams and Marking Schemes Free

Name:……………………………………………………………………………..Admission No. ………………

School:…………………………………………………….Signature…………………… Date: ………………..

231/3

PAPER 3

BIOLOGY PRACTICAL

TIME: 1 ¾ HOURS

JOINt EXAMS

Kenya Certificate of Secondary Education (K.C.S.E)

INSTRUCTIONS TO CANDIDATES:-

Answer all the questions
Write your name, admission number and school in the spaces provided above.
Sign and write the date of examinationin the spaces provided above.
You are required to spend the first 15 minutes of 1 ¾ hours allowed for this paper reading the whole paper carefully before commencing your work.
Answers must be written in the spaces provided in the question paper.
Additional pages must not be inserted

FOR EXAMINER’S USE ONLY:

Question	Maximum score	Candidate’s score
1	13
2	8
3	19
TOTAL	40

This paper consists of 7 printed pages. Candidates should check to ascertain that all pages are printed as indicated and that no questions are missing.

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1 Study the photographs below and answer the questions that follow:

PHOTOGRAPH J PHOTOGRAPH K

a)Photograph K illustrates the observations made two weeks after the plant was trimmed.

(i)Name the phenomenon that was experienced by the plant before it was trimmed (1mk)

(ii) Account for the observation made in the shoot after the practice (2mks)

(iii) Give one application of the practice in agriculture (1mks)

b) In photograph J

(i) Name the part labeledA (1mk)

(ii) State one functions of part B (1mk)

c) The photograph below shows the arrangements of different type of cells and tissues in a certain living organism. Study it and answer the questions that follow.

i) From what part of the plant was the photograph obtained. (1mk)

ii) Name the parts Labeled. R (1mk)

d) i) State the function of the part labeled Q. (1mk)

ii) State one adaptation of structure Q to its function. (1mk)

e) State one environmental factor which regulate the function of the part labeled P. (1mk)

f) Measure the length of one cell of region labeled Q on the photomicrograph whose magnification is X5000.What is the actual length of the cell in micrometer? Show yourworking. (2marks)

Study the kidney diagrams below

a)i) Name the parts labeled A in figure 1

(1mk)

A ………………………………………………

ii) Name the processes that take place in the parts labeled (1mk)

V ………………………………………………

b) State two adaptations of the part labeled W (2mks)

c) On the diagram name the part where counter current flow occurs (1mk)

d) State one homeostatic function of the organ in the diagram above (1mks)

e) Explain what will happen to the process of urine formation in absence of vasopressin (A.D.H)

hormone. (2mks)

You are provided with specimen Y, 0.01% DCPIP and 0.1% Ascorbic Acid.

Examine specimen Y.

a).i) What part of plant is specimen Y? (1mk)

ii) Give a reason for your answer for (a) (i) above. (1mk)

b) Cut a transverse section through specimen Y (3mks)

Draw and label one of the cut surface

c)i)To 1cm³of DCPIP in a test-tube add 0.1% solution of ascorbic acid drop wise until the colour of DCPIP disappears. Shake the test tube after addition of each drop. Record the number of drops used (1mk)

…………………………

Squeeze the juice from one half of specimen Y in a l00mI beaker. Add l0mI of distilled water. Filter it in 50ml measuring cylinder provided.

To another 1cm³ of DCPIP in a test tube, add the juice from specimen Y drop by drop. Shake the test tube after the addition of each drop until the colour of DCPIP disappears. Record the number of drops used (1mk)

………………………………………………

iii) From the results obtained in (c)(i) and (ii) above, calculate the % ascorbic acid in the juice obtained from specimen Y. show your working. (2mks)

Below are photographs labelled B and C of organs obtained from different animals . The organs perform similar functions. Examine them and answer the questions that follow.

B C

(i) Name the organ C (1mk)

(ii) Give one adaptation of the part marked B1 (1mk)

(b) State one common function performed by the organ stated in a (i) above. (1mk)

B1………………………………….

B2…………………………………

(d) (i)Identify the part labelled K2 in photograph C (1mk )

(ii) Using observable features, state how the parts labelled K1 and K3 are adapted to their functions. (4mks)

_______________________________________________________________________________________

JOINT EXAMINATIONS

231/3

MARKING SCHEME

1 (a) (i) Apical dominance; Rej wrong spelling

(ii) Removal of the apical shoot/shoot apex removes auxines; allowing for the development of lateral buds; leading to formation of lateral shoots/branches

shown;

(iii) pruning of crops like tea and coffee leading to increased yields;

Pruning of trees to increase wood;

Trimming of fences to attain the desired shape;

(b) (i) Hypocotyl;Rej wrong spelling

(ii) Stores nutrients/food for germinating seed;

Manufactures food to seedling

Protects the embryo/plumule and radical;Any one

(ii) R spongy layer /cells/mesophyll cells;

(d) (i) Site for photosynthesis;

(ii) Has numerous chloroplasts(which contain chlorophyll) for photosynthesis;

Closely packed /vertical arrangement or maximum absorption of light;

Positioned on the upper surface to absorb maximum light;

(e) Light;

Temperature;

Availability of water

(f) Length =l.5cm± 0.1

Actual length=

=15000÷X5000

=3m;/3micrometers

(a) (i) Renal vein;

(ii) Ultra filtration;

(b) Has numerous mitochondria to provide energy for active transport;

Has microvilli in the lining to increase surface area for reabsorption of substances;

Highly vascularised for transport of reabsorbed substances; Has thin epithelium for rapid diffusion of substances;

(d) Osmoregulation;/Regulation of PH;

(e) The distal convoluted tubules and collecting duct wilt be less permeable to water; therefore less reabsorption of water; leading to production of large volume of urine that is dilute;

(a) (i) Fruit;

(ii) Has two scars;

(b) Drawing 1

Labeling 1 (Any correct 2)

Magnification 1

(ii) 6drops;

(iii) If 2drops=0.1%

6drops =2×0.¹/₆

=0.03%

(d) (i) Fish Gill

(ii) Has rings of cartilage to prevent collapsing

Has mucus to trap foreign particles.

(b) Gaseous exchange

-Excretion of carbon(iv) oxide

B2 – Lung (rej. Lungs)

(d) (i)

K2 – Gill bar

Complete answers include the “gill”

(ii)K1 – Gill rakers are pointed ; for trapping solid particles / prevent solid particles from reaching gill filaments and causing damage.

K3 – Numerous gill filaments; to increase the surface area for gaseous exchange.

_____________________________________________________________________________________________

BIOLOGY FORM 3 P2 TERM 3 MARKINGSCHEME

(a) Guttation: release of waterin droplets by plants through hydathodes;

Transpirations: loss of water in form of vapour through stomata into the

atmosphere.(2mks)

(b) – Through transpiration minerals ions and water are transported in plants.

– cools the plant

– removes excess water especially in aquatic plants

– responsible for turgor in plants. (any 3) (3mks)

(c )

Arteries

Veins

1. Narrow lumen

2. No valves except at the base of major arteries leaving the heart.

3. Thick muscular walls with more elastic fibres

– Wider lumen

– Have valves at intervals

– Walls thin less muscular with less elastic fibres

(a) gill acc fish gill rej gill fish

(b) Gill arch/bar; Gill rakers; gill filament. (3mks on diagram)

– thin epithelium for respiratory gases to take a short distance bydiffusion.

– network of blood capillaries to transport respiratory gases.

-Moist for dissolution of respiratory gases. (4mks)

(a) (i) B – Seta

D – Rhizoid

(ii) A – produce spores

C _ photosynthesize

(b) (i) Arthropoda; sp

(ii) Segmented body;

Jointed appendages rej Limbs /legs

Presence of an Exoskeleton;

a) Photosynthesis (1mk)
b) -Light (energy);

-Chlorophyll; (2mks)

c) i. Oxygen – used in respiration;

– released into the atmosphere (2mks)

ii) Glucose – Used in respiration;

-converted to starch for storage;

-Used in formation of cellulose/constituent of cell sap; (3mks)

a) Reflects light through condenser to the stage;
b) Moves high power objective lens for longer distance; thus breaking the glass slide/ destroying the lens;
c) i) (4mks)

Electron

Light

1. higher magnification

2. high resolving power

3. uses a beam of electrons to illuminate the specimen

4. views dead specimen

5. uses electromagnetic lenses

Lower magnification

Lower resolving power

Uses light to illuminate the specimen

Views both live and dead specimens

Uses glass lenses

ii) To make the structures clearer/distinct

i) 0 – 2 months

No change in population /population is constant;

Mice still maturing /have not given birth;

ii) 2 to 6 months

gradual /slow population growth ; few mice have reached sexual maturity;

iii. 6 to 10 months

rapid /faster rate of population growth;

many mice sexually mature;

iv) 10 to 12 months

population decline/decrease;

competition is high /food limiting/space is limiting

accumulation of toxic waste/disease outbreak/ death rate is higher than birth rate.

c) (i) 6 and 8;

(ii)

=125 – 130 mice per month

d) population would increase
e) food, space/cage size; water; (mark first 2)
– Pituitary gland;

Secrets follicle simulating hormone;
S.H causes graaffian follicle to develop in ovary;
It also stimulate tissue of ovary;
To secrete oestrogen;
Oestrogen causes repair /healing of uterine wall;
Oestrogen stimulates pituitary gland
To produce luteinizing hormone;
H causes ovulation
It also causes graffian follicle to change into corpus luteum;
H stimulates corpus /uteum;
To secrete progesterone;
Progesterone causes proliferation of uterine wall;
In preparation for implantation
Progresterone /oestrogen inhibits the production of S.H
Thus no more follicles develop ; and oestrogen reduces .
In the next two weeks progesterone level rises ;
And inhibits production of L.H’ the corpus luteum stops secretion of progrestrone;
And menstruation occur when level of progesterone drops ; (total 21 max 20)

a) Diffusion of CO2; and oxygen ; through stomata. Lenticels

deposition /some wastes are stored in tissues in non-toxic form;
some of these tissues/organs drop off from plants
some wastes cleansed by transpiration
other released by guttation
other released by exudation (total 8 max 4)

b) -When body temperature is lowered below normal;

– blood vessels in skin constrict;

-blood is diverted to a shunt system;

– Less blood flows to skin hence less heat lost;

when body temperature is raised above normal;
blood vessels in skin dilates;
more blood flows to the skin;
more heat lost by convection/ raditation;

erector Pili muscles

when temperature of body is lowered below normal erector pili muscles contract; hair stands erect; more air is trapped ; air is a bad conductor ; and insulates the body against heat loss
when body temperature is raised above normal erector pili muscles relax; hair lies on the skin; less air is trapped; more heat is lost;

sweat glands

when body temperature is lowered below normal less fluids are absorbed by sweat glands / less sweating; less vaporization of water;

when body temperature is raised above normal sweat glands are more stimulated / more sweat is produced ; water in the sweat evaporates using latent heat of vapourisation ; cooling body. (total 22 max 16)

_________________________________________________________________________________________________

NAME: ……………………………………………………ADM NO: ……………………………….

CLASS…………………………………………………..DATE: ……………………..……………..

231/1

BIOLOGY

FORM THREE

TIME: 2 HOURS

JOINT EXAMINATION

INSTRUCTIONS TO CANDIDATES:

This paper consists of thirtysix (36)Questions
Write your name andADM Number and class in the spaces provided above.
Answer all the questions
All answers must be written in the spaces provided in this booklet.
Write the date of examination in the space provided above.
Additional pages must not be inserted

EXAMINER’S USE ONLY

Question	Maximum score	Candidates score
1-36	80

This paper consists of 9 printed pages. Candidates should check to ascertain that all papers are printed as indicated and that no questions are missing

State three ways in which proteins are important to plant. (3marks)

………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

The diagram below represents a cell organelle.

(a) Identify the organelle. (1 mark)

……………………………………………………………………………………………….

(b) Name the part labeledB. (1 mark)

………………………………………………………………………………………………..

……………………………………………………………………………………………………..

Define binominal nomenclature. (1marks)

……………………………………………………………………………………………………………………………………………………………………………………………………………………

Name any two problems that animal species overcome by their dispersion. (2marks)

…………………………………………………………………………………………………………………………………………………………………………………………………………………….

Explain why tropical forests do not have undergrowth (2marks)

How is blood pressure generated and maintained in a vein? (2marks)

Explain the function of catalase enzyme. (2marks)

(a) State the important of cross-pollination to flowering plants. (1mark)

(b) How is self-pollination a disadvantage to flowering plants? (1mark)

What is the role of light energy in autotrophic nutrition in spermatophyte? (2marks)

How is fur important to desert animal, other than in the regulation of their body temperature?

(1mark)

…………………………………………………………………………………………………………

What are the functions of the followingantibodies produced by the white blood cells. (3marks)

Agglutinins……………………………………………………………………………………………Opsonins………………………………………………………………………………………………

Lysins…………………………………………………………………………………………………

Explain two adaptations of cardiac muscles to their function. (2marks)

……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………….

A form one student trying to estimate the size of onion cells observed the following on the microscope’s field of view.

(a) Define the term resolving power. (1mark)

…………………………………………………………………………………………………….

(b) If the student counted 20 cells across the field of view, calculate the size of one cell in micrometers. (3marks)

What is tidal volume in ventilation in man? ` (1mark)

Define peristalsis and state its importance in the nutrition of mammals. (2marks)

………………………………………………………………………………………………………………………………………………………………………………………………………………….

The diagram below shows part of plant tissue.

Name cell labeled X and part labeled W. (2marks)

X……………………………………………………….

W………………………………………………………

Explain why the liver is part of the digestive system. (2marks)

…………………………………………………………………………………………………………………………………………………………………………………………………………………..

State the importance of cytoplasmic filaments in sieve tube elements. (1mark)

…………………………………………………………………………………………………………

State any two characteristics of populations. (2marks)

Describe any two functions of mitosis. (2marks)

The diagram below shows the exchange of gases in alveolus.

State how the alveoli are adapted to their function. (3marks)

………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

(b) Name the cell labeledA. (1mark)

……………………………………………………………………………………………………

What are the external conditions needed, by root hair cells, for the uptake of mineral salts ions from the soil? (2marks)

……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………..

The diagram below represents a pyramid of biomass derived from a certain ecosystem

(a) Suggest the type of ecosystem from which the pyramid was derived (1mark)

………………………………………………………………………………………

(b)State the significance of short food chains in an ecosystem (1mark)

……………………………………………………………………………………………………

Suggest two reasons for the appearance of glucose in the urine of a man. (2marks)

(a) State the source Carbon (IV) oxide in aquatic ecosystems. (2marks)

……………………………………………………………………………………………………………………………………………..

(b) State the importance of Carbon (IV) oxide to aquatic ecosystems. (2marks)

………………………………………………………………………………………………………………………………………………………………………………………………….. ………………

The set up below shows apparatus to demonstrate a certain biological process

(a) What biological process was being investigated in the experiment (1mark)

…………………………………………………………………………………………………….

(b)Write down a word equation that represents the reaction above (1mark)

……………………………………………………………………………………………………..

What is the homeostatic importance of cuticles of leaves? (2marks)

Outline two functions of parenchyma cells in herbaceous plants. (2 marks)

State adaptations of respiratory surfaces. (2marks)

The diagrams below show a pair of homologous chromosomes. Study them and answer the questions that follow.

(i)State the phenomenon shown above (1mark)

……………………………………………………………………………………………………

(ii) What is the genetic significance of the phenomenon above? (2marks)

…………………………………………………………………………………………………………………………………………………………………………………………………………

Account for the thick wall and narrow lumen of an artery. (2marks)

How do pathogens that enter the body through the respiratory tract in man prevented from causing diseases? (1mark)

Where does the detoxification of ammonia take place in mammals? (1mark)

Name the processes that take place in the grana of chloroplast. (2marks)

………………………………………………………………………………………………………………………………………………………………………………………………………………………….

The experiment illustrated below was set up to investigate a certain physiological process using a raw tuber

(a) Suggest a possible physiological process that was being investigated (1mark)

………………………………………………………………………………………………

(b) Explain the results obtained in the above experiment after a few hours (2marks)

………………………………………………………………………………………………..

………………………………………………………………………………………………….

Name the causative organism of the following diseases

(i) Malaria (1mark)

……………………………………………………………………………………………

(ii) Bilharzia (1mark)

………………………………………………………………………………………………

Form 3 Biology Exams and Marking Schemes Free

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