SUKELLEMO JOINT MOCK
Kenya Certificate of Secondary Education
BIOLOGY PAPER 3
(Practical)
1¾ HOURS
Instructions to Candidates
- Answer all the questions in the spaces provided.
- Spend the first 15 minutes of the 1¾ hours to read through the paper carefully before commencing your work.
- One may be penalized for recording irrelevant information and for incorrect spelling, particularly of technical terms.
- You are provided with two pieces of plant material labelled specimen D. using a scalpel cut a longitudinal section half way through the middle of each piece as shown in the diagram below.
- Place one piece in solution labelled ?1 and the other piece in the solution labelled ?2. Allow the set up to stand for 30 minutes.
- Record your observation (2 marks)
L1
L2
- Record your observation (2 marks)
- Examine the pieces.
- Record other observations besides those made in (a) (i) above. (3marks)
- Account for the observation in (a) (i) above. (5 marks)
- Account for the observation in (b) (i) above. (3marks)
- Place one piece in solution labelled ?1 and the other piece in the solution labelled ?2. Allow the set up to stand for 30 minutes.
- You are provided with photographs of specimen M and N. Examine them.
- Identify the bones. (2marks)
M
N - Name the parts labeled X and Y. (2marks)
X
Y - State three significance of the part labelled Y. (3 marks)
Y- .
- .
- .
- Calculate the actual size of specimen labelled M. (Show your working). (3marks)
- Name the part of the mammalian body from where the specimens were obtained. (1mark)
- State with reasons the type of joint formed at the proximal and distal end of M (4marks)
Proximal end
Reason
Distal end
Reason
- Identify the bones. (2marks)
-
- The photographs below are for specimen labelled P,Q and R.
- State with a reason the class to which specimens P belongs. (3 marks)
P
Reason - What type of germination is exhibited by Q? (2marks)
Q
Give a reason for your answer. - Name the parts labelled U and V on the photographs above. (2marks)
U
V
- State with a reason the class to which specimens P belongs. (3 marks)
- The diagrams below shows the photographs of specimens A and B
- Using observable features only, state the class to which the specimen in photographs A belongs. (1mark)
- Give a reason for your answer. (1mark)
- State the habitat in which the specimen in photograph B is found. (1mark)
- Identify the stage of development of the specimen in photograph B. (1mark)
- Give a reason for your answer in (b) (iv) above. (1mark)
- The photographs below are for specimen labelled P,Q and R.
CONFIDENTIAL
- 2 Pieces of Tradescantia zebrina stem (4 cm each) – labelled D
- 20 ml of Solution labelled L_1 – distilled water in 50 ml beaker
- 20 ml of Solution labelled L_2 - 2 % salt solution in 50 ml beaker.
- Scalpel blade.
MARKING SCHEME
- You are provided with two pieces of plant material labelled specimen D. using a scalpel cut a longitudinal section half way through the middle of each piece as shown in the diagram below.
- Place one piece in solution labelled ?1 and the other piece in the solution labelled ?2. Allow the set up to stand for 30 minutes.
- Record your observation (2 marks)
L1 - The stem is hard/firm/stiff;
L2 - The stem is soft;
- Record your observation (2 marks)
- Examine the pieces.
- Record other observations besides those made in (a) (i) above. (3marks)
- L1 The slit opens wider; and bends outwards towards the epidermis/cuticle;
- L2 The slits remain close together;
- Account for the observation in (a) (i) above. (5 marks)
- Solution L1 is hypotonic to the cell sap; water moved into the stem cells by osmosis; the cells of the stem became turgid;
- Solution L2 is hypertonic to the cell sap; water moved out of the cells by osmosis making the cells of the stem become plasmolysed and the tissue soft;
- Account for the observation in (b) (i) above. (3marks)
- L1 The cells in the inner surface/cut surface enlarge more because they took in more water by osmosis; than the outer cells which have cuticle; in ?? the cells in the cut surface lost more water by osmosis than the outer cells with cuticle;
- L1 The cells in the inner surface/cut surface enlarge more because they took in more water by osmosis; than the outer cells which have cuticle; in ?? the cells in the cut surface lost more water by osmosis than the outer cells with cuticle;
- Record other observations besides those made in (a) (i) above. (3marks)
- Place one piece in solution labelled ?1 and the other piece in the solution labelled ?2. Allow the set up to stand for 30 minutes.
- You are provided with photographs of specimen M and N. Examine them.
- Identify the bones. (2marks)
- M Humerus;
- N Ulna & radius;
- Name the parts labeled X and Y. (2marks)
- X Olecranon process;
- Y Sigmoid notch;
- State three significance of the part labelled Y. (3 marks)
Y- Attachment of muscles/tendons;
- Formation of hinge joint ;( with adjacent bone)
- prevents overstretching of the forearm backwards
- Calculate the actual size of specimen labelled M. (Show your working). (3marks)
- Actual length = 22.6 ± 0.1cm
- Drawing length = 11.3 ± 0.1cm
- Magnification=Drawing length/actual length=11.3/22.6;=11cm/actual =22cm;
- Name the part of the mammalian body from where the specimens were obtained. (1mark)
- Forelimb/arm/legs; acc humerus –upper arm; Ulna and radius lower arm;
- Forelimb/arm/legs; acc humerus –upper arm; Ulna and radius lower arm;
- State with reasons the type of joint formed at the proximal and distal end of M (4marks)
Proximal end - Ball and socket;
Reason - Head shaped like a ball/rounded head/round head/Allows movement in all planes/360°;
Distal end - Hinge joint;
Reason - Allows movement in only one plane/presence of a groove/presence of condyles/troches which articulates with the sigmoid notch;
- Identify the bones. (2marks)
-
- The photographs below are for specimen labelled P,Q and R.
- State with a reason the class to which specimens P belongs. (3 marks)
P Monocotyledonae;
Reasons Leaves with parallel veins; presence of leaf sheath; - What type of germination is exhibited by Q? (2marks)
Q Epigeal;
Give a reason for your answer.
The cotyledons carried above the soil surface; - Name the parts labelled U and V on the photographs above. (2marks)
U Hypocotyl;
V cotyledon;
- State with a reason the class to which specimens P belongs. (3 marks)
- The diagrams below shows the photographs of specimens A and B
- Using observable features only, state the class to which the specimen in photographs A belongs. (1mark)
- Insecta;
- Give a reason for your answer. (1mark)
- Presence of six legs/ three body parts/ one pair of antenna;
- State the habitat in which the specimen in photograph B is found. (1mark)
- Dead decaying organic matter;
- Dead decaying organic matter;
- Identify the stage of development of the specimen in photograph B. (1mark)
- Larva;
- Larva;
- Give a reason for your answer in (b) (iv) above. (1mark)
- Absence of legs/wings/presence of fleshy protuberances/presence of a hook-like tooth
- Absence of legs/wings/presence of fleshy protuberances/presence of a hook-like tooth
- Using observable features only, state the class to which the specimen in photographs A belongs. (1mark)
- The photographs below are for specimen labelled P,Q and R.
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