BIOLOGY
PAPER 3
INSTRUCTIONS TO CANDIDATES
- Write your name and index number in the spaces provided above.
- Sign and write the date of examination in the spaces provided above.
- You are required to spend the first 15 minutes of the 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.
For Examiner’s Use only:-
Question |
Maximum Score |
Candidate’s Score |
1 |
14 |
|
2 |
13 |
|
3 |
13 |
|
TOTAL |
40 |
QUESTIONS
- Below are photographs of two specimens, J and Both of them belong to the same phylum and class. Observe them carefully before you answer the questions that follow.
- Name the class to which J and K belong and support your answer with two reasons.
Class ………………………………………………………………………………….1mk
Reasons 2mks- ……………………………………………………………………………
- ……………………………………………………………………………
- Suggest why the circulatory fluid in J and K has no haemoglobin. 2mks
- Observe their wings and suggest the type of evolution that could have taken place to give rise to J and K, and then give a reason for your answer.
Type of evolution …………………………………………………………………1mk
Reason ………………………………………………………………………………………………………………………………………………2mks - Below is a diagram showing the life cycle of specimen J.
- Identify the stage labeled D. ……………………………………………………..1mk
- Name the hormone responsible for the change from D to A. 1mk
- Explain the differences in the change from C2 to C3 and from C3 to D. 4mks
- Name the class to which J and K belong and support your answer with two reasons.
Q2. Study the organisms below and answer questions in spaces provided .
- Complete and use the key below to identify the organism. 2mks
1a. Organism with endoskeleton ………………………………………… go to 2
1b. ______________________ ………………………………………………… go to 32a. Has scales on the body………………………………………………… go to 4
2b. Has no scales on the body…………………………………… mammalian.3a. Has cephalothorax ………………………………………………… Arachnida.
3b. Has no cephalothorax………………………………………………go to 54a. __________________________________............................... pisces
4b. Has no fins …………………………………………………….. Go to 75a. Has three pairs of legs …………………………………………… Insects.
5b. Has more than three pairs of legs …………………………… go to 66a. Two pairs of legs per segment ……………………………………Diplopoda
6b. One pair of legs per segment………………………………………chilopoda.7a. Has feathers ……………………………………………………………… Aves
7b. Has no feathers …………………………………………………………go to 88a. Has a tail…………………………………………………………………Reptilia
8b. Has no tail……………………………………………………………Amphibia. - Identify the organisms above using the completed key above. 6mks
Specimen Steps followed Identity A B C D E F -
Name the phylum in which specimens C, E and F belong to ……………………………………………..1mk
-
Give three reasons for your answer in (c). 3mks
-
Name one feature that is common in organisms B, D and E. 1mk
Q3.You are provided with a specimen labeled T which is a fruit. Use it to answer the questions that follow.
- Make a transverse section of the specimen T. Draw and label at least 3 parts. 6mks
- With reasons, state the identity of fruit
Type of fruit………………………………………………………………………..1mk
Reason …………………………………………………………………………………1mk - Suggest the possible agent of dispersal and give two reasons
Agent …………………………………………………………………………………1mk
Reason ………………………………………………………………………………………………………2mk - What is the placentation of T? …………………………………………………….1mk
- Specimen T was green in colour before it was treated with a plant hormone.
Suggest the plant hormone.………………………………………………………………………………………1mk
Marking Scheme
- Below are photographs of two specimens, J and K. Both of them belong to the same phylum and class. Observe them carefully before you answer the questions that follow.
- Name the class to which J and K belong and support your answer with two reasons.
Class Insecta; 1mk Rej. insect
Reasons 2mks
i). Six legs; three body parts; two antennae; two compound eyes; - Suggest why the circulatory fluid in J and K has no haemoglobin. 2mks
Haemoglobin used to transport oxygen/ carbon (IV) oxide in the body; oxygen is taken directly to tissues/ carbon (IV) oxide taken directly from tissues by tracheoles; - divergent evolution; 1mk
Reason one pair of wings in J reduced to halters/ are vestigial; but both are functional in K 2mks -
- pupa stage; 1mk
- Ecdysone; accept Moulting hormone 1mk
- 4mks
C2 to C3 – moulting hormone / Ecdysone induce moulting; but presence of juvenile hormone prevent formation of pupa;
C3 to D – moulting hormone / Ecdysone induce moulting; but abscence of juvenile hormone lead to formation of pupa;
- Name the class to which J and K belong and support your answer with two reasons.
-
- 1b – organism with exoskeleton
4a. – has fins -
Specimen Steps followed Identity A 1a, 3a Arachnida B 1a, 2a, 4a Pisces C 1b,3b, 5b, 6b Chilopoda D 1a, 2a, 4b, 7b, 8a Reptilian E 1a, 2a, 4b, 7a, Ave F 1b, 3b, 5a Insect -
Arthropoda
rej: Anthropoda or arthropoda -
They all have exoskeleton
They have segmented bodies
They all have jointed appendages/limbs -
Scales
- 1b – organism with exoskeleton
3.
-
5mks
Magnification between X1 and X5 - Type of fruit Berry 1mk
Reason has many seeds 1mkAgent Animal 1mk
Reason brightly coloured; scented; fleshy; large; first 2mk - Axile; 1mk
- Ethylene/ ethyne; 1mk
CONFIDENTIAL
Each candidate should have:
- One ripe banana
- Scalpel/blade
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