KNEC KCSE BIOLOGY TOPICAL QUESTIONS AND ANSWERS

A group of students set up an experiment to investigate a certain physiological process. The set up was as shown in the diagram below.

3/11/2021

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A group of students set up an experiment to investigate a certain physiological process. The set up
was as shown in the diagram below.

(a) What physiological process was being investigated? (1mk)

Osmosis

(b) (i) State two major observation that was made after some time. (2mks)

Distilled in the Irish potato would reduce in level; (1mk)
Level of concentrated salt solution would increase in the Petri dish(2mks)

(ii) Account for the above observation in b (i) above. (4mks)

Concentrated salt solution in the Petri-dish has higher osmotic pressure than the cells of the Irish potato; these cells lost water to the salt solution by osmosis; these cells become more concentrated and drew water from the neighbouring cells; this process continued until the cells in contact with water in the potato drew it up. (4mks)

(c) State the significance of the biological process involved in the experiment. (1mk)

Support in herbaceous plants
Absorption of water
Opening and closing of stomata
Movement and water between plants
Feeding in sectivorous plants
Folding of leaves of mimosa pudica when touched

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Why is osmosis regarded as a special case of diffusion, List down two importance of active transport in animals

30/10/2021

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(a) Why is osmosis regarded as a special case of diffusion (1mk)

Involves the movement of water molecules from a region where they are highly concentrated to a region where they are lowly concentrated through a semi-permeable membrane.

(b) List down two importance of active transport in animals (2mks)

Reabsorption of sugars and some salts by the kidney;
Absorption of digested food from alimentary canal of animals into the blood stream;
Excretion of waste products from body cells;
Accumulation of substances into the body to affect osmotic imbalance in acid and saline environment.

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K.C.S.E Biology Q & A - MODEL 1995PP1QN11

24/5/2020

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K.C.S.E Biology Q & A - MODEL 1995PP1QN11

The diagram below represents a transverse section of a young stem

(a)Name the parts labeled A and B (2 mks)
(b)State the functions of the parts labeled C, D and E (4 mks)
(c)List three differences between the section shown above and one that would be obtained from the root of the same plant

(3 mks)

KNEC ANSWERS

(a)
- A – Epidermis
- B – Pith
(b)
- C – Transport manufactured food / translation; Rej. Digested food
- D – Produces new cells/ divides to give new cells. Accept secondary Thickening/ growth/ produces phloem & xylem.
- E- transport minerals salts/ minerals/ salts alone
(c)
- Xylem in central/ Star shaped
- Phloem in arms of xylem
- Root hairs present in root / has pilferous layer
- No pith in root

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Biology Questions and Answers

A group of students set up an experiment to investigate a certain physiological process. The set up was as shown in the diagram below.

A group of students set up an experiment to investigate a certain physiological process. The set up
was as shown in the diagram below.

(a) What physiological process was being investigated? (1mk)

(b) (i) State two major observation that was made after some time. (2mks)

(ii) Account for the above observation in b (i) above. (4mks)

(c) State the significance of the biological process involved in the experiment. (1mk)

Why is osmosis regarded as a special case of diffusion, List down two importance of active transport in animals

(a) Why is osmosis regarded as a special case of diffusion (1mk)

(b) List down two importance of active transport in animals (2mks)

K.C.S.E Biology Q & A - MODEL 1995PP1QN11

The diagram below represents a transverse section of a young stem

TOPICS

Form 2

Form 3

Form 4

Archives

Categories

Biology Questions and Answers

A group of students set up an experiment to investigate a certain physiological process. The set up was as shown in the diagram below.

​A group of students set up an experiment to investigate a certain physiological process. The set up was as shown in the diagram below.

​(a) What physiological process was being investigated? (1mk)

​(b) (i) State two major observation that was made after some time. (2mks)

​(ii) Account for the above observation in b (i) above. (4mks)

​(c) State the significance of the biological process involved in the experiment. (1mk)

Why is osmosis regarded as a special case of diffusion, List down two importance of active transport in animals

​(a) Why is osmosis regarded as a special case of diffusion (1mk)

​(b) List down two importance of active transport in animals (2mks)

K.C.S.E Biology Q & A - MODEL 1995PP1QN11

The diagram below represents a transverse section of a young stem

TOPICS

Form 2

Form 3

Form 4

Archives

Categories

A group of students set up an experiment to investigate a certain physiological process. The set up
was as shown in the diagram below.

(a) What physiological process was being investigated? (1mk)

(b) (i) State two major observation that was made after some time. (2mks)

(ii) Account for the above observation in b (i) above. (4mks)

(c) State the significance of the biological process involved in the experiment. (1mk)

(a) Why is osmosis regarded as a special case of diffusion (1mk)

(b) List down two importance of active transport in animals (2mks)