KNEC KCSE BIOLOGY TOPICAL QUESTIONS AND ANSWERS

State four reasons why water is significant in seed germination.

25/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2011PP1QN29

State four reasons why water is significant in seed germination.

ANSWER

Activate enzymes; provides a medium for enzymatic activities to break down stored food to soluble form; Hydrolyses, dissolves food materials; is a medium of transportation of dissolve food substances to growing regions of radicle and plumule;
Softens seed coat to facilitate emergence of radicle;

Comments

State two ways by which auxins regulate growth in seedlings.

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN28

State two ways by which auxins regulate growth in seedlings.

ANSWERS

Accelerates growth of shoots;
Can inhibit growth of roots;

Comments

What is a tropic response?

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN28

What is a tropic response?

ANSWERS

It is a growth movement in plants in response to a unidirectional stimulus;

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K.C.S.E Biology Q & A - MODEL 2011PP1QN27

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN27

The diagram below represents features of a joint in a mammal.

(a)Name the part labelled A.
(b) State the function of the part labelled B.

ANSWERS

(a) Ligament;
(b) Secretes synovial fluid; contains/holds the synovial fluid in place;

Comments

Name the gamete cells that are produced by the ovaries.

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN26

Name the gamete cells that are produced by the ovaries.

ANSWERS

egg/ovum/ova;

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K.C.S.E Biology Q & A - MODEL 2011PP1QN25

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN25

State one economic importance of each of the following plant excretory products.
(a) Tannin.
(b) Quinine.
(c) Caffeine.

ANSWERS

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What would be the expected results from a test cross?

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN24

What would be the expected results from a test cross?

ANSWERS

Either all offspring show the dominant characteristics;
or half offspring show the recessive while the other half show the dominant characteristics;

Comments

K.C.S.E Biology Q & A - MODEL 2011PP1QN24

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN24

Differentiate between the following terms:
(i)dominant gene and recessive gene:
(ii) continuous variation and discontinuous variation.

ANSWERS

(i) Dominant gene expresses itself phenotypically in both its homozygous and heterozygous states while recessive gene can only express itself phenotypically in the homozygous state;
(ii) Continuous variation is a characteristic for which there is a continuum or range while discontinuous variation is a characteristic for which there are discrete categories or units;

Comments

K.C.S.E Biology Q & A - MODEL 2011PP1QN23

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN23

The diagram below represents a transverse section of an ovary from a certain flower.

a) (i)Name the structure labelled W.
(ii)Name the type of placentation illustrated in this diagram.
(b) Give an example of a plant whose flowers have the type of placentation named in (a)(ìi) above.

ANSWERS

(a) (i) Ovule;
(ii) Axile placentation;
(b) Orange or any correctly named citrus plant;

Comments

State the difference in content of oxygen and carbon (IV) oxide in the air that enters and leaves the human lungs.

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN22

State the difference in content of oxygen and carbon (IV) oxide in the air that enters and leaves the human lungs.

answers

Air that enters lungs has a higher content of oxygen than air that leaves the lungs;
Air that enters the lungs has lower content of carbon (IV) oxide than air that leaves the lungs;

Comments

State two limitations of fossils as an evidence of evolution.

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN21

State two limitations of fossils as an evidence of evolution.

answers

Missing links;
Distortion of parts during sedimentation/earthquakes/putrefìcation;
Destruction of fossils by geological activities/faulting/folding;

Comments

What is meant by convergent evolution?

25/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2011PP1QN21

What is meant by convergent evolution?

answer

Where different structures evolve to perform the same function (e.g. wings of insects and birds are different in structure but are used for flying);

Comments

K.C.S.E Biology Q & A - MODEL 2011PP1QN20

25/6/2020

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K.C.S.E Biology Q & A - MODEL 2011PP1QN20

The number of stomata on the lower and upper surfaces of two leaves from plant species X and Y were counted under the field of view of a light microscope. The results were as shown in the table below.