KNEC KCSE BIOLOGY TOPICAL QUESTIONS AND ANSWERS

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;

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K.C.S.E Biology Q & A - MODEL 2010PP2QN01

24/6/2020

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K.C.S.E Biology Q & A - MODEL 2010PP2QN01

In an experiment, disinfected soaked bean seeds were put in a vacuum flask which was then fitted with a thermometer as shown in the diagram below.

The temperature readings were taken every morning for three consecutive days.
(a) Which process was being investigated?
(b) (i) What were the expected results?
(ii) Account for the answer in (b)(i) above,
(c) Why were the seeds disinfected?
(d) Why was a vacuum flask used in the set-up?
(e) How would a control for this experiment be set?

answers

(a) Respiration;
(b) (i) Increase/rise in thermometer reading/temperature;
(ii) Carbohydrates/starch/glucose in germinating seeds is broken down/oxidised to get energy; some of the energy is released as heat; (which increases temperature reading).
(c) To kill bacteria/fungi/microorganisms; that would cause decay/decomposition/respiration of the beans;
(d) To conserve heat/prevent heat loss to surroundings;
(e) Use similar set-up but with dead and disinfected beans seeds/ use dead disinfected bean seeds/use dry bean seeds;

Comments

What is meant by the term apical dominance?

24/6/2020

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K.C.S.E Biology Q & A - MODEL 2010PP1QN30

What is meant by the term apical dominance?

answer

The inhibition of growth of lateral buds;
By auxins; produced by the growing apical bud;

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K.C.S.E Biology Q & A - MODEL 2009PP1QN11

23/6/2020

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K.C.S.E Biology Q & A - MODEL 2009PP1QN11

In an experiment the shoot tip of a young tomato plant was decapitated as shown in the diagram below

(a) State the expected results after 2 weeks
(b) Give a reason for your answer in (a) above

ANSWERS

(a) auxiliary/ lateral buds spront/ bronches will be formed
(b) Decapitation removes the hormone/ ouxins /IAA which is produced in the terminal bud/ the stem tip; abseul/ removal of the hormone/ auxins/ IAA promote branch/ development of auxiliary lateral buds.

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K.C.S.E Biology Q & A - MODEL 2009PP1QN04

23/6/2020

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K.C.S.E Biology Q & A - MODEL 2009PP1QN04

The diagram below represents a stage during germination of a seed

(i) Name the type of germination illustrated in the diagram
(ii) State the role of the part labeled x during germination of the seed

ANSWERS

(i) Epigeal
(ii) Protection of the delicate plumule; pulls the cotyledons above the ground

Comments

The state during which a seed cannot germinate even when conditions for Germination are suitable is called

23/6/2020

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K.C.S.E Biology Q & A - MODEL 2009PP1QN04

The state during which a seed cannot germinate even when conditions for Germination are suitable is called

ANSWER

(seed) dormancy

Comments

Name a growth inhibitor in seeds

22/6/2020

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K.C.S.E Biology Q & A - MODEL 2008PP1QN21

Name a growth inhibitor in seeds

ANSWER

Absisicic acid

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What is seed dormancy

22/6/2020

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K.C.S.E Biology Q & A - MODEL 2008PP1QN21

What is seed dormancy

ANSWER

State during which a seed cannot germinate/ state of rest before seed germination;

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K.C.S.E Biology Q & A - MODEL 2008PP1QN17

22/6/2020

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K.C.S.E Biology Q & A - MODEL 2008PP1QN17

Account for the following phases of a sigmoid curve of a growth of an organism
(a) Lag phase
(b) Plateau phase

ANSWERS

(a) Few dividing cells/ cells not adjusted to surrounding environment
(b) Most cells fully differentiated/ rate of cell division equals rate of cells dying

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