Past Question and Answers on Growth and development of Plants

 SSCE/WASSCE/GCE PAST QUESTIONS AND ANSWERS

OBJECTIVES

The process involved in positive phototrophic response of a shoot are as follows

i.        Lateral transfer of auxins away from a light source

ii.      Increase in concentration of auxins in the shaded side of shoot

iii.    Growth of shoot in the direction of light source

iv.    Increase in cell division on the shaded side of shoot

1.      Which of the following arrangements is the correct sequence of events?

A.    I, II, III, IV       C.  II, I, IV, III

B.     I, II, IV, III       D.  II, III, IV, I

2.      Fruit enlargement can be induced by spraying young ovary with

A. cytokinin, abscisic acid and ethylene

B. gibberellin, ethylene and abscisic acid

C. auxin, abscisic acid and ethylene

D. auxin, cytokinin and gibberellin

3.      The movement of the whole organism to an external stimulus termed

A. tropism            C. a nastic movement

B. a taxis          D. a phototropic movement

4.      A dwarf plant can be stimulated to grow to normal height by the application of

A. thyroxin              C. insulin

B. gibberellin           D. cytokinin

5.      The response shown by the tips of the root and shoot of a plant to the stimulus of gravity is

A. haptotropism              C. hydrotropism

B. phototropism              D. geotropism

6.      Secondary thickening in dicotyledonous stem is controlled by the

A. xylem               C. cambium

B. phloem             D. pericycle

7.      When a healthy shoot of a flowering plant is illuminated from one side, auxins, accumulate on the

A. non-illuminated side of the shoot

B. illuminated side of the shoot

C. upper side of the shoot

D. lower side of the shoot

8.      The substance that is responsible for optical dominance in plants is known as

A. gibberellin              C. auxin

B. tannin                      D. kinin

9.    Which of the following growth activities in plants is brought about by gibberellins?

A. Rapid cell division      

B. Tropic response

C. Cell elongation

D. Main cell elongation

10.    The response of plants to external stimuli in a non-directional manner is known as

A. Tactic movement       C. Geotropism

B. Phototropism       D. Nastic movement

11.    The most important hormone that induces the ripening of fruit is

A. Ethylene                       C. Gibberallin

B. Indole acetic acid          D. Cytokinin

12.    Auxins are produced in the

A. petiole of leaves

B. parenchyma of roots and shoots

C. epidermis of roots and shoots

D. apical regions of roots and shoots

13.    Which of the following is not true about auxins? They

A. are manufactured by plants

B. are used in the site of production

C. are normally present in minute quantities in the cells of plants

D. regulate growth rate of plants

14.    Which of these instruments can be used to perform an experiment on geotropism?

A. Potometer                    C. Klinostat

B. Cup anemometer         D. Kymograph

15.    A high concentration of auxin in the root will

A. inhibit growth

B. stimulate growth

C. not affect growth

D. cause the root to root

16.    Secondary growth is brought about by the activities of the

A. phellogen and phelloderm

B. phellogen and procambium

C. vascular cambium and phelloderm

D. vascular cambium and phellogen

17.    Growth in plants is promoted by

A. suberin        C. lactic acid

B. auxin          D. prolactin

18.    Cells in the cambial ring divide tangentially to produce

A. secondary xylem only

B. secondary phloem only

C. secondary xylem inside and secondary phloem outside

D. secondary xylem outside and secondary phloem inside

19.    The hormone involve in tropic movement in plant is

A. abscisic acid          C. cytokinin

B. auxin                     D. gibberellins

20.    After secondary growth in plants, the widest tissues is the

A. cambium            C. phellem

B. phelloderm        D. xylem

 

Answers

1. B	6. C	11. A	16. D
2. D	7. A	12. D	17. B
3. B	8. C	13. B	18. C
4. B	9. C	14. C	19. B
5. D	10. A	15. B	20. B

 

THEORY

1.      (SSCE, 1999 Q3) (a) Explain the following terms:

(i) Tropism      (ii) Nastic movement

(b) Describe briefly an experiment to demonstrate that growth hormones are produced at the apex of he coleoptile.

(c) State what happen to a seedling subjected to unilateral source of light and explain the mechanism involved.

Solution

(a) (i) , (ii) Refer to blog content

(b) when the tip of a coleoptile is cut off, the coleoptile stops increasing in length. When the tip is replaced growth resumes. If the excised tip is replaced on an agar block for a while and block alone is placed on the coleoptile stumps, the stump resumes normal growth, indicating that substance diffuse from the coleoptile tip downwards to cause growth in the shoot.

(c) Phototropism: when a seedling subjected to unidirectional source of light, the shoot bend towards the source of light.

The auxins (growth hormone) move from the lighted side to the dark side. The high concentration of the auxins on the dark side causes faster growth on the dark side, compared to the slow growth on the illuminated side causing the shoot to bend towards light.

2.      (SSCE, 2003 Q6) (a) (i) What is meant by growth in living organisms?

(ii) How does growth in plants differ from that of animals?

(b) Give an account of the factors that affect the rate of growth in plants animals.

(c) Describe an experiment to measure the rate of growth in the main root of a seedling.

Solution

(a)(i) Growth: is an irreversible increase in size and weight of an organism.

(ii) Due to meristems, plant growth occurs throughout their life. Growth ceases after sometime in animals because meristem do not occur in animals. Growth in plants is generally apical whereas growth occurs all over the body of animals.

(b) Factors affecting the rate of growth

¨      Hormones: hormones like auxins affect the rate of growth in plants.

¨      Genotype: dominant and recessive genes determine how proteins are synthesize.

¨      Nutrition: food for animals will determine its rate of growth.

¨      Environment: environmental factors have great influence in plants and animals growth. E.g. light is important for photosynthesis to take place as well as vitamin D synthesis.

(c) Take about ten bean seedlings and mark the radicle of each seedling with an Indian ink at 2mm, intervals. Measure the intervals at two day intervals and plot a graph of age on the x-axis and increase in length on y-axis. The gradient of the graph is taken which gives you the rate of growth. 

3.      (SSCE, 2004 Q7) (a) (i) What is meant by growth in organisms?

(ii) Distinguish between primary growth and secondary growth in plants.

(b) (i) What is auxin?

(ii) Describe an experiment to demonstrate that auxin is responsible for increase in the stem length of a seedling.

Solution

(a)(i) Refer to blog content

Primary growth: the growth in length of roots and stems result from activity of apical meristem.

Secondary growth: this is increase in girth or thickness of the stems and roots as result of activity of both primary and secondary meristems.

(b) (i) Auxin is plant hormones produced by shoot apical meristem tissue which promotes growth and  development of plants

(ii) Refer to blog content

                                             

 Click Here for WAEC Past Questions and Answers