Past Questions and Answers on Gaseous Exchange in Plants

SSCE/WASSCE/GCE PAST QUESTIONS AND ANSWERS

OBJECTIVES

1. Stomatal pores open when there is

A. an increase in the sugar content of guard cells

B. a decreases in the osmotic concentration of the guard cell

C. a decrease in the sugar content of mesophyll cells

D. an increase in the sugar content of mesophyll cells

2. In the woody stems, gaseous exchange takes place through the

A. micropyles C. lenticels

B. stomata D. vessels

3. The opening of the stoma is controlled by the

A. presence of a pore

B. increase in solute concentration in the guard cells

C. presence of guard cells

D. decrease in solute concentration in the guard cells

4. The opening and closing of the stoma are regulated by

A. transpiration C. diffusion

B. respiration D. osmosis

5. The stomatal pore is controlled by

A. epidermal cells C. mesophyll cells

B. guard cells D. subsidiay cells

Answers

1. A

2. C

3. B

4. D

5. B

LIKELY QUESTION

1. Name three structures of plant that involved in gaseous exchange

2. Explain how gaseous exchange occur through (i). stomata (ii). lenticel

3. Draw and label the structures involved in gaseous exchange