Past Questions and Answers on Transport in Plant



1.      Mineral salts can be absorbed into the roots by
A. osmosis only
B. osmosis and diffusion
C. diffusion and active transport
D. imbibition only

2.       A physiological adaptation of plants to the problem of excessive water loss is
A. reduction in the number of stomata
B. reversal of the normal stomatal rhythm
C. possession of shallow roots
D. possession of waxy cuticle

3.      If a ring of bark and phloem is removed from a stem, the
A. plant dies immediately
B. plant dies after two days
C. movement of food is not affected
D. movement of minerals is hardly affected

4.      Transpiration can be measured with a
A. photometer        
B. hygrometer      
C. potometer  
D. barometer

5.      Which of the following can bring about the greatest increase in the rate of transpiration?
A. Increased humidity
B. Reduced temperature
C. Reduced wind speed
D. Reduced humidity

6.      Manufactured food in the plant is transported through the
A. xylem                   
B. phloem           
C. cambium      
D. cortex

7.      Oozing out of water from the leaves of plants in a humid environment is known as
A. transpiration          
B. osmosis            
C. pinocytosis         
D. guttation

8.      In the whistling pine, leaves are reduced to brown scales and young stems are green. This is an adaptation for
A. obtaining food
B. conserving nutrients
C. storing water
D. reducing transpiration

9.      Substance manufactured by the leaves are transported to other parts of the plant through the
A. xylem                      
B. companion cells     
C. sieve tubes   
D. cambium

10.  The force that holds water together in the form of a stream within the xylem tube is the
A. cohesion of water molecules to one another by hydrogen bonds
B. force of gravity attacking the water molecules through the hydrogen bonds
C. attraction between the water and xylem osmotic force
D. normal flow of water from the ground with help of gravitational force

11.    Salts and water are absorbed in the roots and transported to leaves by
A. diffusion through the xylem tissues
B. osmosis through the phloem tissues
C. diffusion through the phloem tissues
D. osmosis through the xylem tissues

12.    If water that has been coloured red is poured at the base of a wilting plant, it will appear as a red stain in the cells of the
A. xylem                   
B. epidermis        
C. phloem     
D. parenchyma

13.    The presence of sunken stomata and the folding of leaves are adaptations to
A. Prevent entry of pathogens
B. Reduce water loss
C. Remove excess water
D. Prevent guttation

14.    Excess water in plants is excreted as water vapour and droplets respectively through
A. respiration and guttation
B. transpiration and guttation
C. photosynthesis and guttation
D. guttation and condensation

15.    The loss of water vapour through the aerial parts of the plant to the atmosphere is called
A. respiration           
B. guttation              
C. osmoregulation      
D. transpiration

16.    The upward movement of the sap in the xylem vessel is brought about by
A. transpiration stream       
B. guttation           
C. capillarity             
D. osmosis

17.    Water vapor is lost in plants during transpiration through
A. stomata and lenticels
B. xylem and stomata
C. sclerenchyma and stomata
D. parenchyma and lenticels

18.    Transpiration enhances
A. continuous stream of water through the plant
B. absorption of water by the plant cell
C. continuous closure of the stomata
D. translocation of plant food

19.    Which of the following pathway is taken from soil to xylem?
A. root hair→ piliferous layer → xylem
B. root hair → cortex →piliferousblayer → xylem
C. root hair → piliferous layer → cortex → xylem
D. root hair → cortex → xylem

20.    Which of the following statement about transpiration is true?
A. the plant is cooled during transpiration
B. transpiration occurs most in upper surface of a leaf
C. transpiration occur only in leaves
D. transpiration occurs more in the night than in the day


1. C

6. B

11. D

16. C

2. B

7. D

12. A

17. A

3. D

8. D

13. B

18. A

4. C

9. B

14. B

19. C

5. D

10. A

15. D

20. A


1.      (SSCE 1998) (a) Explain how plant obtains
(i) Water               
(ii) mineral salts

(b) Describe the pathway and mechanisms of water transport in the plant.


(a) (i) Water is mainly absorbed by root hairs of plants. They are numerous and greatly increase the surface area of the root available for absorption. They lack cuticle and have thin cell walls. All these characteristics are adaptations of roots for absorption of water from the soil by osmosis.

(ii) Mineral salts are found in ionic form, dissolved in the soil water surrounding the roots. Depending on the mineral salt required by the plant, the roots hairs absorb the salts by diffusion along concentration gradient or against concentration gradient by active transport.

(b) Water enters the root hairs by osmosis. Water from the soil, dilutes the cell sap of the root hair and moves across the cortex along an osmotic gradient, into the xylem. Continuous absorption of water by root hairs generates a pressure called root pressure, moves water along the xylem. As a result of cohesion, adhesion and capillarity through xylem vessel, water moves from the xylem through the cells of the lamina by osmosis, which results from transpiration through the stomata. The transpiration also set up tension in the xylem vessels. This tension pulls the rest of the water column upwards, a process known as transpiration pull. 

2.  (SSCE 2004 Q5) (a) (i) How can it be proved experimentally that plants lose water during transpiration?
(ii) Name four environmental factors that affect the rate of rate transpiration in plants.

(b) What is the importance of transpiration to plants?
(c) List four features of plant that enable them to control excessive loss of water through plants transpiration.

(a)   (i) Refer to blog content
(ii) Temperature, light, wind, relative humidity

(b) Refer to blog content

(c) Modifications controlling excessive loss of water
·         Curled up leaves       
    Sunken stomata
·         Presence of hairs and scales
·         Presence of thick cuticle
·         Reduction of leaf size

3. (SSCE 2005 Q1) (a) (i) Distinguish between transpiration and guttation.
(ii) Under what condition does guttation occur?

(b) (i) Describe the mechanism of transpiration
(ii) What is the importance of transpiration? 


Transpiration is the loss of water in the form of water vapor from the aerial parts of the plant mainly through the leaves while

Guttation is the exuding of drops of water on the tips or edges of leaves.  

(ii) Refer to blog content

(b) Mechanism of transpiration

Water molecules evaporate from the surface of spongy mesophyll cells into the intercellular spaces. Where the water diffuses out through the stomata into the atmosphere. The sap of the mesophyll cell become more concentrated and water is drawn into them from neighboring cells by osmosis. This continues until the water is eventually drawn from the xylem vessels in the veins. 

(ii) Refer to blog content

4. (WASSCE 2014) Name the biological phenomenon used to describe loss water from plants when transpiration is impossible.

(ii) State two condition under which the phenomenon named in (f)(i) above occurs


(f)(i) Guttation

(ii) Refer to blog content

Click Here for WAEC/ SSCE WASSCE NOVDEC Biology Past Questions and Answers



Post a Comment