Multiple choice questions on Phloem Transport

1. The long-distance transport of photosynthate from one region to another in higher plants is called

a) xylem translocation

b) phloem translocation

c) apoplast

d) symplast

2. All the following are ‘sink’ except

a) fruit

b) seed

c) leaves

d) rhizome

3. Which of the following is a ‘source’?  

a) green parts

b) Fruit

c) tubers

d) seed

4. The movement of photosynthate through phloem is always

a) from source to sink

b) from sink to source

c) bi directional

d) none of these

5. The process of transferring sugar formed in mesophyll cells to sieve tubes of phloem is called

a) photosynthate transfer

b) source-sink transfer

c) phloem loading

d) phloem unloading

6. Phloem unloading occurs

a) from low concentration to high concentration

b) with concentration gradient

c) against concentration gradient

d) remains same

7. Phloem loading is the transfer of sugar from

a) source to sink

b) Leaves to sieve tubes

c)  fruits to seed

d)  all of these

8. All the following statements are false regarding phloem loading except

a) Phloem loading is from phloem cells to leaves

b) phloem loading occurs in concentration gradient

c) Phloem loading is an active process

d)  phloem loading is from sink to source

9. The process of transferring sugar from sieve tubes to sink is called

a) photosynthate transfer

b) source sink transfer

c) phloem loading

d) phloem unloading

10. According to Mass flow hypothesis, mass flow of solute from source to sink is due to  

a) concentration gradient

b) turgor pressure gradient

c) osmosis

d) osmosis and diffusion

Answers:

1. b) phloem translocation

2. c) leaves

3. a) green parts

4. a) from source to sink

5. c) phloem loading

6. b) with concentration gradient

7. d)  all of these

8. c) Phloem loading is an active process

9. d) phloem unloading

10.b) turgor pressure gradient