Question

When a storage structure like a potato converts starch into sucrose so that it can be loaded into the phloem, which membrane transport proteins is it likely to use?

a. K+ channel
b. Cl channel
c. H+ pump
d. Co-transport proteins
e. C and D

Answer 1

The storage structure uses a co-transport protein called the sucrose-H+ symporter to load sucrose into phloem cells.

Step-by-step explanation:

The storage structure, like a potato, uses a carrier protein called the sucrose-H+ symporter to actively transport sucrose into the phloem cells. This symporter uses the electrochemical potential of the proton gradient to load sucrose against its concentration gradient. Therefore, the membrane transport protein likely to be used is a co-transport protein (Option D).