Which of the Following is a Correct Statement About Sugar

Question

Which of the following is a correct statement about sugar movement in phloem?
A) Diffusion can account for the observed rates of transport.
B) Movement can occur both upward and downward in the plant.
C) Sugar is translocated from sinks to sources.
D) Only phloem cells with nuclei can perform sugar movement.
E) Sugar transport does not require energy.

Accepted Answer

Sugar movement in phloem can occur in both upward and downward directions in the plant. This is because phloem cells have bidirectional transport capabilities, allowing them to transport sugars to wherever they are needed in the plant. Option A is incorrect because simple diffusion cannot account for the observed rates of transport in phloem, and option C is incorrect because sugar is actually translocated from sources (where it is produced, such as leaves) to sinks (where it is needed, such as growing roots). Option D is also incorrect because all phloem cells, including sieve tubes without nuclei, can perform sugar movement, and option E is incorrect because sugar transport in phloem requires energy in the form of ATP.