Question

In the sieve elements, which one of the following is the most likely function of a P-proteins?

• A. Deposition of callose on sieve plates
• B. Providing energy for active translocation
• C. Autolytic enzymes
• D. None of the above

Answer 1

The correct option is B Providing energy for active translocation

In the sieve elements, the most likely function of P-proteins is providing energy for active translocation. Sieve tube members have no cell nucleus, ribosomes, or vacuoles. Thus, they depend on companion cells to provide proteins, ATP, and signalling molecules. In leaves, companion cells help move the sugar that is produced by photosynthesis from the mesophyll tissue into the sieve tube elements.

Thus, the correct answer is option B.