Question

multiple choice question
the transfer of phosphate from phosphoenol pyruvate (pep) to an incoming sugar molecule is an example of a(n) ______.

secondary transport
phosphorelay system
uniporter
symporter

Explanation:

• Secondary transport: Involves using an electrochemical gradient (not phosphate transfer as in the question).
• Phosphorelay system: Transfers phosphate groups in a series, and the transfer of phosphate from PEP to a sugar (like in sugar transport/phosphorylation) is part of a phosphorelay - type mechanism (e.g., in group translocation where phosphate is transferred to the incoming molecule).
• Uniporter: Transports a single molecule down its concentration gradient, not related to phosphate transfer.
• Symporter: Transports two molecules in the same direction, not about phosphate transfer.

Answer:

B. phosphorelay system