Question

About how many chlorophyll molecules are found in a single photosynthetic unit and how many of

those chlorophyll molecules actually transfer electrons to an acceptor?

(1) 300, 200
(2) 300, 1
(3) 300, 300
(4) 2400, 300
(5) 2, 1

Answer 1

In a single photosynthetic unit, there are about 300 to 400 chlorophyll molecules, yet only a special pair of chlorophyll a molecules in the reaction center are capable of transferring electrons to an acceptor.

Step-by-step explanation:

The question is about the number of chlorophyll molecules found in a single photosynthetic unit and how many of those actually transfer electrons to an acceptor. Within a photosystem, there are multiple antenna proteins containing a mixture of 300 to 400 molecules of chlorophyll a and b, as well as other pigments. These antenna proteins form the light-harvesting complex that transfers solar energy to the reaction center, but only a pair of special chlorophyll a molecules actually transfer electrons when excited.

In the reaction center, this special pair, often referred to as P680 in photosystem II and P700 in photosystem I, is able to lose electrons upon excitation, transferring them to an electron acceptor. Therefore, among the hundreds of chlorophyll molecules present, only a single pair from each photosystem actually transfers an electron to start the process that eventually leads to the formation of ATP.

Thus, the correct option, given the information above, is (2) 300, 1, meaning that there are about 300 chlorophyll molecules in a photosystem unit, but only one chlorophyll molecule pair actually transfers electrons to an acceptor.