Question

Which of the following statements correctly describes a reaction associated with photosystem I?

Options:
A. Light energy excites electrons in the thylakoid membrane electron transport chain.
B. Electrons released from the chlorophyll are replaced by electrons derived from water.
C. The P680 chlorophyll donates a pair of electrons directly to NADP+ producing NADPH.
D. Electrons are passed from the P680 chlorophyll to oxygen (O2).

Answer 1

The correct statement that describes a reaction associated with photosystem I is that the P680 chlorophyll donates a pair of electrons directly to NADP+ producing NADPH.

Step-by-step explanation:

The correct statement that describes a reaction associated with photosystem I is C. The P680 chlorophyll donates a pair of electrons directly to NADP+ producing NADPH.

In photosystem I, the chlorophyll molecule known as P680 donates a pair of electrons to NADP+, which is then reduced to NADPH. This electron transfer occurs after the light energy excites electrons in the thylakoid membrane electron transport chain. However, the specific details provided in the options are not entirely accurate for photosystem I reactions. In photosystem I (PSI), light energy is absorbed by pigments and transferred to the PSI reaction center containing chlorophyll a molecules known as P700.

By donating its electrons, P680 becomes positively charged and needs to be replenished. This is achieved through the transfer of electrons from photosystem II to photosystem I through the electron transport chain.