The Living World 8th Edition by George Johnson

Exercise 6

Plants use two photosystems to capture energy used to produce ATP and NADPH. The electrons used in these photosystems
A) recycle through the system constantly, with energy added from the photons.
B) recycle through the system several times and then are lost due to entropy.
C) go through the system only once; they are obtained by splitting a water molecule.
D) go through the system only once; they are obtained from the photon.
In plants,
A) photosystem I acts before photosystem II.
B) photosystem II acts before photosystem I.
C) photosystems I and II act simultaneously.
D) only photosystem II is present.