alleryStart learning →On what basis do the two photosystems differ from each other?
AOn whether they contain any protein at all
BOn what they oxidize and what they reduce
COn which wavelength of light they reflect
DOn how many membranes surround each one
Answer & Solution
Correct answer: B. On what they oxidize and what they reduce
1. Both photosystems share the same basic structure of antenna proteins around a reaction centre.
2. They differ on the basis of what they oxidize and what they reduce.
3. What they oxidize is where their low-energy electron supply comes from.
4. What they reduce is the place to which they deliver their energised electrons.
5. Photosystem II takes its replacement electrons from water, while photosystem I takes them from the chain.
6. Both are protein complexes in the same membrane, so the structural options describe no real difference.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 8 "Photosynthesis", section 8.2 The Light-Dependent Reactions of Photosynthesis_
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