Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be
A) to determine if they have thylakoids in the chloroplasts.
B) to test for liberation of O₂ in the light.
C) to test for CO₂ fixation in the dark.
D) to do experiments to generate an action spectrum.
E) to test for production of either sucrose or starch.

Question

Quizplus · Accepted Answer

Photosystem II is necessary for the light-dependent generation of oxygen, so a test for liberation of O₂ in the light would be a reliable way to detect the lack of photosystem II in photosynthetic organisms. Option A is not specific to the presence or absence of photosystem II, as thylakoids are present in all chloroplasts. Option C is not a reliable way to detect photosystem II, as CO₂ fixation can occur without photosystem II. Option D is more related to determining the absorption spectrum of pigments than the presence or absence of photosystem II. Option E is not a reliable way to detect photosystem II, as sucrose or starch production can occur in the absence of photosystem II.

Some Photosynthetic Organisms Contain Chloroplasts That Lack Photosystem II, Yet