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 to ________.
A) determine if they have thylakoids in the chloroplasts
B) test for liberation of O2 in the light
C) test for CO2 fixation in the dark
D) do experiments to generate an action spectrum
E) test for production of either sucrose or starch

Question

Quizplus · Accepted Answer

The liberation of O2 in the light is a direct result of photosynthesis and is produced through the light-dependent reactions of photosystem II. If an organism lacks photosystem II, it will not produce O2 in the light, making this the best way to detect its absence. While thylakoids are necessary for photosynthesis, their presence alone does not indicate the presence of photosystem II. Testing for CO2 fixation in the dark or for the production of sucrose or starch would detect the overall process of photosynthesis, but not specifically the absence of photosystem II. Experimenting to generate an action spectrum would also not specifically detect the absence of photosystem II.

Some Photosynthetic Organisms Contain Chloroplasts That Lack Photosystem II Yet