Question

A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the organelles. Organelles in one of the heavier fractions could produce ATP in the light, while organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions are most likely to contain, respectively

Answer 1

Chloroplast and mitochondria respectively

Step-by-step explanation:

The chloroplast is the organelle wherein ATP is produced by the process of photophosphorylation during the light-dependent phase of photosynthesis. The transfer of electrons from PSII to PSI via electron transport chain generates a proton concentration gradient across the thylakoid membrane which in turn drives the process of ATP synthesis.

Mitochondria can produce ATP in the absence of light by the process of oxidative phosphorylation. Oxidation of NADH and FADH2 via electron transport chain generates a proton concentration gradient across the inner membrane of mitochondria which in turn drives the process of ATP synthesis