Question

To what does the term stroma refer?

A. the double membrane of the chloroplast
B. a flattened disk or sac in the chloroplast
C. a stack of thylakoid membrane structures
D. the central fluid-filled space of the chloroplast
E. the cytochrome system in the membranes of the thylakoids

Answer 1

The stroma is the fluid-filled space inside a chloroplast that surrounds the thylakoid stacks (grana) and is involved in the Calvin cycle of photosynthesis.

Step-by-step explanation:

The term stroma refers to the liquid-filled space within the chloroplast enclosed by the inner membrane, which surrounds the grana. Grana, the plural being granum, are stacks of thylakoids, the disc-shaped structures where the light-dependent reactions of photosynthesis occur.

The stroma contains enzymes necessary for the synthesis of organic molecules in the Calvin cycle, a process of photosynthesis that occurs after the light-dependent reactions. Embedded within the thylakoid membranes is chlorophyll, the pigment that captures light energy. The stroma plays a crucial role in converting inorganic carbon dioxide into organic compounds.