AP BIOLOGY

Detailed explanation-1: -Chloroplast structure Chloroplasts contain fluid-filled sacs called thylakoids. Thylakoids are stacked up like pancakes to form structures which we call grana. Each granum is connected together by pieces of thylakoid membrane called lamellae. The gel-like substance which surrounds the thylakoids is called the stroma.

Detailed explanation-2: -What is stroma in a chloroplast? Stroma is the fluid-filled internal space of the chloroplasts which encircle the grana and the thylakoids. It contains chloroplast DNA, starch and ribosomes along with enzymes needed for the Calvin cycle.

Detailed explanation-3: -The space enclosed by the inner membrane is called the matrix in mitochondria and the stroma in chloroplasts. Both spaces are filled with a fluid containing a rich mixture of metabolic products, enzymes, and ions.

Detailed explanation-4: -The stroma is a gel-like substance that surrounds the thylakoid membranes in each chloroplast. Enzymes in the stroma take the ATP and convert it back into sugars that are then used by the plants.