Question

Both grana and stroma are:.....

Answer 1

Hint: Stroma is the fluid-filled inner space of chloroplasts that surrounds thylakoids and grana. Grana, the plural of granum, are stacks of structures called thylakoids, which are small discs of membrane on which light-dependent photosynthesis reactions occur.

Complete answer:
Higher plants contain chloroplasts. They have the pigment chlorophyll and participate in photosynthesis. Each chloroplast is divided into two distinct regions and is bounded by two unit membranes.
1. Grana are stacks of membrane-bound, flattened discoid sacs called thylakoids that contain chlorophyll molecules. They are the chloroplasts' primary functional units.

2. The homogeneous matrix in which grana are embedded is known as stroma. Stroma is made up of photosynthetic enzymes, starch grains, DNA, and ribosomes. During photosynthesis, the granum is the site of light reaction, while the stroma is the site of dark reaction.

Photosynthesis occurs in two stages. Chlorophyll in the grana absorbs light in the first step of the light reaction. The energy from light is transferred through the thylakoid membrane by a series of enzymes, resulting in the production of two energy-carrying compounds: ATP and NADPH. Water molecules are split during this process, and oxygen is released as a waste product.

The dark reaction, the second step, takes place in the stroma. The energy stored in NADPH and ATP drives a reaction that produces the sugar glucose from carbon dioxide and water. Glucose is a source of nutrition for the plant.

Both grana and stroma are parts of chloroplasts.

Note: Chloroplasts can have between 10 and 100 grana. Stroma thylakoids, also known as intergranal thylakoids or lamellae, connect grana. The protein composition of grana thylakoids and stroma thylakoids distinguishes them. Grana contributes to the high surface area to volume ratio of chloroplasts.