Question

Write a short note on grana and stroma.

Answer 1

Grana and Stroma:

1. Grana are stacked thylakoids, which are membrane-bound, flattened discoid sacs that hold chlorophyll molecules. They are the fundamental functioning units of chloroplasts.
2. Stroma is the homogenous matrix in which grana are embedded. Photosynthetic enzymes, starch grains, DNA, and ribosomes make up Stroma.
3. The granum is the site of light reaction during photosynthesis, while the stroma is the site of dark reaction.
4. There are two stages to photosynthesis.
5. In the first step of the light reaction, chlorophyll in the grana absorbs light.
6. A sequence of enzymes transports light energy through the thylakoid membrane, culminating in the synthesis of two energy-carrying compounds: ATP and NADPH.
7. During this process, water molecules are split, and oxygen is released as a waste product.