Question

Explain the structure of chloroplast.

Answer 1

Structure of chloroplast:

1. Chloroplasts are green-colored plastids present in plant cells that are responsible for photosynthesis.
2. Chloroplasts are flat, disc-shaped structures measuring 2-10mm in diameter and 1mm in thickness.
3. They have two membranes namely the outer and inner membranes. The outer membrane permits the movement of ions and metabolites whereas the inner membrane is highly specialized with transport proteins.
4. Both these membranes are phospholipid layers measuring 6-8nm in thickness.
5. These two membranes are separated by a gap of 10-20nm known as intermembrane space.
6. Each chloroplast has two definite regions namely, stroma and grana.
7. The fluid present inside the chloroplast is known as the stroma. Inside the stroma, there are interconnecting flattened membrane compartments known as stroma lamellae. It is the site of a dark reaction during photosynthesis(the process by which light energy is converted into chemical energy).
8. The stacked portion of membrane-bounded, flattened discs of the chloroplasts is known as grana. Each disc-like structure of grana is known as a thylakoid and the space within the thylakoid is known as thylakoid space. Granum is the site of light reaction during photosynthesis(the process by which light energy is converted into chemical energy).