Question

Pyrenoids are made up of?

• A. Core of starch surrounded by sheath of protein
• B. Core of protein surrounded by fatty sheath
• C. Proteinaceous centre and starchy sheath
• D. Core of nucleic acid surrounded by protein sheath

Answer 1

The correct option is C

Proteinaceous centre and starchy sheath

The correct option is C.

Explanation of the correct option:

1. Pyrenoids are non-membrane-bound organelles composed of proteinaceous centres and starchy sheaths found in chloroplasts.
2. The function of pyrenoids is to facilitate photosynthetic CO₂ fixation by the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase.

Explanation of the incorrect options:

Option A:

The centre contains protein and the sheath is made up of starch.

Option B:

The sheath is made up of starch, not fatty acids.

Option D:

The centre contains protein, not nucleic acid and the sheath is made up of starch not protein.

Final answer: Pyrenoids are made up of proteinaceous centre and starchy sheath.