Question

Which part of pond scum turns blue when treated with iodine?

• A. Nucleus
• B. Pyrenoid
• C. Nucleolus
• D. Vacuole

Answer 1

The correct option is B

Pyrenoid

The correct option is B.

Explanation of the correct option:

1. Pyrenoid of pond scum turns blue when treated with iodine.
2. Pond scums are filamentous green algae.
3. Pyrenoids are located in chloroplasts.
4. These contain proteins as well as starch, and hence during the iodine test, these turn blue.

Explanation of the incorrect option:

Option A:

The nucleus is the double membrane-bound cell organelle, that contains genetic materials. It regulates all cellular activities by controlling the enzymes required for the cellular processes.

Option C:

The nucleolus is a small spherical structure located in the nucleus. It is the site of the synthesis of active ribosomal RNA synthesis.

Option D:

A vacuole is a membrane-bound space found in the cytoplasm. It contains water, sap, waste products and other materials of the cell.

Final Answer:

Pyrenoid of pond scum turns blue when treated with iodine.