Question

The pyrenoids are made up of

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

Answer 1

The Correct Option is A

The given question pertains to the structure of pyrenoids, which are organelles associated with the storage and synthesis of starch in algae and some plants. Let's analyze the options to determine the correct answer:

1. Option 1: Proteinaceous centre and starchy sheath

Pyrenoids are characterized by having a protein core surrounded by starch plates or a starchy sheath, which aids in the synthesis and storage of starch. This description matches the first option, indicating that the pyrenoids contain a proteinaceous center surrounded by a starchy sheath.

2. Option 2: Core of nucleic acid surrounded by protein sheath

This option suggests a structure that does not align with pyrenoids. Nucleic acids are not a core component of pyrenoids, making this option incorrect.

3. Option 3: Core of protein surrounded by fatty sheath

This option incorrectly describes the sheath as fatty; instead, pyrenoids are surrounded by a starchy sheath, making this not the accurate description.

4. Option 4: Core of starch surrounded by sheath of protein

This option inverses the actual arrangement found in pyrenoids. Instead of protein surrounding starch, it is starch surrounding a protein core, thus making this incorrect.

Thus, the correct answer is option 1: proteinaceous centre and starchy sheath. Pyrenoids are crucial for carbon fixation and starch formation in algae, with their structure supporting these functions.