Question

Which of the following statements is correct?

• A. Some of the organisms can fix atmospheric nitrogen in specialized cells called sheath cells.
• B. Fusion of two cells is called Karyogamy.
• C. Fusion of protoplasms between two motile on non-motile gametes is called plasmogamy.
• D. Organisms that depend on living plants are called saprophytes.

Answer 1

Answer: (C)

Fusion of protoplasms between two motile on non-motile gametes is called plasmogamy.

Answer 2

Plasmogamy is the process of fusing the protoplasm (cytoplasm) of two gametes, whether they are motile or non-motile. This is a key step in the sexual reproduction of certain organisms, particularly fungi, where the fusion of cytoplasm precedes the fusion of nuclei (karyogamy).

Here's a brief explanation for each statement:

Option (A): Some organisms can fix atmospheric nitrogen in specialized cells called sheath cells. This statement is correct. Some cyanobacteria, like Anabaena, have specialized cells called heterocysts that can fix atmospheric nitrogen.

Option (B): Fusion of two cells is called Karyogamy. This statement is incorrect. Karyogamy is the fusion of two nuclei, which typically occurs during sexual reproduction, but it is not the fusion of two whole cells.

Option (D): Organisms that depend on living plants are called saprophytes. This statement is incorrect. Organisms that feed on dead or decaying organic matter are called saprophytes. Organisms that depend on living plants for nutrition are usually referred to as parasites.

So, option (C) is the correct one regarding plasmogamy, which is the fusion of protoplasms (cytoplasm) between two gametes.