Assertion : In protoplasm, protoplasm , protein functions as a buffer .
reason : the protein molecule is amphotieric .

Options

A. If both assertion and Reason are true and the Reason is the correct explanation of the assertion .
B. If both Assertion and Reason ate true , but the reason is not the correct explanation of the assertion .
C. If Assertion is true , but Reason is false
D. if both Assertion and Reason are false.

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that in protoplasm, protein functions as a buffer. This means that proteins help to maintain a stable pH in the protoplasm by resisting changes in acidity or alkalinity.

2. **Understanding the Reason**: The reason given is that the protein molecule is amphoteric. An amphoteric molecule can act as both an acid and a base, meaning it can either donate or accept protons (H+ ions).

3. **Role of Amino Acids in Proteins**: Proteins are made up of amino acids, which contain both a positively charged amino group (NH2) and a negatively charged carboxyl group (COOH). This dual nature allows amino acids to interact with hydrogen ions (H+) and hydroxyl ions (OH-), thus helping to stabilize pH levels.

4. **Buffering Action of Proteins**: When the pH of the protoplasm changes, the amino acids in proteins can either donate protons when the environment is too basic or accept protons when the environment is too acidic. This ability to react to changes in pH is what makes proteins effective buffers.

5. **Conclusion**: Both the assertion and the reason are true. The assertion that proteins function as buffers in protoplasm is correct, and the reason that proteins are amphoteric is also correct. Furthermore, the reason correctly explains why the assertion is true.

### Final Answer:
Both the assertion and the reason are true, and the reason is the correct explanation of the assertion.

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