A : Tertiary structure of protein is absoulutely necessary for many biological actitives of proteins.
R : In protein, only right handed helices are observed.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
C. If Assertion is true statements but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the assertion and reason question, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
The assertion states that "the tertiary structure of protein is absolutely necessary for many biological activities of proteins."

- **Explanation**: The tertiary structure of a protein refers to the overall three-dimensional shape formed by the folding and bending of polypeptide chains. This structure is stabilized by various types of bonds, including hydrogen bonds, ionic bonds, disulfide bridges, and van der Waals forces. The specific shape of a protein is crucial because it determines how the protein interacts with other molecules, which is essential for its biological function. Therefore, the assertion is **true**.

### Step 2: Analyze the Reason
The reason states that "in protein, only right-handed helices are observed."

- **Explanation**: In proteins, the secondary structure can include alpha helices, which are typically right-handed. This means that the spiral structure twists in a right-handed direction. Right-handed helices are more stable and commonly found in nature, while left-handed helices are rare and less stable. Thus, the reason is also **true**.

### Step 3: Determine the Relationship Between Assertion and Reason
Now we need to determine if the reason provided is the correct explanation for the assertion.

- The assertion discusses the importance of the tertiary structure for biological activity, while the reason focuses on the presence of right-handed helices in proteins. Although both statements are true, the reason does not explain why the tertiary structure is necessary for biological activity. Therefore, the reason is not a correct explanation for the assertion.

### Conclusion
Both the assertion and reason are true, but the reason is not the correct explanation of the assertion. Hence, the correct answer is option 2: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

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