Assertion : All immunoglobulin molecules have a basic structure compsed of four polypeptide chains.
Reason : The polypeptide chains consists two identical heavy and light chain connected by disulphide bonds.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertin is true but reason is false.
D. If both assertion and reason are false.

Answer

To analyze the assertion and reason provided in the question, we can break it down into a step-by-step solution:

### Step 1: Understand the Assertion
The assertion states that "All immunoglobulin molecules have a basic structure composed of four polypeptide chains."
- **Explanation**: Immunoglobulins (antibodies) indeed have a basic structure that consists of four polypeptide chains: two identical heavy chains and two identical light chains.

### Step 2: Understand the Reason
The reason states that "The polypeptide chains consist of two identical heavy and light chains connected by disulfide bonds."
- **Explanation**: This statement is also true. In immunoglobulins, the two heavy chains and two light chains are connected by disulfide bonds, which help maintain the structure of the antibody.

### Step 3: Evaluate the Truth of the Assertion and Reason
Both the assertion and the reason are true statements about the structure of immunoglobulins.
- The assertion correctly describes the basic structure of immunoglobulins.
- The reason accurately explains how the chains are organized and connected.

### Step 4: Determine if the Reason Explains the Assertion
Since the reason provides a correct explanation for the assertion (it describes how the four polypeptide chains are formed and connected), we conclude that the reason supports the assertion.

### Conclusion
Both the assertion and the reason are true, and the reason is a correct explanation of the assertion.

### Final Answer
Both the assertion and the reason are true, and the reason correctly explains the assertion.

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