Assertion (A): Some codons act as terminating or stop codons.
Reason ( R): 3 codons do not code for any amino acids.

Options

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true

Explanation

To solve the question regarding the assertion and reason provided, we can break it down step by step:

### Step 1: Understand the Assertion
The assertion states that "Some codons act as terminating or stop codons."
- Codons are sequences of three nucleotides in mRNA that correspond to specific amino acids or signals during protein synthesis.
- Terminating or stop codons signal the end of protein synthesis.

**Hint:** Recall what codons are and their role in protein synthesis.

### Step 2: Identify the Stop Codons
The reason states that "3 codons do not code for any amino acids."
- The three codons that serve as stop codons are UAG, UAA, and UGA.
- These codons do not code for any amino acids; instead, they signal the ribosome to stop translation.

**Hint:** Remember the specific stop codons and their function in translation.

### Step 3: Analyze the Relationship Between Assertion and Reason
- The assertion is true because there are indeed codons that function as stop codons.
- The reason is also true because the three stop codons do not correspond to any amino acids.

**Hint:** Consider how the reason supports the assertion.

### Step 4: Conclusion
Since both the assertion and the reason are true, and the reason correctly explains the assertion, we conclude that the assertion and reason are both valid.

**Final Answer:** Option 1 is correct: Both the assertion and reason are true, and the reason supports the assertion.