A: Restriction enzymes belong to a larger class of enzymes called nucleases.
R: Each restriction enzymes recognises sequence in the DNA.

Options

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

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided.

### Step 1: Understand the Assertion (A)
The assertion states that "Restriction enzymes belong to a larger class of enzymes called nucleases."

- **Explanation**: Nucleases are enzymes that cleave the bonds between nucleotides in nucleic acids (DNA and RNA). There are two main types of nucleases:
- **DNases**: These enzymes specifically degrade DNA.
- **RNases**: These enzymes specifically degrade RNA.

Since restriction enzymes are indeed enzymes that cut DNA at specific sites, they fall under the category of nucleases.

### Step 2: Understand the Reason (R)
The reason states that "Each restriction enzyme recognizes a sequence in the DNA."

- **Explanation**: Restriction enzymes are known for their ability to recognize specific sequences of nucleotides in DNA, typically palindromic sequences. This means that the sequence reads the same forwards and backwards. Upon recognizing these sequences, restriction enzymes cut the DNA at these specific sites.

### Step 3: Evaluate the Relationship Between A and R
Now we need to determine if the reason explains the assertion.

- While both statements are true (A is true, and R is true), the reason (R) does not explain why restriction enzymes are classified as nucleases. It merely describes a characteristic of restriction enzymes.

### Conclusion
Both the assertion and the reason are true, but the reason does not serve as a correct explanation for the assertion.

### Final Answer
The correct option is: **Option 2: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.**

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