The first restriction enzyme was isolated from which bacteria

Options

A. E. coli
B. Haemophilus influenzae
C. Pseudomonas
D. Xanthomonas

Answer

To solve the question "The first restriction enzyme was isolated from which bacteria?", we can follow these steps:

### Step 1: Understand the question
The question is asking for the specific type of bacteria from which the first restriction enzyme was isolated. Restriction enzymes are proteins that cut DNA at specific sequences.

**Hint:** Think about the historical context of restriction enzymes and their discovery.

### Step 2: Identify the options
The options provided in the question are:
1. Lysine
2. Haemophilus Influenzae
3. Pseudomonas
4. Xanthomonas

**Hint:** Look for the bacteria that is known for its role in molecular biology and genetics.

### Step 3: Recall the historical background
The first restriction enzyme, known as "Nuclease," was discovered in the bacterium Haemophilus Influenzae. This bacterium is significant in the study of genetics and molecular biology.

**Hint:** Consider which of these bacteria are commonly studied in genetics and have been associated with the discovery of restriction enzymes.

### Step 4: Eliminate incorrect options
- Lysine is not a bacterium; it is an amino acid.
- Pseudomonas is known for its role in denitrification but is not associated with the first restriction enzyme.
- Xanthomonas is also not related to the discovery of restriction enzymes.

**Hint:** Focus on the options that are actual bacteria and have historical significance in the field of genetics.

### Step 5: Confirm the correct answer
Since Haemophilus Influenzae is the only bacterium listed that is known for the isolation of the first restriction enzyme, it is the correct answer.

**Final Answer:** The first restriction enzyme was isolated from **Haemophilus Influenzae**.

### Summary of Steps:
1. Understand the question.
2. Identify the options.
3. Recall the historical background of restriction enzymes.
4. Eliminate incorrect options.
5. Confirm the correct answer.