Who identified the biochemical nature of transforming substance?

Options

A. 1.Oswald Avery and Colin Macleod
B. 2.Maclyn McCarty
C. 3.F. Griffith
D. 4.Both (1) and (2)

Answer

To solve the question "Who identified the biochemical nature of transforming substance?", we can follow these steps:

### Step 1: Understand the Context
The question refers to the identification of the biochemical nature of a substance that can transform one type of bacteria into another. This concept is foundational in genetics and molecular biology.

**Hint:** Look for key experiments related to bacterial transformation.

### Step 2: Identify Key Experiments
The discovery of the biochemical nature of the transforming substance is linked to experiments conducted in the early 20th century, specifically between 1933 and 1944. The key experiment involved the transformation of R-strain bacteria into S-strain bacteria.

**Hint:** Recall the experiments involving heat-killed bacteria and live bacteria.

### Step 3: Recognize Key Figures
The main contributors to this discovery were Oswald Avery, Colin McLeod, and Matthew McCarty. They conducted experiments that demonstrated that DNA was the transforming substance.

**Hint:** Remember the names associated with the transformation experiments.

### Step 4: Analyze the Options
The options provided are:
1. Oswald Avery and Colin McCarty
2. Maclean McCarty
3. F. Griffith
4. Option 1 and Option 2

From the context, we can see that F. Griffith initially discovered the transformation phenomenon, but it was Avery, McLeod, and McCarty who identified the biochemical nature of the transforming substance.

**Hint:** Differentiate between the discoverer of the phenomenon and those who identified its biochemical nature.

### Step 5: Conclusion
The correct answer to the question is option 2, which includes both Oswald Avery and Colin McLeod, as they were instrumental in identifying the biochemical nature of the transforming substance.

**Final Answer:** Option 2 (both Oswald Avery and Colin McLeod).