In the year 1958,Matthew meselson and franklin stahl proved the semiconservative replication of DNA in a

Options

A. plant
B. bacterium
C. fungus
D. virus

Explanation

To solve the question regarding the experiment conducted by Matthew Meselson and Franklin Stahl in 1958, we need to identify the organism in which they proved the semiconservative replication of DNA. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Scientists and Their Experiment
- The scientists in question are Matthew Meselson and Franklin Stahl. They conducted a significant experiment in 1958 that demonstrated the mechanism of DNA replication.

**Hint:** Remember the names of the scientists and the year of their experiment as it is crucial for understanding the context.

### Step 2: Understand the Concept of Semiconservative Replication
- Semiconservative replication means that during DNA replication, each of the two resulting DNA molecules has one original (parental) strand and one newly synthesized strand.

**Hint:** Focus on the definition of semiconservative replication, as it is key to understanding the significance of the experiment.

### Step 3: Identify the Organism Used in the Experiment
- Meselson and Stahl used **E. coli**, a type of bacterium, for their experiments. They chose E. coli because it has a short generation time (approximately 20 minutes), making it suitable for their study.

**Hint:** Recall that the choice of organism is important in experiments, especially in genetics, due to factors like generation time.

### Step 4: Describe the Experimental Setup
- They grew E. coli in a medium containing heavy nitrogen (specifically, ammonium chloride with the nitrogen-15 isotope). This allowed them to trace the DNA strands through generations.

**Hint:** Pay attention to the experimental conditions, such as the use of heavy nitrogen, as they are critical to the results obtained.

### Step 5: Analyze the Results
- After growing the bacteria for two generations, they observed a mixture of hybrid DNA (one heavy and one light strand) and light DNA (both strands light), confirming the semiconservative nature of DNA replication.

**Hint:** Understanding the results is essential; they provide evidence for the theory of semiconservative replication.

### Step 6: Conclusion
- Based on the above steps, we conclude that Meselson and Stahl proved the semiconservative replication of DNA in **E. coli**.

**Hint:** Always summarize your findings to reinforce the main conclusion of the experiment.

### Final Answer
The correct answer is that Matthew Meselson and Franklin Stahl proved the semiconservative replication of DNA in **E. coli**.