Which of the following processes is ''semi conservative'' ?

Options

A. translation
B. transcription
C. replication
D. reverse transcription

Answer

**Step-by-Step Solution:**

1. **Understanding Semi-Conservative Replication:**
- The term "semi-conservative" refers to a method of replication where each new DNA molecule consists of one original strand and one newly synthesized strand. This means that half of the original DNA is conserved in each new DNA molecule.

2. **Identifying the Process:**
- The process that is described as semi-conservative is DNA replication. During this process, the double-stranded DNA unwinds and separates into two single strands. Each original strand serves as a template for the synthesis of a new complementary strand.

3. **Example of Semi-Conservative Replication:**
- A classic experiment demonstrating semi-conservative replication was conducted using E. coli bacteria. In this experiment, E. coli was grown in a medium containing nitrogen-15 (N15), a heavy isotope of nitrogen. After several generations, the bacteria were then transferred to a medium containing nitrogen-14 (N14), a lighter isotope.

4. **Analyzing the Results:**
- After the first round of replication in the N14 medium, the resulting DNA molecules contained one strand with N15 and one strand with N14, creating a hybrid DNA molecule. This shows that one original strand (N15) was conserved while a new strand (N14) was synthesized.
- In subsequent generations, the DNA would continue to exhibit this semi-conservative nature, with the proportion of N14 increasing while N15 decreases, but always retaining one strand from the previous generation.

5. **Conclusion:**
- Therefore, the process that is semi-conservative is DNA replication. This ensures that genetic information is accurately passed on to the next generation of cells.