Control of gene experssion takes place at the level of

Options

A. DNA-replication
B. Transcription
C. Translation
D. None of these

Answer

To solve the question "Control of gene expression takes place at the level of," we need to analyze the options provided and understand the processes involved in gene expression.

### Step-by-Step Solution:

1. **Understanding Gene Expression**:
- Gene expression refers to the process by which the information encoded in a gene is used to produce a functional product, typically a protein. This involves several stages: DNA replication, transcription, and translation.

2. **Identifying the Stages**:
- **DNA Replication**: This is the process of copying DNA to produce two identical DNA molecules. It does not involve gene expression but rather the duplication of genetic material.
- **Transcription**: This is the process where the DNA sequence of a gene is transcribed to produce messenger RNA (mRNA). This is a critical step in gene expression as it determines which genes are expressed at any given time.
- **Translation**: This is the process where the mRNA is translated into a polypeptide chain (protein). While this is part of gene expression, the actual control of which genes are expressed occurs before this step.

3. **Determining the Correct Answer**:
- Since gene expression is primarily controlled at the transcription level, the correct answer to the question is **transcription**.

4. **Final Answer**:
- The control of gene expression takes place at the level of **transcription**.