Protion of gene which is transcribed but not translated is :-

Options

A. exon
B. intron
C. cistron
D. codon

Answer

To solve the question "Portion of gene which is transcribed but not translated is:", we will analyze the options provided and clarify the concepts involved.

### Step-by-Step Solution:

1. **Understanding Gene Structure**:
- Genes are segments of DNA that contain instructions for synthesizing proteins. They consist of coding regions (exons) and non-coding regions (introns).

2. **Defining Exons and Introns**:
- **Exons**: These are the coding sequences of a gene that are transcribed into mRNA and then translated into proteins.
- **Introns**: These are the non-coding sequences that are transcribed into mRNA but are removed during the RNA splicing process before translation occurs.

3. **Analyzing the Options**:
- **A. Exon**: This is incorrect because exons are translated into proteins.
- **B. Intron**: This is the correct answer as introns are transcribed into mRNA but are not translated into proteins.
- **C. Cistron**: This term refers to a segment of DNA that encodes a single polypeptide or protein, which is also not the answer.
- **D. Codon**: This is a sequence of three nucleotides in mRNA that corresponds to a specific amino acid, and it is involved in the translation process.

4. **Conclusion**:
- The portion of the gene that is transcribed but not translated is the **intron**.

### Final Answer:
The portion of the gene which is transcribed but not translated is **intron**.

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