What is not true for genetic code :-

Options

A. It is degerate
B. It is unambiguous
C. A codon in mRNA is read in a non-continuous fashion
D. it is nearly universal

Answer

To determine which statement is not true for the genetic code, we will analyze each of the provided options step by step.

### Step-by-Step Solution:

1. **Understanding the Genetic Code**:
The genetic code is a set of rules that defines how the sequence of nucleotides in DNA or RNA is translated into the sequence of amino acids in proteins.

2. **Analyzing the Statements**:
- **Statement 1**: "It is degenerate."
- **Explanation**: The genetic code is indeed degenerate, meaning that a single amino acid can be encoded by multiple codons. For example, the amino acid leucine can be encoded by six different codons (UUA, UUG, CUU, CUC, CUA, CUG).
- **Conclusion**: This statement is true.

- **Statement 2**: "It is unambiguous."
- **Explanation**: The genetic code is unambiguous, meaning that each codon specifies only one amino acid. For example, the codon AUG always codes for methionine.
- **Conclusion**: This statement is true.

- **Statement 3**: "A codon in mRNA is read in a non-continuous fashion."
- **Explanation**: Codons in mRNA are read in a continuous fashion without any gaps or punctuation. The ribosome reads the mRNA sequence from the start codon to the stop codon in a linear manner.
- **Conclusion**: This statement is not true.

- **Statement 4**: "It is nearly universal."
- **Explanation**: The genetic code is nearly universal, meaning that it is the same in most organisms, with few exceptions. For example, the same codons code for the same amino acids in humans, bacteria, and plants.
- **Conclusion**: This statement is true.

3. **Identifying the Incorrect Statement**:
From the analysis above, the statement that is not true for the genetic code is: "A codon in mRNA is read in a non-continuous fashion."

### Final Answer:
The statement that is not true for the genetic code is: **"A codon in mRNA is read in a non-continuous fashion."**

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