Which is not nucleotide component ?

Options

A. Thymine
B. Guanine
C. Lysine
D. Adenine.

Answer

To determine which option is not a nucleotide component, we need to understand the structure of a nucleotide. A nucleotide consists of three main components:

1. **Nitrogenous Base**: This can be further classified into two categories:
- **Purines**: Adenine and Guanine
- **Pyrimidines**: Cytosine, Thymine (in DNA), and Uracil (in RNA)

2. **Sugar**: The sugar in a nucleotide can either be:
- **Ribose** (in RNA)
- **Deoxyribose** (in DNA)

3. **Phosphate Group**: This is the third component that links nucleotides together to form nucleic acids.

Now, let's analyze the options provided in the question:

- **Thymine**: This is a pyrimidine nitrogenous base and is a component of nucleotides (specifically in DNA).

- **Guanine**: This is a purine nitrogenous base and is also a component of nucleotides.

- **Lysine**: This is an amino acid, specifically a basic amino acid, and is **not** a component of nucleotides.

- **Adenine**: This is another purine nitrogenous base and is a component of nucleotides.

From this analysis, we can conclude that the correct answer is **Lysine**, as it is not a nucleotide component.

### Final Answer:
**Lysine is not a nucleotide component.**