From the following, how many amino acids contain sulphur in their chemical structure?
Methionine, histidine, threonine, cysteine, alanine, tryptophan, valine

Options

A. Three
B. Five
C. Two
D. Four

Answer

To determine how many amino acids from the given list contain sulfur in their chemical structure, we will analyze each amino acid one by one.

### Step-by-Step Solution:

1. **List the Amino Acids**: The amino acids provided in the question are:
- Methionine
- Histidine
- Threonine
- Cysteine
- Alanine
- Tryptophan
- Valine

2. **Identify Sulfur-Containing Amino Acids**:
- **Methionine**: This amino acid contains sulfur in its structure. It has a thioether group (–S–).
- **Histidine**: This amino acid does not contain sulfur.
- **Threonine**: This amino acid does not contain sulfur.
- **Cysteine**: This amino acid contains sulfur in its structure. It has a thiol group (–SH).
- **Alanine**: This amino acid does not contain sulfur.
- **Tryptophan**: This amino acid does not contain sulfur.
- **Valine**: This amino acid does not contain sulfur.

3. **Count the Sulfur-Containing Amino Acids**: From the analysis, we find that:
- Methionine: Contains sulfur
- Cysteine: Contains sulfur
- Histidine, Threonine, Alanine, Tryptophan, Valine: Do not contain sulfur

Therefore, the total number of amino acids containing sulfur is 2 (Methionine and Cysteine).

### Final Answer:
The total number of amino acids that contain sulfur in their chemical structure is **2**.