Which of the following statements about amino acids is incorrect ?

Options

A. Essential amino acids are not synthesised in the body, therfore have to be provided in the diet.
B. Leucine, isoleucine, lysine, valine are essential amino acids.
C. Cysteine and methionine are sulphur containing amino acids.
D. Lysine and arginine are acidic amino acids.

Explanation

To determine which statement about amino acids is incorrect, let's analyze each option provided in the question step by step.

### Step-by-Step Solution:

1. **Understanding Essential Amino Acids**:
- Essential amino acids are those that cannot be synthesized by the body and must be obtained through the diet.
- **Evaluation**: The statement "Essential amino acids are synthesized in the body therefore have to be provided in the diet" is incorrect because essential amino acids are not synthesized in the body.

2. **Identifying Essential Amino Acids**:
- The amino acids leucine, isoleucine, lysine, and valine are indeed classified as essential amino acids.
- **Evaluation**: The statement "leucine, isoleucine, lysine, valine are essential amino acids" is correct.

3. **Sulfur-Containing Amino Acids**:
- Cysteine and methionine are known to contain sulfur in their structure.
- **Evaluation**: The statement "cysteine and methionine are sulfur containing amino acids" is correct.

4. **Classifying Amino Acids**:
- Lysine and arginine are classified as basic amino acids, not acidic amino acids.
- **Evaluation**: The statement "lysine and arginine are acidic amino acids" is incorrect.

### Conclusion:
The incorrect statement among the options provided is:
- **Option 4**: "lysine and arginine are acidic amino acids."

### Final Answer:
**The incorrect statement about amino acids is: "lysine and arginine are acidic amino acids."**

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