Peptide bond present in all, except:-

Options

A. Polypeptide
B. Enzyme
C. Amino acid
D. Protein

Answer

To solve the question "Peptide bond present in all, except:-", we will analyze each option provided and determine where peptide bonds are present or absent.

### Step-by-Step Solution:

1. **Understand the Definition of Peptide Bond**:
- A peptide bond is a chemical bond formed between two amino acids when the carboxyl group of one amino acid reacts with the amino group of another, releasing a molecule of water (condensation reaction).

2. **Analyze Each Option**:
- **Option A: Polypeptide**:
- A polypeptide is a chain of amino acids linked together by peptide bonds. Therefore, peptide bonds are present in polypeptides.

- **Option B: Enzyme**:
- Enzymes are proteins that catalyze biochemical reactions. Since enzymes are made up of amino acids, they also contain peptide bonds. Thus, peptide bonds are present in enzymes.

- **Option C: Amino Acid**:
- An amino acid is the basic building block of proteins. Individual amino acids do not contain peptide bonds as they are the monomers that link together to form proteins and polypeptides. Therefore, peptide bonds are absent in free amino acids.

- **Option D: Protein**:
- Proteins are polymers made up of one or more polypeptide chains. These chains are formed by linking amino acids together through peptide bonds. Hence, peptide bonds are present in proteins.

3. **Conclusion**:
- After analyzing all the options, the only option that does not contain peptide bonds is **C: Amino Acid**.

### Final Answer:
The correct answer is **C: Amino Acid**.

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