The enormous diversity of protein molecules is due mostly to the diversity of :

Options

A. amino groups on the amino acids
B. R groups on the amino acids
C. amino acid sequences within protein molecules
D. peptide bonds

Explanation

To solve the question "The enormous diversity of protein molecules is due mostly to the diversity of:", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Proteins**:
- Proteins are large biomolecules made up of long chains of amino acids. They play crucial roles in biological processes, including acting as enzymes, hormones, and transport molecules.

2. **Structure of Proteins**:
- Proteins are formed by polypeptide chains, which are sequences of amino acids linked together by peptide bonds.

3. **Amino Acids**:
- There are 20 standard amino acids that can be combined in various sequences to form different proteins. The specific sequence of these amino acids determines the structure and function of the protein.

4. **Diversity of Proteins**:
- The diversity of proteins arises primarily from the different sequences of amino acids. Even a small change in the sequence can lead to a completely different protein with a different function.

5. **Analyzing the Options**:
- The question asks for what contributes to the diversity of proteins.
- Options like "amino group," "R group on the amino acid," and "peptide bond" refer to specific components or types of bonds in amino acids but do not account for the overall diversity of proteins.
- The correct answer is the "amino acid sequences" because it is the variation in the order and combination of these amino acids that leads to the vast array of protein structures and functions.

### Conclusion:
The enormous diversity of protein molecules is due mostly to the diversity of **amino acid sequences within protein molecules**.

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