Variation in proteins due to

Options

A. sequence of amino acids
B. number of amino acids
C. R-groups
D. none

Answer

### Step-by-Step Solution:

1. **Understanding Proteins**:
- Proteins are large biomolecules made up of smaller units called amino acids. They play crucial roles in the body, including structural, functional, and regulatory roles.

2. **Amino Acids and Peptide Bonds**:
- Proteins are polymers formed by the linkage of amino acids through peptide bonds. The sequence in which these amino acids are arranged is critical for the protein's function.

3. **Sequence of Amino Acids**:
- The variation in proteins primarily arises from the sequence of amino acids. Different sequences lead to different protein structures and functions.

4. **Genetic Code**:
- The sequence of amino acids in a protein is determined by the sequence of nucleotides in DNA. This information is transcribed into messenger RNA (mRNA) during the process of transcription.

5. **Translation Process**:
- During translation, the mRNA is read by ribosomes, and the corresponding amino acids are assembled in the order specified by the mRNA sequence, resulting in a specific protein.

6. **Conclusion**:
- Therefore, the variation in proteins is due to the sequence of amino acids, which is dictated by the genetic code in DNA. Other factors like the number of amino acids or the R groups (side chains) do not independently cause variation in proteins.

### Final Answer:
The variation in proteins is due to the **sequence of amino acids**.

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