A student examines the structure of a generic amino acid. The teacher explains that 20 different amino acids share three common groups but differ in only one part. Identifying that part is critical for understanding why some amino acids are hydrophobic while others are charged or polar.
Which group in the diagram is responsible for the chemical diversity that distinguishes one amino acid from another?
- A
Amino group (blue)
- Bcheck_circle
R group (orange)
- C
Alpha hydrogen (green)
- D
Carboxyl group (red)
Explanation
All 20 standard amino acids share NH2, COOH, H, and a central C-alpha; only the R (side chain) varies, dictating polarity, charge, and chemistry.