- A Glycine
- B Alanine
- C Cysteine
- D Tyrosine
Correct answer: C. Cysteine
Explanation: Cysteine contains a thiol (-SH) group. Two cysteine residues can form a disulfide bond (-S-S-), which is important for protein tertiary structure stability.
Concept context
Carbohydrates, proteins, lipids, nucleic acids, and enzyme kinetics. Essential foundation for understanding metabolism.