Multiple Choice
Which functional groups are present in the chemical structure of every standard amino acid?
14
views
3. Amino Acids
Amino Acid Groups
Multiple Choice
In a standard amino acid, what does the R group represent?
A
The alpha hydrogen atom attached to the central carbon and responsible for chirality
B
The carboxyl group (typically deprotonated in solution) that donates a proton
C
The variable side chain that differs among amino acids and largely determines their chemical properties
D
The amino group (typically protonated in solution) that forms peptide bonds
Verified step by step guidance1
Identify the structure of a standard amino acid, which consists of a central (alpha) carbon atom bonded to four different groups: an amino group, a carboxyl group, a hydrogen atom, and an R group.
Understand that the amino group (–NH3^+) is typically protonated in physiological conditions and participates in forming peptide bonds during protein synthesis.
Recognize that the carboxyl group (–COO^-) is usually deprotonated in solution and can donate a proton, contributing to the amino acid's acidic properties.
Note that the alpha hydrogen atom is attached to the central carbon and is important for the molecule's chirality, but it is not the R group.
Conclude that the R group represents the variable side chain unique to each amino acid, which determines its chemical properties such as polarity, charge, and reactivity.
Related Videos
Related Practice
