Multiple Choice
Which of the following amino acids would be positively charged at physiological pH (approximately 7.4)?
16
views
3. Amino Acids
Amino Acid Groups
Struggling with Biochemistry?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Which part of an individual amino acid distinguishes it from other amino acids?
A
The central (alpha) carbon
B
The carboxyl group (\(-COOH\))
C
The side chain (R group)
D
The amino group (\(-NH_2\))
Verified step by step guidance1
Understand the structure of an amino acid: Each amino acid has a central (alpha) carbon atom bonded to four groups: a hydrogen atom, an amino group (
), a carboxyl group (
), and a side chain (R group).
Recognize that the amino group (
) and carboxyl group (
) are common to all amino acids and do not vary.
Focus on the side chain (R group): The R group is the variable part of the amino acid and determines its unique chemical properties, such as polarity, charge, and hydrophobicity.
Understand the significance of the R group: The R group can range from a simple hydrogen atom (as in glycine) to complex ring structures (as in tryptophan), and this variation is what distinguishes one amino acid from another.
Conclude that the correct answer is the side chain (R group), as it is the distinguishing feature of individual amino acids.
Related Videos
Related Practice
Amino Acid Groups practice set
Problem sets built by lead tutorsExpert video explanations