Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

3. Amino Acids

Amino Acid Groups

Biochemistry

3. Amino Acids

Amino Acid Groups

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Multiple Choice

Which of the following best describes the type of molecule tryptophan is?

Sulfur-containing amino acid

Aromatic amino acid

Aliphatic amino acid

Basic amino acid

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Verified step by step guidance

Understand the structure of tryptophan: Tryptophan is an amino acid with a side chain that contains an indole group, which is a bicyclic structure consisting of a benzene ring fused to a pyrrole ring.

Classify the side chain: The indole group in tryptophan is aromatic because it contains conjugated π-electrons that follow Huckel's rule for aromaticity (4n+2 π-electrons, where n is an integer).

Compare tryptophan's side chain to the options: Sulfur-containing amino acids, such as cysteine and methionine, have sulfur atoms in their side chains, which tryptophan does not. Aliphatic amino acids, such as alanine and leucine, have non-aromatic hydrocarbon side chains. Basic amino acids, such as lysine and arginine, have positively charged side chains at physiological pH, which tryptophan does not.

Identify the correct classification: Since tryptophan's side chain is aromatic due to the indole group, it is classified as an aromatic amino acid.

Conclude the reasoning: Based on the structural and chemical properties of tryptophan, the correct answer is 'Aromatic amino acid'.