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 amino acids is classified as a basic amino acid?

Aspartic acid

Lysine

Serine

Valine

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Verified step by step guidance

Step 1: Understand the classification of amino acids based on their side chain properties. Amino acids can be categorized as acidic, basic, polar, or nonpolar depending on the chemical nature of their R-group (side chain). Basic amino acids have positively charged side chains at physiological pH.

Step 2: Recall the structures of the amino acids listed in the problem. Aspartic acid has a negatively charged carboxyl group in its side chain, making it acidic. Serine has a hydroxyl group, making it polar but not basic. Valine has a nonpolar, hydrophobic side chain. Lysine has an amino group in its side chain, which is positively charged at physiological pH, classifying it as a basic amino acid.

Step 3: Compare the side chains of the amino acids provided. Identify which amino acid has a positively charged group at physiological pH, as this is the defining characteristic of basic amino acids.

Step 4: Confirm that Lysine is the correct answer because its side chain contains an amino group (-NH3+) that is protonated and positively charged at physiological pH, fitting the definition of a basic amino acid.

Step 5: Conclude that Aspartic acid, Serine, and Valine do not meet the criteria for basic amino acids based on their side chain properties, while Lysine does.