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 statements about amino acids is true?

All amino acids have a carboxyl group and an amino group attached to the same carbon atom.

The side chain (R group) of all amino acids is identical.

All amino acids are nonpolar at physiological pH.

Amino acids do not contain chiral centers.

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Verified step by step guidance

Step 1: Begin by understanding the structure of amino acids. Amino acids are the building blocks of proteins and consist of a central carbon atom (called the alpha carbon) to which four groups are attached: a carboxyl group (-COOH), an amino group (-NH2), a hydrogen atom, and a variable side chain (R group).

Step 2: Evaluate the first statement: 'All amino acids have a carboxyl group and an amino group attached to the same carbon atom.' This is true for standard amino acids, as the carboxyl and amino groups are both attached to the alpha carbon.

Step 3: Evaluate the second statement: 'The side chain (R group) of all amino acids is identical.' This is false because the R group varies among amino acids and determines their unique properties, such as polarity, charge, and hydrophobicity.

Step 4: Evaluate the third statement: 'All amino acids are nonpolar at physiological pH.' This is incorrect because amino acids can be polar, nonpolar, acidic, or basic depending on the nature of their R group. For example, glutamate is acidic, while lysine is basic.

Step 5: Evaluate the fourth statement: 'Amino acids do not contain chiral centers.' This is false because most amino acids (except glycine) have a chiral alpha carbon, meaning they exist in L- and D- stereoisomers. The L-form is predominant in biological systems.