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

Alanine and leucine are examples of ______ amino acids.

polar

nonpolar

acidic

basic

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Verified step by step guidance

Step 1: Begin by understanding the classification of amino acids based on their side chain properties. Amino acids can be categorized as polar, nonpolar, acidic, or basic depending on the chemical nature of their R-group (side chain).

Step 2: Examine the structures of alanine and leucine. Alanine has a methyl group (-CH3) as its side chain, and leucine has an isobutyl group (-CH2-CH-(CH3)2) as its side chain. Both of these side chains consist entirely of hydrocarbons, which are hydrophobic and lack polar functional groups.

Step 3: Recall that nonpolar amino acids have side chains that are hydrophobic and do not interact favorably with water. Since alanine and leucine have hydrocarbon side chains, they fall into the category of nonpolar amino acids.

Step 4: Eliminate the other options. Polar amino acids have side chains with groups that can form hydrogen bonds (e.g., hydroxyl, amide, or sulfhydryl groups). Acidic amino acids have negatively charged side chains at physiological pH (e.g., aspartate and glutamate), and basic amino acids have positively charged side chains (e.g., lysine, arginine, and histidine). Alanine and leucine do not fit these descriptions.

Step 5: Conclude that alanine and leucine are examples of nonpolar amino acids based on their hydrophobic side chains.