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 amino acid is least likely to be found in one of the transmembrane domains of GPCR43?

Valine

Phenylalanine

Leucine

Aspartic acid

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Understand the structure of transmembrane domains in GPCRs: Transmembrane domains are typically composed of hydrophobic alpha-helices that span the lipid bilayer. These regions are rich in nonpolar, hydrophobic amino acids to interact favorably with the hydrophobic environment of the membrane.

Analyze the properties of the given amino acids: Valine, Phenylalanine, and Leucine are all nonpolar, hydrophobic amino acids, making them suitable for incorporation into transmembrane domains. Aspartic acid, however, is polar and negatively charged, which makes it hydrophilic and less likely to be found in the hydrophobic environment of the membrane.

Recall the principle of hydrophobicity: Hydrophobic amino acids are favored in transmembrane regions because they minimize unfavorable interactions with the aqueous environment. Hydrophilic amino acids, like Aspartic acid, are typically found in regions exposed to water, such as extracellular or intracellular loops.

Consider the functional role of GPCRs: GPCRs (G-protein-coupled receptors) rely on their transmembrane domains to anchor them within the lipid bilayer and facilitate signal transduction. Hydrophobic amino acids contribute to the stability and proper folding of these domains.

Conclude based on the properties of Aspartic acid: Aspartic acid's hydrophilic nature makes it least likely to be found in the transmembrane domain of GPCR43, as it would disrupt the hydrophobic environment required for proper membrane integration.