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

7. Enzyme Inhibition and Regulation

Ubiquitination

Biochemistry

7. Enzyme Inhibition and Regulation

Ubiquitination

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Multiple Choice

Which of the following statements about ubiquitin is TRUE?

Ubiquitin is a lipid molecule involved in membrane synthesis.

Ubiquitin is a carbohydrate that serves as an energy source for cells.

Ubiquitin acts as an enzyme that catalyzes phosphorylation reactions.

Ubiquitin is a small protein that tags other proteins for degradation by the proteasome.

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Verified step by step guidance

Step 1: Begin by understanding what ubiquitin is. Ubiquitin is a small regulatory protein found in eukaryotic cells. It plays a critical role in tagging proteins for degradation, ensuring proper protein turnover and cellular homeostasis.

Step 2: Evaluate the incorrect options one by one. The first option states that ubiquitin is a lipid molecule involved in membrane synthesis. This is incorrect because ubiquitin is a protein, not a lipid, and it is not involved in membrane synthesis.

Step 3: Analyze the second option, which claims ubiquitin is a carbohydrate that serves as an energy source for cells. This is also incorrect because ubiquitin is not a carbohydrate and does not function as an energy source.

Step 4: Examine the third option, which suggests ubiquitin acts as an enzyme that catalyzes phosphorylation reactions. This is incorrect because ubiquitin is not an enzyme and does not catalyze phosphorylation reactions. Instead, it tags proteins for degradation.

Step 5: Confirm the correct answer. Ubiquitin is a small protein that tags other proteins for degradation by the proteasome. This process is known as ubiquitination, and it involves the covalent attachment of ubiquitin to target proteins, marking them for breakdown in the proteasome.