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 is true regarding protein ubiquitination?

Ubiquitin tagged proteins are usually degraded in the cell.

Ubiquitin is a ubiquitous, small nucleotide.

Covalent attachment of ubiquitin usually occurs via the R groups of methionine amino acid residues.

Ubiquitin links to the target protein only via hydrogen bonds.

Only a and c are true.

All of the above are true.

None of the above are true.

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Verified step by step guidance

Understand the role of ubiquitin in the cell: Ubiquitin is a small regulatory protein that is found in almost all tissues of eukaryotic organisms. It plays a crucial role in targeting proteins for degradation by the proteasome, a protein complex that degrades and recycles damaged or unneeded proteins.

Examine the statement 'Ubiquitin tagged proteins are usually degraded in the cell': This statement is true. The attachment of ubiquitin to a substrate protein typically signals for its degradation by the proteasome.

Analyze the statement 'Ubiquitin is a ubiquitous, small nucleotide': This statement is false. Ubiquitin is a protein, not a nucleotide. It consists of 76 amino acids and is not related to nucleotides, which are the building blocks of nucleic acids like DNA and RNA.

Evaluate the statement 'Covalent attachment of ubiquitin usually occurs via the R groups of methionine amino acid residues': This statement is false. Ubiquitin is covalently attached to lysine residues on the target protein through an isopeptide bond, not methionine.

Consider the statement 'Ubiquitin links to the target protein only via hydrogen bonds': This statement is false. The linkage between ubiquitin and the target protein is covalent, not through hydrogen bonds. The covalent bond is formed between the C-terminal glycine of ubiquitin and the epsilon amino group of a lysine residue on the substrate protein.