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

6. Enzymes and Enzyme Kinetics

Enzymes

Biochemistry

6. Enzymes and Enzyme Kinetics

Enzymes

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Multiple Choice

Which enzyme is responsible for covalently attaching methyl groups to DNA?

DNA methyltransferase

Topoisomerase

DNA ligase

DNA polymerase

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Verified step by step guidance

Understand the role of methylation in DNA: Methylation involves the addition of methyl groups (-CH₃) to specific bases in DNA, typically cytosine residues in CpG sites. This process is crucial for regulating gene expression and maintaining epigenetic marks.

Identify the enzyme responsible for methylation: The enzyme that catalyzes the transfer of methyl groups to DNA is known as DNA methyltransferase. It uses S-adenosylmethionine (SAM) as the methyl donor.

Differentiate between the given options: Topoisomerase is involved in relieving supercoiling in DNA during replication or transcription. DNA ligase is responsible for joining DNA strands by forming phosphodiester bonds. DNA polymerase synthesizes new DNA strands during replication. None of these enzymes are involved in methylation.

Focus on DNA methyltransferase: DNA methyltransferase specifically recognizes target sequences in DNA and covalently attaches methyl groups to cytosine bases, altering the DNA's epigenetic state.

Conclude that DNA methyltransferase is the correct answer: Based on its function in methylation, DNA methyltransferase is the enzyme responsible for covalently attaching methyl groups to DNA.