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 of the following best describes the action of an EcoRI/PstI enzyme mixture on a DNA sample?

It ligates DNA fragments together at EcoRI and PstI sites, forming recombinant DNA.

It cuts DNA at specific recognition sites for both EcoRI and PstI, generating fragments with different sticky ends.

It methylates DNA at the recognition sites for EcoRI and PstI, protecting the DNA from cleavage.

It denatures DNA, separating the two strands at EcoRI and PstI sites.

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Verified step by step guidance

Step 1: Understand the function of restriction enzymes like EcoRI and PstI. These enzymes are endonucleases that recognize specific DNA sequences and cleave the DNA at those sites. EcoRI recognizes the sequence GAATTC, while PstI recognizes CTGCAG.

Step 2: Learn about the concept of 'sticky ends.' When EcoRI and PstI cut DNA, they leave overhanging sequences (sticky ends) that can pair with complementary sequences, facilitating the joining of DNA fragments.

Step 3: Clarify that restriction enzymes do not ligate DNA fragments. Ligases are separate enzymes responsible for joining DNA fragments by forming phosphodiester bonds.

Step 4: Note that restriction enzymes do not methylate DNA. Methylation is performed by methyltransferases, which add methyl groups to protect DNA from cleavage by restriction enzymes.

Step 5: Understand that restriction enzymes do not denature DNA. Denaturation involves separating the two strands of DNA, typically by heat or chemical agents, not by enzymatic cleavage.