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

An enzyme is considered a ______ because it speeds up chemical reactions without being used up.

catalyst

inhibitor

substrate

cofactor

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Verified step by step guidance

Step 1: Begin by understanding the role of an enzyme in biochemical reactions. Enzymes are proteins that act as biological catalysts, meaning they speed up chemical reactions without being consumed in the process.

Step 2: Review the definitions of the given options: 'catalyst,' 'inhibitor,' 'substrate,' and 'cofactor.' A catalyst is a substance that increases the rate of a chemical reaction without undergoing permanent change. An inhibitor slows down or stops a reaction. A substrate is the molecule upon which an enzyme acts. A cofactor is a non-protein molecule or ion required for enzyme activity.

Step 3: Compare the definition of 'catalyst' with the description of an enzyme in the problem. Enzymes fit the definition of a catalyst because they accelerate reactions without being used up.

Step 4: Eliminate the other options based on their definitions. An inhibitor does not speed up reactions; it slows them down. A substrate is the reactant in the reaction, not the enzyme itself. A cofactor assists enzymes but is not the enzyme itself.

Step 5: Conclude that the correct answer is 'catalyst,' as it aligns with the description of an enzyme provided in the problem.