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Questions and Answers
What primary role do enzymes play in biological systems?
What primary role do enzymes play in biological systems?
Which of the following best describes enzymes?
Which of the following best describes enzymes?
In the context of enzymatic reactions, what does 'exergonic' mean?
In the context of enzymatic reactions, what does 'exergonic' mean?
Which macromolecule, besides proteins, is mentioned as having catalytic properties?
Which macromolecule, besides proteins, is mentioned as having catalytic properties?
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What is the significance of reaction rate in biological processes?
What is the significance of reaction rate in biological processes?
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What factor is essential for enzymes to perform their catalytic function?
What factor is essential for enzymes to perform their catalytic function?
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Study Notes
Enzymes: Catalysts
- Enzymes are proteins that act as biological catalysts, increasing reaction rates for biochemical processes.
- Unlike other catalysts, many enzymes are proteins.
- They speed up reactions by lowering the activation energy (Ea).
- Small Ea values correspond to fast reactions.
- Large Ea values correspond to slow reactions.
Enzyme Activity
- Enzymes increase reaction rates by decreasing activation energy.
- Enzymes don't change the overall thermodynamics of a reaction (like the change in free energy; ΔG).
- They don't change spontaneity or equilibrium.
Effect of Enzymes on Reaction Rates
- Enzymes affect reaction kinetics, not thermodynamics.
- Enzymes speed up reactions without being consumed or altered permanently.
- Enzymes may temporarily form transient bonds during catalysis but these bonds must break by the end of the reaction so the enzyme can catalyze additional reactions.
- Enzymes catalyze both forward and reverse reactions, decreasing Ea for both.
Energetic Coupling
- Cells use enzymes to drive endergonic (nonspontaneous) reactions by coupling them with exergonic (spontaneous) reactions.
- In peptide bond formation, enzymes couple it with the hydrolysis of nucleoside triphosphates (NTPs) (often GTP).
Reversible vs. Irreversible Reactions
- Reversible reactions have a ΔG near 0 kJ/mol.
- Irreversible reactions have a large, negative ΔG.
- Small changes in reactant or product concentrations can alter the direction of a reversible reaction, but a spontaneous and irreversible reaction is unlikely to change direction.
- Enzymes catalyze both reversible and irreversible reactions.
Enzyme Behavior
- Enzyme activity relies on interactions between the active site and substrate.
- Enzymes are not consumed by reactions.
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Description
This quiz explores the role of enzymes as catalysts in biochemical reactions. Learn how enzymes increase reaction rates by lowering activation energy and their effect on reaction kinetics. Test your understanding of enzyme activity and their unique properties in catalyzing reactions.
