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Questions and Answers
What is a biological catalyst?
What is a biological catalyst?
What are enzymes described as?
What are enzymes described as?
Biological catalysts
What type of enzymes operate within cells?
What type of enzymes operate within cells?
Intracellular
What type of enzymes are secreted by cells?
What type of enzymes are secreted by cells?
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What shape are enzymes typically folded into?
What shape are enzymes typically folded into?
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What is the active site of an enzyme?
What is the active site of an enzyme?
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What is a substrate?
What is a substrate?
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What is the Lock and Key Hypothesis?
What is the Lock and Key Hypothesis?
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What is the enzyme-substrate complex?
What is the enzyme-substrate complex?
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How many types of substrate molecules does an enzyme usually act on?
How many types of substrate molecules does an enzyme usually act on?
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What does the induced fit hypothesis suggest?
What does the induced fit hypothesis suggest?
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How do enzymes catalyze reactions?
How do enzymes catalyze reactions?
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What does activation energy refer to?
What does activation energy refer to?
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What is the peak of the effect of temperature on enzyme activity?
What is the peak of the effect of temperature on enzyme activity?
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What is the optimum temperature for enzyme activity in most mammals?
What is the optimum temperature for enzyme activity in most mammals?
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What happens to enzymes at extreme pH levels?
What happens to enzymes at extreme pH levels?
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What is an enzyme inhibitor?
What is an enzyme inhibitor?
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What are competitive inhibitors?
What are competitive inhibitors?
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What defines non-competitive inhibitors?
What defines non-competitive inhibitors?
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What is the turnover rate of an enzyme?
What is the turnover rate of an enzyme?
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What does the Michaelis-Menten constant (Km) measure?
What does the Michaelis-Menten constant (Km) measure?
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Study Notes
Enzymes Overview
- Biological catalysts speed up chemical reactions without being altered at the end of the process.
- Enzymes are proteins functioning as biological catalysts that enhance reaction rates.
Types of Enzymes
- Intracellular enzymes operate within cells.
- Extracellular enzymes are secreted by cells and catalyze reactions outside, such as digestive enzymes.
Enzyme Structure
- Enzymes are globular proteins with a precise three-dimensional shape, ensuring solubility.
Key Concepts
- Active site: a specific region where substrates bind to enzymes.
- Substrate: the molecule(s) that fit into the enzyme's active site.
- Lock and Key Hypothesis: suggests a specific fit between substrate and enzyme shape; modified to account for enzyme flexibility.
- Induced Fit Hypothesis: explains how enzymes and substrates adjust their shapes to enhance binding efficiency.
Reaction Mechanics
- Enzyme-substrate complex formed through temporary bonds, allowing reaction facilitation.
- Each enzyme typically acts on one substrate type, indicating specificity.
- Enzymes can catalyze reactions that involve breaking down or joining molecules.
Activation Energy
- Activation energy is the energy required to convert substrates into products; enzymes reduce this energy requirement.
Enzyme Activity Factors
- Enzyme concentration affects initial reaction rates; more enzymes lead to faster reactions if substrates are abundant.
- Substrate concentration influence: increased substrate raises reaction rates until saturation occurs at Vmax.
Temperature and pH Effects
- Reaction rates increase with temperature due to increased molecular movement, peaking at optimum levels (typically around 40°C for mammals).
- Enzymes denature (lose function) at high temperatures, negatively affecting activity.
- Most enzymes operate best at pH 7; extreme pH changes can denature enzymes.
Inhibition Mechanisms
- Enzyme inhibitors decrease enzyme activity; effects can be reversible or irreversible.
- Competitive inhibitors mimic substrates and compete for the active site, while non-competitive inhibitors bind elsewhere, altering enzyme shape.
End-Product Inhibition
- A process where a product inhibits an enzyme's function, slowing down the reaction chain while remaining reversible.
Enzyme Kinetics
- Turnover rate describes how quickly an enzyme converts substrates, estimated at around 1000 substrate molecules per second.
- The Michaelis-Menten constant (Km) indicates the substrate concentration at which the enzyme operates at half its maximum rate, reflecting enzyme affinity for substrates.
Immobilized Enzymes
- Enzymes can be attached to inert materials for reuse, providing cost advantages and increased stability against temperature and pH changes.
Affinity
- Higher affinity indicates a stronger interaction between enzyme and substrate, reflected in a lower Km value.
Reaction Rate Measurement
- The rate of reaction can be quantified by measuring the amount of product formed per unit time, providing insights into enzyme efficiency.
Studying That Suits You
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Description
Test your knowledge on enzymes with these flashcards. Each card contains key terms and their definitions, focusing on the role of enzymes as biological catalysts. Perfect for students studying biological processes and chemistry.
