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Questions and Answers
Enzymes function by ____________ the activation energy needed for reactions.
Enzymes function by ____________ the activation energy needed for reactions.
Which of the following classifications accurately represents enzymes?
Which of the following classifications accurately represents enzymes?
What is the usual optimum pH range for most enzymes to function effectively?
What is the usual optimum pH range for most enzymes to function effectively?
Which of the following factors does NOT influence the rate of enzyme-catalyzed reactions?
Which of the following factors does NOT influence the rate of enzyme-catalyzed reactions?
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Enzymes are classified into how many major classes?
Enzymes are classified into how many major classes?
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Which class of enzymes is responsible for catalyzing oxidation-reduction reactions?
Which class of enzymes is responsible for catalyzing oxidation-reduction reactions?
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What type of enzyme catalyzes the addition of water to cleave bonds?
What type of enzyme catalyzes the addition of water to cleave bonds?
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Which enzyme class is NOT involved in the rearrangement of molecular structures?
Which enzyme class is NOT involved in the rearrangement of molecular structures?
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Which of the following enzyme classifications centers on the transfer of functional groups?
Which of the following enzyme classifications centers on the transfer of functional groups?
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Which enzyme class is characterized by catalyzing bond breakage without the addition of water?
Which enzyme class is characterized by catalyzing bond breakage without the addition of water?
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Enzymes used as therapeutic agents can be best classified under which category?
Enzymes used as therapeutic agents can be best classified under which category?
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What is the primary function of ligases in enzymatic reactions?
What is the primary function of ligases in enzymatic reactions?
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What is a key characteristic of isomerases?
What is a key characteristic of isomerases?
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Which of the following correctly identifies a diagnostic use of enzymes?
Which of the following correctly identifies a diagnostic use of enzymes?
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Which type of reaction would hydrolases NOT be involved in?
Which type of reaction would hydrolases NOT be involved in?
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What does a smaller Km indicate about the enzyme's affinity for its substrate?
What does a smaller Km indicate about the enzyme's affinity for its substrate?
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How does increasing cofactor concentration affect the velocity of a reaction?
How does increasing cofactor concentration affect the velocity of a reaction?
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What is the effect of inhibitor concentration on the velocity of an enzyme-catalyzed reaction?
What is the effect of inhibitor concentration on the velocity of an enzyme-catalyzed reaction?
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What happens to enzyme activity as temperature increases beyond the optimum level?
What happens to enzyme activity as temperature increases beyond the optimum level?
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What is the most favorable pH range for most enzymes?
What is the most favorable pH range for most enzymes?
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How does the passage of time generally affect the velocity of an enzyme-catalyzed reaction?
How does the passage of time generally affect the velocity of an enzyme-catalyzed reaction?
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What is the optimum temperature for enzyme activity?
What is the optimum temperature for enzyme activity?
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If the pH moves 2 units away from an enzyme's optimum pH, what is likely to happen?
If the pH moves 2 units away from an enzyme's optimum pH, what is likely to happen?
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What indicates a higher Km value for an enzyme?
What indicates a higher Km value for an enzyme?
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At which point does increasing enzyme concentration not further increase reaction velocity?
At which point does increasing enzyme concentration not further increase reaction velocity?
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What is the mechanism of enzyme action described by the induced fit model?
What is the mechanism of enzyme action described by the induced fit model?
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Which factor does NOT affect the rate of enzyme-catalyzed reactions?
Which factor does NOT affect the rate of enzyme-catalyzed reactions?
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What does the Michaelis constant (Km) indicate about an enzyme's interaction with its substrate?
What does the Michaelis constant (Km) indicate about an enzyme's interaction with its substrate?
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How does increasing substrate concentration affect an enzyme-catalyzed reaction?
How does increasing substrate concentration affect an enzyme-catalyzed reaction?
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Which of the following accurately describes an inhibitor in enzyme reactions?
Which of the following accurately describes an inhibitor in enzyme reactions?
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What occurs when an enzyme is said to be in a saturated state?
What occurs when an enzyme is said to be in a saturated state?
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Which of the following factors would most likely lead to an increase in enzyme velocity, assuming other conditions are optimal?
Which of the following factors would most likely lead to an increase in enzyme velocity, assuming other conditions are optimal?
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What relationship does the initial velocity (Vi) have with substrate concentration [S] before reaching maximum velocity (Vmax)?
What relationship does the initial velocity (Vi) have with substrate concentration [S] before reaching maximum velocity (Vmax)?
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In enzyme kinetics, which scenario illustrates a high affinity between an enzyme and its substrate?
In enzyme kinetics, which scenario illustrates a high affinity between an enzyme and its substrate?
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What is the primary role of cofactors in enzyme catalysis?
What is the primary role of cofactors in enzyme catalysis?
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What is the primary role of enzymes in biochemical reactions?
What is the primary role of enzymes in biochemical reactions?
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Which of the following statements about substrates is correct?
Which of the following statements about substrates is correct?
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What term describes the active site of an enzyme?
What term describes the active site of an enzyme?
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Which of the following is NOT a characteristic of enzymes?
Which of the following is NOT a characteristic of enzymes?
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What is the term for a conjugated enzyme?
What is the term for a conjugated enzyme?
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What are cofactors in the context of enzymes?
What are cofactors in the context of enzymes?
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Which factor does NOT typically affect enzyme activity?
Which factor does NOT typically affect enzyme activity?
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How do enzymes affect the velocity of biochemical reactions?
How do enzymes affect the velocity of biochemical reactions?
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Study Notes
Course Information
- Academic Year: 2024-2025
- Year: 1
- Semester: 1
- Module: Human Body Function (HBF) 102
Enzymes
- Enzymes are biocatalysts that regulate the speed of biochemical reactions.
- Substrates are the molecules acted upon by enzymes. Enzymes are specific to their substrates.
- Products are formed during the reaction, aided by the enzyme.
- Active site is the region of an enzyme where a substrate molecule binds, also called the catalytic site or substrate-binding site.
- An enzyme's active site has a specific shape that allows it to bind to a specific substrate molecule.
Enzyme Objectives
- Define enzymes and understand their significance in medicine.
- Categorize enzymes into six main groups.
- Identify the general characteristics of enzymes.
- Explain the mechanism of enzyme actions.
- Describe factors that impact enzyme activity and reaction rate.
- Enzyme activity is optimal at 37°C.
- Enzymes are proteins.
Enzyme Common Features
- Enzymes are made by living cells and can operate outside cells.
- They're effective in small quantities.
- They speed up reactions without affecting equilibrium.
- Enzymes aren't chemically modified after the reaction finishes.
- They have varying degrees of substrate specificity (specific substrates or related ones).
Chemical Nature of Enzymes
- Most enzymes are proteins, either simple or conjugated.
- Holoenzyme: The conjugated protein.
- Apoenzyme: The protein component.
- Cofactor: The non-protein component assists the reaction.
Enzyme Mechanism (Induced Fit Model)
- A substrate attaches to the active site.
- The active site's shape slightly changes to fit the substrate better.
- An ideal fit is generated for catalysis.
- Enzymes decrease the activation energy, required for a reaction to occur.
Factors Affecting Enzyme Activity
- Substrate concentration ([S]) — Directly proportional to the enzyme-substrate complex concentration, up to saturation.
- Enzyme concentration (E) — Reaction velocity increases with enzyme concentration; plateaus when maximum reached.
- Cofactor concentration (C) — Reaction velocity increases proportionally with cofactor concentration, up to a point.
- Inhibitor concentration (I) — Inversely proportional to reaction velocity.
- Temperature — Enzyme-catalyzed reaction rate increases with rising temperature up to an optimal temperature of 37°C. Above this, denaturation can occur.
- pH — Enzymes function best at a specific pH; activity decreases significantly above or below this optimal range (typically within 5-9).
- Time — Enzyme activity diminishes as substrates are consumed, and enzymes become inactive over time.
Enzyme Classification
- Enzymes are categorized into six classes based on the reaction type they catalyze:
- Oxidoreductases
- Transferases
- Hydrolases
- Lyases
- Isomerases
- Ligases
Biomedical Importance of Enzymes
- Diagnostic markers for tissue-specific diseases.
- Commercial diagnostic reagents for biochemical tests.
- Therapeutic agents.
- Drug targets.
Interactive Questions
- Definition of enzyme.
- List 3 factors affecting enzyme activity.
- Explain why enzyme activity stops at 70°C.
- How do enzymes speed up reactions?
- What is an enzyme made of?
- What is the optimum pH for most enzymes?
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Description
Test your knowledge on enzymes in the Human Body Function module. This quiz covers the definitions, classifications, mechanisms of action, and factors affecting enzyme activity. Dive into the crucial role enzymes play in biochemistry and medicine.
