Enzymes and Their Functions

Enzyme Definition

• Biological catalysts
• Not consumed during a chemical reaction
• Essential for many biological processes
• Mostly proteins
• Highly specific, function optimally at body temperature (37°C) and physiological pH (7)
• Suffix "-ase"

Activation Energy

• The minimum energy required for a chemical reaction to start
• Catalysts reduce activation energy

Enzyme Classification

• Oxidoreductases
  • Catalyze oxidation-reduction reactions
• Transferases
  • Transfer functional groups
• Hydrolases
  • Break down molecules by adding water
• Lyases
  • Break down molecules, but don't require water
• Isomerases
  • Convert molecules into isomers
• Ligases
  • Join molecules together

Mechanism of Enzyme Action

• Binding of substrate to the enzyme's active site
• Active site is the specific area that binds to the substrate

Factors Affecting Enzyme Activity

Temperature

• Increases reaction rate, up to a point
• Beyond the optimal temperature, the enzyme denatures, and its activity decreases

pH

• Each enzyme has an optimal pH
• Deviation from the optimal pH can denature the enzyme

Enzyme Concentration

• Increased enzyme concentration leads to a higher reaction rate
• Up to a point where the substrate becomes limiting

Substrate Concentration

• Increased substrate concentration leads to a higher reaction rate
• Up to a point where the enzyme becomes saturated and the reaction rate plateaus

This quiz covers the fundamental concepts of enzymes, including their definitions, classifications, and the factors affecting their activity. Understand how enzymes function as biological catalysts, their mechanisms, and the importance of activation energy in chemical reactions.