Enzyme Function and Mechanism Quiz

Enzyme Function

• Enzymes are biological catalysts that accelerate biochemical reactions.
• Without enzymes, many reactions would take millions of years.
• Enzymes reduce reaction times to milliseconds.
• They are crucial for sustaining life's biological functions (growth, reproduction, homeostasis).
• Enzymes increase reaction rates to biologically relevant levels.
• Enzymes lower activation energy, the minimum energy required for a reaction to occur spontaneously.
• Enzymes don't alter the overall energy (Gibbs free energy) of a reaction; they only lower the activation energy needed to start it.

Enzyme Mechanism

• Enzymes function by bringing reactants (substrates) together for efficient interaction.
• The main function of enzymes is to lower activation energy, enabling reactions to proceed at life-sustaining rates.
• Some enzymes require cofactors (ions, vitamins, or organic groups) to function properly. These cofactors help maintain the enzyme's 3D shape and substrate binding.
• Enzyme function involves four steps: substrate and enzyme availability, binding at the active site forming an enzyme-substrate complex, product formation, and product release.
• Enzymes are not changed during the reaction, allowing them to catalyze multiple reactions.

Enzyme Structure and Active Site

• Enzymes are proteins with a specific 3D tertiary structure.
• The active site is the region where the substrate binds to the enzyme.
• Substrate binding induces a conformational change in the enzyme, facilitating product formation.
• Lactase, which breaks down lactose (milk sugar) into glucose and galactose is an example of an enzyme in humans
• The active site facilitates the conversion of substrate to product.
• Two models describe substrate-enzyme interaction: induced fit (enzyme changes shape to bind substrate) and lock and key (substrate fits directly into the enzyme).