Enzymes Flashcards

Flashcards covering the topic of Enzymes, including their structure, function, and factors affecting their activity.

Enzymes

Control the metabolism of the cell by acting as biological catalysts that facilitate chemical reactions by lowering the activation energy.

Active Site

Part of an enzyme that specifically interacts with substrate molecules, requiring shape and charge compatibility for a reaction to occur.

Enzyme-Mediated Chemical Reaction

Requires the shape and charge of the substrate to be compatible with the active site of the enzyme.

Denaturation

Occurs when the protein structure of an enzyme is disrupted, eliminating its ability to catalyse reactions; may be caused by environmental temperatures and pH outside the optimal range.

Enzyme Activity

Affected by environmental pH, which can disrupt hydrogen bonds that provide enzyme structure.

Enzymatic Reaction Efficiency

Determined by the relative concentration of substrates and products.

Enzyme Reaction Rate

Increased by higher environmental temperatures due to increased frequency of collisions between enzymes and substrates.

Competitive Inhibitor

Molecule that binds reversibly or irreversibly to the active site of the enzyme.

Noncompetitive Inhibitor

Molecule that binds to allosteric sites, changing the activity of the enzyme.

Activation Energy

The minimum amount of energy required for chemical reactions to start; enzymes lower this energy requirement.

Enzymes role in reactions

Increase the rate of reaction by lowering the activation energy and creating new pathways for the reaction.

Enzyme Sensitivity

Sensitive to temperature and pH, substrate-specific, work in both directions (catabolism and anabolism), and remain unchanged from the reaction they catalyse.

Active Site Function

Binds to a substrate, where bonds are broken/formed, resulting in new products; its shape and chemical environment are important.

Enzyme Specificity

An enzyme can only bind with specific substrates, determined by the shape and chemical environment of the active site.

Catalase

Enzyme that converts Hydrogen Peroxide (H2O2) into Oxygen and water (O2 + H2O).

Enzyme Ending

Enzyme names often end in '-ase' and are named after their substrate.

Lock and Key Hypothesis

Explains substrate specificity. Substrate fits perfectly into the active site.

Induced Fit Hypothesis

Explains substrate specificity. Active site changes shape to better fit the substrate.

Enzyme reactions environment

Typically occur in aqueous solutions (e.g. cytoplasm, interstitial fluid).

Enzyme Inhibitor

A molecule that disrupts the normal reaction pathway between an enzyme and a substrate.

Competitive Inhibition

Involves a molecule, other than the substrate, binding to the enzyme’s active site.

Non-competitive Inhibition

Involves a molecule binding to a site other than the active site (an allosteric site), which causes a conformational change to the enzyme’s active site.

Denaturation effect

The active site is distorted and the substrate no longer fits, caused by extreme pH and high temperatures.

Renaturation

In many cases, denaturation is reversible. Proteins can regain their native state by folding back to the original conformation once the denaturing influence is removed.