Enzymes as Biological Catalysts: Lab Summary and Concepts

Enzyme

Biological catalyst.

Catalyst

Speeds up a chemical reaction by lowering activation energy.

Substrate

Molecule acted upon by the enzyme.

Active Site

Specific location where the substrate binds to the enzyme.

Products

Molecules produced after the reaction.

Denaturation

Change in the enzyme's 3D shape due to environmental changes (pH, temperature).

Effect of Denaturation

Distorts the active site, making the enzyme non-functional.

Substrate Concentration

Higher concentration → faster reaction.

Enzyme Concentration

Higher concentration → faster reaction.

Temperature

Enzymes have an optimal temperature for maximum activity.

pH

Enzymes have an optimal pH for maximum activity.

Allosteric Regulators

Molecules that bind to enzymes, turning them 'on' or 'off'.

Catalase

Enzyme that breaks down hydrogen peroxide (H₂O₂) into water (H₂O) and oxygen (O₂).

Catalase Reaction

2H₂O₂ → 2H₂O + O₂.

Effect of Boiling on Inorganic Catalyst

Boiling increases activity (more O₂ bubbles).

Effect of Boiling on Organic Catalyst

Boiling denatures the enzyme (no O₂ bubbles).

Lactase

Enzyme that breaks down lactose into glucose and galactose.

Lactose

Disaccharide (glucose + galactose).

Sucrose

Disaccharide (glucose + fructose).

Lactase Specificity Conclusion

Lactase is specific to lactose due to the shape of the active site.

Hydrolysis

Breaks down lactose into glucose and galactose.

Optimal Temperature for Lactase

Body Temperature (37°C): Where lactase functions best.

Purpose of Potato

Source of catalase. Prepared by grinding and extracting the enzyme.

Purpose of Test Strips

Detect glucose. Only Tube B (lactose + lactase) tested positive.