2.4.3 Enzyme Activity: pH

Question 1

How do enzymes denature with high or low pH

Answer 1

• Hydrogen and ionic bonds hold tertiary structure of enzyme together
• In excess H+ or OH- ions these bonds can break
• Altering shape of active stie
• So enzyme substrate complexes form less easily
• And eventually no enzyme substrate complexes can form
• So the enzyme is denatured

Question 2

Investigating the effect of pH on enzyme reaction rates

Answer 2

• Amylase breaks down starch
• Iodine tests for starch

Question 3

Controls of experiment

Answer 3

• Equal conc and vol of enzyme used
• Equal vol and conc of starch used
• Equal time between adding iodine solution
• Control temperature
• Use a colorimeter to measure reaction more accurately