Enzymes

Question 1

What is enzyme activity?

Answer 1

• Enzyme activity is the rate at which enzymes catalyse reactions to produce products (how quickly they are working)
• Higher activity = products forming faster

Question 2

What are factors that affect enzyme activity? #1

Answer 2

1. Concentration of reactants (substrate)
   - More substrate = increased rate of reaction
   - More substrate in contact with enzyme
   - Saturation reached when all enzymes are being used
   - Can only increase again if enzyme concentration increases

Question 3

What are factors that affect enzyme activity? #2

Answer 3

2. Concentration of products
   - Must be continually removed otherwise rate of reaction will slow
   - Build up of products makes it difficult for substrate to make contact with the enzyme

Question 4

What are factors that affect enzyme activity? #3

Answer 4

3. Temperature
   - Increased temp = increased activity
   - If too high (past optimal temp) it denatures the enzyme
   - Temp too low = decreased activity

Question 5

What are factors that affect enzyme activity? #4

Answer 5

4. pH
   - Each enzyme has an optimum pH
   - Optimum pH increases activity

Question 6

What are factors that affect enzyme activity? #5

Answer 6

5. Co- factors & Co- enzymes
   - Molecules required to activate enzyme
   - Cofactors change the shape of the active site so the enzyme can combine with the substrate
   - Co- factors = ions, non- protein molecules
   - Co- enzymes = non- protein organic molecules, vitamins

Question 7

What are factors that affect enzyme activity? #6

Answer 7

6. Enzyme inhibitors
   - Substances that slow/ stop enzyme activity
   - May be used to control reactions so products are produced in certain amounts
   - Some drugs are enzyme inhibitors

Question 8

Denaturing enzymes

Answer 8

• The active site is the specific portion an enzyme that attaches to the substrate
• The specific shape of the active site must be maintained if the protein is to function properly
• Extreme temperatures or pH levels outside of the optimum range can disrupt the internal chemical bonds of the enzyme, causing the shape of the active site to change- leaving it unable to bind to substrate and function

Question 9

What are examples of digestive enzymes?

Answer 9

-Amylase is a digestive enzyme that acts on starch in food, breaking it down into smaller carbohydrate molecules
–> Produced in salivary glands and pancreas
- Protease are enzymes that breaks down protein into amino acids
–> Produced in the stomach and pancreas
- Lipase is an enzyme that breaks down dietary fats into smaller molecules called fatty acids and glycerol
–> Produced in liver and pancreas