Enzymes

Question 1

What are enzymes?

Answer 1

Biological catalysts that control reactions in the body. Each enzyme is specific.

Question 2

What happens to the molecules at different temperatures?

Answer 2

• at lower temps the molecules move more slowly so substrate molecules take longer to fit into and react with the active site.
• at the optimum temp the enzyme is working at its fastest rate.
• higher temps cause the active site to change shape so it cant bind to the substrate as tightly so the reaction goes more slowly.
• at very high temps the active site breaks up and the enzyme is denatured.

Question 3

What is the Ph and enzyme activity core practical?

Answer 3

Aim:
to investigate the effect of pH on amylase activity.

Method:
- add amylase to a buffered starch solution in a test tube.

• place the tube in a water bath at a constant temperature.
• take samples of the mixture at regular intervals and mix them with a fresh drop of iodine in a dimple tile.
• repeat the test until the iodine stops changing colour when the starch mixture is added. Record the time taken for this to happen.
• Repeat the procedure at different pH values.

Question 4

What do enzymes do to the rate of reaction?

Answer 4

Speed up the rate of reaction but are not used up in the reaction. This means they can be used over and over again.

Question 5

What are uses of food molecules?

Answer 5

Carbohydrates=
e.g. starch for energy storage in plants.

Sugars=
e.g. glucose for respiration.

Lipids=
for energy storage.

Fatty acids + Glycerol=
for respiration.

Proteins=
for muscle cells.

Amino acids=
to make enzymes.