Enzymes

Question 1

Enzyme

Answer 1

An enzyme is a protein that acts as a biological catalyst to speed up chemical reactions inside a cell.

Question 2

How enzymes work:1

Answer 2

Any molecule that binds to an enzyme is called its substrate.
Enzymes bind their substrate through a specifically shaped region called the active site.
This way, each enzyme only binds its specific substrate, so can only catalyse one type of reaction.

Question 3

How enzymes work:2

Answer 3

Enzymes speed up chemical reactions by binding to molecules.
Once bound, they can break the molecule into smaller pieces by breaking chemical bonds (e.g. starch  glucose).

Question 4

Enzyme denaturation

Answer 4

Enzymes work best in certain conditions (i.e. temperature, pH).
Outside the optimum conditions (high heat, extreme pH levels), the protein will change shape.
This also causes a permanent change to the shape of the active site, preventing it from binding to the substrate.

Question 5

Factors affecting enzymes

Answer 5

Temperature
pH
Surface area

Question 6

Digestive enzymes

Answer 6

Amylase - breaks down carbohydrates in the mouth and small intestine:
Carbohydrates → Glucose

Pepsin - breaks down proteins in the stomach:
Proteins → Amino acids

Lipase - breaks down lipids in the small intestine:
Fats → Glycerol + fatty acids