1. What do the enzymes in the washing powder do?

2. Why does it say to wash at 40 oC?

8A6 Enzymes

What are enzymes?

• Enzymes are proteins made by cells• Enzymes are biological catalysts

• When enzymes are denatured they stop working.• Denatured means that they lose their ability to do

their job properly.• Enzymes can become denatured when:

- the temperature gets too high (human enzymes work best at 37 C).

- the surroundings are too acid or alkaline.

Denatured enzymes

Digestive enzymes work best at certain pH values.

Ideal conditions

Amylase prefers alkaline conditions.

Proteases in the stomach prefer acid.

Enzymes in the small intestine prefer alkaline conditions.

• How can you show that amylase is breaking down starch?

• How will you know when starch has been broken down?• What variables may affect how quickly the reaction

happens?• How will you measure and control the variables?• What quantities of materials will you need?• What equipment will you need?• How will you make sure your investigation is safe?

Enzyme investigation

Think about these things before you start the investigation.

ProductEnzymeFood

glucose

lipase amylase

protease

fatty acids

protein

starch

amino acidsfat

Which food, which enzyme, which product?

Click to reveal the answers.

proteaseprotein amino acids

fat lipase fatty acids

starch amylase glucose