Unit Two: Enzymes

Question 1

What are enzymes? (2)

Answer 1

• Proteins that are made up of chains of amino acids

* Catalysts produced by living things

Question 2

What is a catalyst?

Answer 2

A substance which increased the speed of a reaction without changed or used up in the reaction

Question 3

How is an enzyme denatured?

Answer 3

When the temperature gets too hot, resulting in some of the bonds breaking and destroying the enzyme’s special shape

Question 4

At what temperature do enzymes work best at?

Answer 4

37 degrees

Question 5

What two things can denature enzymes?

Answer 5

Temperature and pH

Question 6

At what pH do enzymes work best at?

Answer 6

Neutral pH 7 (usually)

Question 7

What does amylase do?

Where is it made?

Answer 7

• It converts starch into sugars

* The salivary glands, the pancreas, the small intestine

Question 8

What does protease do?

Where is it made?

Answer 8

• It converts proteins into amino acids

* The stomach (called pepsin there), the pancreas, the small intestine

Question 9

What does lipase do?

Where is it made?

Answer 9

• It converts lipids into glycerol and fatty acids

* The pancreas and the small intestine

Question 10

What does bile do?
Where is it made?
Where is it stored?

Answer 10

• It neutralises the stomach acid and emulsified fats
• The liver
• The gall bladder

Question 11

Name some uses of enzymes

Answer 11

Used in: biological detergents, foods and industry

Question 12

Enzymes in biological detergents:

Answer 12

• Used in biological detergents and washing powders
• They’re mainly protein digesting enzymes (proteases) and fat digesting enzymes (lipases)
• The enzymes break down animal and plant matter, they’re ideal for removing stains
• More effective at working at low temperatures (e.g. 30 degrees)

Question 13

Enzymes in changing foods:

Answer 13

• Used to pre-digest baby foods using protein-digesting enzymes (proteases)
• Used to turn starch syrup into sugar syrup using carbohydrate-digesting enzymes (carbohydrases)
• Used to turn glucose syrup into fructose syrup using an isomerase enzyme (fructose is sweeter, so you can use less-good for slimming foods and drinks)

Question 14

Enzymes in industry (advantages/disadvantages)

Answer 14

•Used to speed up reactions without the need for high temperatures and pressures

Advantages:
•They’re specific
•Lower temps/pressures=lower cost/less energy used
•Enzymes work for a long time (can use continuously)
•They are biodegradable=less environmental pollution

Disadvantages:
•People can develop allergies to the enzymes
•Can be expensive to produce
•Contamination with other substances can affect the reaction
•Enzymes can be denatured by a small increase in temp