Enzymes

Question 1

What are protein molecules made up of?

Answer 1

Long chains of small units called amino acids.

Question 2

What do proteins act as?

Answer 2

Structural components such as muscles and tendons. Hormones such as insulin. Antibodies, which destroy pathogens. Catalysts in the form of enzymes.

Question 3

What are enzymes?

Answer 3

Biological catalysts.

Question 4

What is a catalyst?

Answer 4

A substance which increases the rate of a reaction without being changed or used up in the reaction.

Question 5

What needs to fit in order for the reaction to be catalysed?

Answer 5

The substrate has to fit the enzyme.

Question 6

What are enzymes involved in?

Answer 6

Building large molecules from lots of smaller ones. Changing one molecule into another. Breaking down large molecules into smaller ones.

Question 7

How do enzymes work?

Answer 7

The substrate of the reaction fits into the active site of the enzyme.

Question 8

What happens when enzymes are overheated?

Answer 8

The long amino acid structure begins to denature. It can no longer act as a catalyst, so the rate of the reaction drops dramatically.

Question 9

What temperature do enzymes work best at in the human body?

Answer 9

37C

Question 10

What happens if the pH is too high or low in the body?

Answer 10

The pH interferes with the bonds holding the enzyme together. This changes the shape and denatures the enzyme.

Question 11

What is pepsins ideal pH and why?

Answer 11

2 as it works in acidic conditions in the stomach.

Question 12

Why do starch, proteins and fats needed to be broken down?

Answer 12

They’re too big to pass through the walls of the digestive system.

Question 13

What does amylase do?

Answer 13

Convert starch into sugars.

Question 14

Where is amylase made?

Answer 14

Salivary glands, pancreas and small intestine.

Question 15

What does protease do?

Answer 15

Convert proteins into amino acids.

Question 16

Where is protease made?

Answer 16

Stomach (pepsin), pancreas and small intestine.

Question 17

What does lipase do?

Answer 17

Break down lipids into fatty acids and glycerol.

Question 18

What does the acid in the stomach do?

Answer 18

Allows the protease enzymes to work very effectively.

Question 19

Where is bile stored?

Answer 19

In the gall bladder.

Question 20

Why is bile needed?

Answer 20

HCL in the stomach makes the pH too acidic for enzymes in the small intestine so it neutralises the acid and makes the conditions alkaline.

Question 21

What else does bile do?

Answer 21

It emulsifies the fats, it physically breaks up large drops of fat into smaller ones.

Question 22

What does the larger surface from the bile help to do?

Answer 22

The larger surface are helps the lipase chemically break down the fats more quickly into fatty acids and glycerol.

Question 23

Overall what dpes bile do?

Answer 23

Bile emulsifies fat droplets to increase the surface area, which in turn increases the rate of fat digestion by lipase.

Question 24

How are the salivary glands involved in digestion?

Answer 24

They produce amylase enzyme in the saliva.

Question 25

How is the liver involved in digestion?

Answer 25

Where bile is produced. Bile neutralises stomach acid and emulsifies fats.

Question 26

How is the gall bladder involved in digestion?

Answer 26

Where bile is stored before it's released into the small intestine.

Question 27

How is the large intestine involved in digestion?

Answer 27

Where excess water is absorbed from the food.

Question 28

How is the rectum involved in digestion?

Answer 28

Where the faeces are stored before they are released through the anus.

Question 29

How is the stomach involved in digestion?

Answer 29

It pummels the food with its muscular walls. It produces the protease enzyme, pepsin. It produces HCl.

Question 30

Why is HCl needed in the stomach?

Answer 30

To kill bacteria, to give the right pH for the protease enzymes to work. (pH 2)

Question 31

How is the pancreas involved in digestion?

Answer 31

Produces protease, amylase and lipase enzymes. It releases these into the small intestine.

Question 32

How is the small intestine involved in digestion?

Answer 32

Produces protease, amylase and lipase enzymes to complete digestion. Also where the digested food is absorbed out of the digestive system into the blood.

Question 33

What is used in biological detergents?

Answer 33

Protease and lipases as they break down the proteins and fats in the stains.

Question 34

What is the advantage of biological detergents?

Answer 34

They work better at lower temperatures and therefore save energy.

Question 35

Why is protease used in baby food?

Answer 35

It predigests the food as babies cannot digest solid food very well.

Question 36

What does isomerase do?

Answer 36

Used to change glucose syrup into fructose syrup.

Question 37

Why is fructose used in slimming products?

Answer 37

It is much sweeter than glucose and so smaller amounts are needed to make foods taste sweet.

Question 38

Why do carbohydrases do?

Answer 38

They can be used to turn starch syrup into sugar syrup.

Question 39

What are the advantages of using enzymes in industry?

Answer 39

They're specific and only catalyse the reaction you want them to. Using lower temperatures and pressure means a lower cost and saves energy. Enzymes work for a long time, so after the initial cost you can continually use them. They are biodegradable and therefore cause less environmental pollution.

Question 40

What are the disadvantages of using enzymes in industry?

Answer 40

Some people can develop allergies to the enzymes. Enzymes can be denatured by even a small increase in temperature, also susceptible to poisons and changes in pH, meaning they have to be tightly controlled. Contamination of the enzyme with other substances can affect the reaction.