Enzymes

Question 1

What are protein molecules made up of?

Answer 1

Long chains of amino acids

Question 2

What does the shape of a protein depend on?

Answer 2

Its function

Question 3

Complete the sentence:

The long chains of amino acids that make up proteins are…

Answer 3

…folded to produce specific shapes

Question 4

What can proteins be in the body?

Answer 4

• Structural components of tissues (such as muscle)
• Hormones
• Antibodies
• Catalysts

Question 5

What are chemical reactions in cells controlled by?

Answer 5

Proteins called enzymes

Question 6

What are enzymes?

Answer 6

Proteins which act as biological catalysts

They increase the rate of reaction without being used up themselves

Question 7

What is the ‘active site’?

Answer 7

The site/part of an enzyme where reactants bind

The area for other molecules to fit into

Question 8

What is a substrate?

Answer 8

The molecule or chemical on which an enzyme acts

Question 9

What can happen to the substrate held in the active site?

Answer 9

It can either be connected to another molecule or broken down

Question 10

What can enzymes do?

Answer 10

• Build large molecules from many smaller ones (e.g. building starch from glucose)
• Change one molecule into another (e.g. convert one type of sugar into another)
• Break down large molecules into many smaller ones (e.g. digestive enzymes)

Question 11

Why do enzyme reactions take place faster when it is warmer?

Answer 11

At higher tempertatures the molecules move around more quickly.

This means they collide with each other more often and with more energy

Question 12

What happens when an enzyme becomes denatured?

Answer 12

The active site to change shape

This means the enzyme doesn’t work properly any more

Question 13

What can cause an enzyme to denature?

Answer 13

If the pH is too acidic/alkaline

If the temperature is too great

Question 14

Do all enzymes require the same pH?

Answer 14

No!

Question 15

Do all enzymes work inside body cells?

Answer 15

No!

Digestive enzymes are produced in glands + the lining of the gut. They then pass out of these cells and come into contact with food

Question 16

What is digestion?

Answer 16

The breakdown of large, insoluble molecules itno smaller, soluble ones

Question 17

Describe the function of amylase

Answer 17

• A carbohydrase
• Catalyses the digestion of starch into sugars
• This is done in the mouth and small intestine
• It is produced by the salvary glands, pancrease, and small intestine

Question 18

Describe the function of protease

Answer 18

• Catalyses the breakdown of proteins into amino acids
• This occurs in the stomach and small intestine
• It is produced in the stomach, pancreas, and small intestine

Question 19

Describe the function of lipase

Answer 19

• Calalyses the breakdown of lipids (fats + oils) to fatty acids and glycerol
• This occurs in the small intestine
• It is produced by the small intestine and pancreas

Question 20

What is glycerol?

Answer 20

A building block of lipids

Question 21

How is digestion sped up in the stomach?

Answer 21

• Enzymes in the stomach work (such as protease) best in acidic conditions
• Glands in the stomach wall produce hydrochloric acid to create very acidic conditions

Question 22

How is digestion sped up in the small intestine?

Answer 22

• Amylase and lipase work in the small intestine
• They work best when the conditions are slightly alkaline
• The liver produces alkaline bile which is stored in the gall bladder.
• This is then squirted into the small intestine to neutralise the stomach acid and make conditions slightly alkaline

Question 23

How do biological detergents use enzymes and how does this make them useful?

Answer 23

• Contain proteases and lipases that digest food stains
• Work at lower temperatures then ordinary washing powders
• This saves energy and money spent on electricity
• Can be used to digest blood, grass, and gravy stains (yummy)

Question 24

How can protease be used in industry?

Answer 24

To pre-digest proteins in some baby foods

This makes it easier for babies to get the nutrients they need to grow when they are learning to eat solid food

Question 25

How is isomerase used in industry?

Answer 25

To convert glucose syrup into fructose syrup

Fructose is sweeter, so less is needed in foods

This means the foods are not as fattening

Question 26

How is carbohydrase used in industry?

Answer 26

To convert starch into sugar syrup for use in foods

Question 27

How are enzymes used in industry?

Answer 27

To bring about reactions at normal temperatures and pressures

Traditional chemical processes require expensive equipment and a lot of energy to produce high temperatures and pressures

Question 28

What are the advantages of using enzymes?

Answer 28

• Enzymes in biological washing powders are very effective at removing stains such as blood, grass, and gravy
• Biological washing powders can be used at lower temperatures, reducing energy used and costs
• Some are used in medicine to diagnose, control, or cure disease
• In industry, costs of equipment and energy can be reduced

Question 29

What are the disadvantages of using enzymes?

Answer 29

• People may have allergic reactions to washing powders on their skin. The enzymes are encolsed in capsules in the dry powder. Once the powder is dissolved, hands should not be placed in the water.
• Enzymes may enter waterways via the sewage system
• Industrial enzymes can be costly to produce
• Enzymes denature at the high temperatures needed to kill pathogens in washing
• Some fabrics, such as wool, will be digested by proteases