B2.5 - Proteins - Their Functions And Uses

Question 1

What can proteins act as? (4)

Answer 1

1. Hormones.
2. Antibodies.
3. Catalysts.
4. Structural components of tissues e.g. muscles.

Question 2

What is the name of molecules that fit with a specific enzyme?

Answer 2

Substrates.

Question 3

How many reactions can each enzyme catalyse?

Answer 3

One.

Question 4

What happens when an enzyme works at too high a temperature?

Answer 4

The bonds holding the enzyme together break, and it is now denatured.

Question 5

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

Answer 5

37 degrees.

Question 6

What pH do most enzymes work best at?

Answer 6

7.

Question 7

Which enzyme works best at pH 2 and why?

Answer 7

Pepsin, because it breaks down proteins in the stomach, which is highly acidic (because of the hydrochloride acid).

Question 8

Digestive enzymes break down ___,___ molecules into ___,___ molecules.

Answer 8

Large, insoluble.

Small, soluble.

Question 9

What does starch get broken down into and how?

Answer 9

Maltose and other sugars, by amylase.

Question 10

What do proteins get broken down into and how?

Answer 10

Amino acids, by protease.

Question 11

What do lipids (fats and oils) get broken down into and how?

Answer 11

Glycerol and fatty acids, by lipase.

Question 12

Where is amylase produced? (3)

Answer 12

1. Salivary glands.
2. Pancreas.
3. Small intestine.

Question 13

Where is protease produced? (3)

Answer 13

1. Stomach.
2. Pancreas.
3. Small intestine.

Question 14

Where is lipase produced? (2)

Answer 14

1. Pancreas.

2. Small intestine.

Question 15

Where is bile produced?

Answer 15

The liver.

Question 16

Bile is stored in the ___ ____ before being released into the ____ _____.

Answer 16

Gall bladder, small intestine.

Question 17

What does bile do in the small intestine? (2)

Answer 17

1. Because bile is alkaline, it can neutralise the hydrochloric acid from the stomach, which would have too high a pH for most enzymes to work in.
2. Bile emulsifies fats, and therefore digestion is faster because the fat droplets have a greater surface area.

Question 18

What pH conditions to enzymes in the small intestine work best in?

Answer 18

Alkaline.

Question 19

What are proteases and lipases used for in the home?

Answer 19

Biological detergents, as they are able to digest the stains.

Question 20

What is an advantage of biological detergents?

Answer 20

They are more effective at lower temperatures than other detergents.

Question 21

What is a use of protease in industry?

Answer 21

In baby foods to ‘pre-digest’ the proteins.

Question 22

What is a use of carbohydrase in industry?

Answer 22

To concert starch into sugar syrup.

Question 23

What is a use of isomerase in industry?

Answer 23

To convert glucose syrup into fructose syrup, which is a lot sweeter and hence is used in smaller quantities in slimming foods.

Question 24

What are the advantages of using enzymes in industry?

Answer 24

They are able to perform at normal temperatures and pressures, and therefore expensive equipment does not have to be bought.

Question 25

What are the disadvantages of using enzymes in industry?

Answer 25

They become denatured at high temperatures, and many are expensive to produce.

Question 26

What are protein molecules made from?

Answer 26

Large chains of amino acids.