Enzymes

Question 1

Which enzyme works best in acidic conditions?

Answer 1

protease or pepsin

Question 2

What is the optimum temperature for enzymes in the human body?

Answer 2

37 degrees celsius

Question 3

What type of enzyme is amylase?

Answer 3

Carbohydrase

Question 4

How does hydrochloric acid in the stomach help digestion?

Answer 4

Provides optimum pH for protease enzymes

Question 5

Which enzyme breaks down starch?

Answer 5

amylase

Question 6

Which enzyme works best in alkaline conditions?

Answer 6

lipase

Question 7

Where do protease enzymes act?

Answer 7

stomach and small intestine

Question 8

Why are enzymes described as specific?

Answer 8

Each active site has a specific shape that fits only one type of substrate

Question 9

Where does absorption take place?

Answer 9

small intestine

Question 10

Where does carbohydrate digestion occur?

Answer 10

mouth and small intestine

Question 11

What happens when an enzyme is heated up too high?

Answer 11

the active site changes shape so the substrate is no longer able to bind to it - It becomes denatured

Question 12

Describe how to test for proteins

Answer 12

Add Biuret solution to the sample and it will turn from blue to lilac if protein is present

Question 13

Describe how to test for glucose

Answer 13

Add benedict’s reagent to the sample and heat/boil it. It will turn from blue to brick red if glucose is present.

Question 14

Describe how to test for starch

Answer 14

Add iodine solution to sample and it will turn from orange-brown to blue-black if starch is present

Question 15

Which acid is found in the stomach?

Answer 15

Hydrochloric Acid

Question 16

Why does increasing temperature increase the rate of enzyme activity?

Answer 16

Enzyme and substrate molecules have more kinetic energy so they move faster and collide more frequently. More enzyme-substrate complexes are formed as a result.

Question 17

What are the products of fat digestion?

Answer 17

Fatty acids and glycerol

Question 18

Which enzyme breaks down protein?

Answer 18

protease

Question 19

Describe 2 roles of bile

Answer 19

1. Emulsifies fat creating a larger surface area for lipase enzymes to act. 2. Bile is an alkali so neutralises the acid contents from the stomach providing the optimum pH for lipase

Question 20

Where does fat (lipid) digestion occur?

Answer 20

small intestine

Question 21

What provides alkaline conditions in the small intestine?

Answer 21

bile

Question 22

Where are lipase enzymes produced?

Answer 22

Pancreas and small intestine

Question 23

Which enzymes breaks down fats?

Answer 23

lipase

Question 24

where are carbohydrase enzymes, like amylase, produced?

Answer 24

salivary glands, pancreas, small intestine

Question 25

Where are protease enzymes produced?

Answer 25

Stomach, pancreas, small intestine

Question 26

Explain the lock and key theory

Answer 26

The substrate (lock) has a complementary shape to the enzyme's active site (key) so it will bind to it to form an enzyme-substrate complex (lock and key). The substrate is broken down into products which are then released. If the substrate's shape (lock) isn't complementary to the enzymes active site (incorrect key), then it doesn't bind together.

Question 27

Which organ produces bile?

Answer 27

liver

Question 28

Describe how the villi in the small intestine are adapted for their function

Answer 28

Many villi/microvilli which provide a large surface area for absorption. They are one cell thick so provide a short diffusion distance. They have a good blood supply which maintains a steep concentration gradient. They contain many mitochondria to provide energy for active transport

Question 29

Describe how to test for fats

Answer 29

Add ethanol to food sample and mix. Then add it to water and if a white emulsion forms fat is present.

Question 30

What are the products of starch digestion?

Answer 30

Sugars

Question 31

What are the products of protein digestion?

Answer 31

amino acids

Question 32

Which organ stores bile?

Answer 32

gallbladder

Question 33

Why does digestion occur?

Answer 33

To break large, insoluble molecules into small, soluble ones so they can be absorbed into the bloodstream