Enzymes & Digestion

Question 1

What is the job of digestive enzymes?

Answer 1

To break down molecules that are too big to diffuse through walls in the digestive system.

Question 2

Name 3 molecules that have to be broken down by an enzymatic reaction and 4 molecules that are the product of an enzymatic reaction.

Answer 2

Big molecules: starch, proteins, fats.
Products: sugars, amino acids, glycerol, fatty acids.

Question 3

Which type of enzyme breaks down carbohydrates? Name an example of an enzyme that catalyses it and where the enzymes are found. What do carbohydrates become when broken down?

Answer 3

Type: carbohydrase
Broken down: starch
Example of carbohydrase: amylase
Where: salivary glands, pancreas, small intestine

Question 4

Which type of enzyme breaks down proteins? Where are the enzymes are found? What do proteins become when broken down?

Answer 4

Type: protease
Broken down: amino acids
Where: stomach, pancreas, small intestine

Question 5

What are protease called in the stomach?

Answer 5

Pepsin

Question 6

Which enzyme catalyses lipids? What do lipids become when broken down? Where is the enzyme found?

Answer 6

Type: lipases
Broken down: glycerol and fatty acids
Where: pancreas, small intestine

Question 7

Where are enzymes produced?

Answer 7

By specialised cells in glands and in the stomach lining

Question 8

What happens in the salivary glands?

Answer 8

Amylase enzymes are produced in the saliva

Question 9

What is the gullet?

Answer 9

The oesophagus

Question 10

What 3 things happen in the stomach?

Answer 10

1. It pummels the food with it’s muscular walls.
2. It produces the protease enzyme called pepsin.
3. Produces hydrochloric acid

Question 11

Why does the stomach produces hydrochloric acid?

Answer 11

1. To kill bacteria
2. Give the right pH level for pepsin to work (pH 2)

Question 12

What happens in the pancreas?

Answer 12

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

Question 13

What 2 things happen in the small intestine?

Answer 13

1. Produces protease, amylase and lipase to complete digestion.
2. This is where digested food is absorbed into the blood stream.

Question 14

What happens in the large intestine?

Answer 14

Excess water is absorbed from the food.

Question 15

What happens in the rectum?

Answer 15

Faeces is stored here.

Question 16

What happens in the liver and the gall bladder?

Answer 16

Liver: Where bile is produced.
Gall bladder: Where bile is stored before released into the small intestine.

Question 17

What are the two main functions of bile?

Answer 17

1. Neutralises hydrochloric acid because the pH level is too acidic for the enzymes in the small intestine.
2. Breaks fat into tiny droplets so that lipase has a bigger surface area to work with.
   This makes digestion faster.