Lesson 7: Digestion

Question 1

What is the function of the mouth?

Answer 1

• Mechanical digestion with the teeth.

- Salivary glands release amylase: carbohydrase enzyme.

Question 2

What is the wave-like contraction that moves the globule of food down the oesophagus called?

Answer 2

The wave-like contraction is called peristalsis.

Question 3

What is the function of the stomach?

Answer 3

• Plummets food with muscular walls
• Releases pepsin (protease enzyme.)
• Produces hydrochloric acid to kill bacteria and provide environment for pepsin.

Question 4

What is the function of the pancreas?

Answer 4

• Produces lipase, protease, carbohydrase enzymes.

- Secretes into small intestine as pancreatic fluid.

Question 5

What is the function of bile?

Answer 5

• Neutralizes stomach acid for enzymes in small intesine.

- Emulsifies fats

Question 6

What is “emulsification?”

Answer 6

Emulsification is the breakdown of large fat droplets into small droplets.

Question 7

What does emulsifying fats do?

Answer 7

• Breaking down large droplets into smaller droplets.
• Increasing the surface area.
• Increasing the rate of fat breakdown by lipase.

Question 8

What does neutralizing stomach acid do?

Answer 8

• Creates optimum pH for enzymes in small intestine.

- Increase the rate of fat breakdown by lipase

Question 9

What is the function of the small intestine?

Answer 9

• Absorbs food into the blood by diffusion.

Question 10

What enzymes does the small intestine release?

Answer 10

• Protease, amylase (carbohydrase) ,lipase.

Question 11

What is the function of the large intestine?

Answer 11

• Absorbs excess water –> (into bloodstream) producing faeces.

Question 12

What is the function of the rectum?

Answer 12

• Faeces are stored here until they pass out of the anus.

Question 13

What is the function of the gall bladder?

Answer 13

• Bile is stored here before secreted into small intestine.

Question 14

Give 3 main types of tissue

Answer 14

• Glandular tissue
• Epithelial tissue
• Muscular tissue

Question 15

What is glandular tissue?

Answer 15

• A group of cells that secrete digestive juices (enzymes) to break down food.

Question 16

What is epithelial tissue?

Answer 16

• A group of cells that form the lining of organs in body.

Question 17

What is muscular tissue?

Answer 17

• A group of cells that contract and relax to allow motion

Question 18

What does muscular tissue do in the stomach to food?

Answer 18

• Contracts to pulverize (break down) the food.

Question 19

What does glandular tissue in the stomach do?

Answer 19

• Releases digestive juices such as: enzymes and hydrochloric acid.

Question 20

What does epithelial tissue in the stomach do?

Answer 20

• Epithelial tissue covers outside of the stomach (protect from hydrochloric acid)

Question 21

What does muscular tissue in the small intestine do?

Answer 21

• Contracts to move food along.

Question 22

Describe the role of liver in digestion of fats.

Answer 22

• Produces bile
• Emulsifies fats –> large surface area for enzyme to work on.
• Neutralises stomach acid –> create optimum pH for lipase to work at.

Question 23

Q: Some students investigated the effect of pH on digestion of an egg white. The pH that broke down the most egg white is the optimum.
This may not be the exact pH.
Explain what the students could do to find more accurate value for pH.

Answer 23

• Repeat
• Smaller intervals used between pH’s.

Question 24

Q.)

Describe, in as much detail as you can, what happens to the protein after food A is
swallowed. (4)

Answer 24

• Digested
• By protease
• In stomach, small intesine, pancreas (releases protease enzymes)
• Amino acids are soluble (can be absorbed into blood stream.)

Question 25

Why can’t we just absorb food without breaking it down?

Answer 25

• Molecules not soluble.
• Molecules too big.

Question 26

Q.)

What is the function of muscle cells on lining of stomach? (2 marks)

Answer 26

• Churn food by contraction

Question 27

What is the function of the digestive system?

Answer 27

• To break down and absorb food.

Question 28

What is a tissue?

Answer 28

• A tissue is a group of cells with similar structure and function.

Question 29

What is an organ?

Answer 29

• An organ is a group of tissues that work together to carry out a particular function.

Question 30

How is the stomach churning food increase digestion?

Answer 30

• Gives food larger surface area for enzymes to work on.

Question 31

What are the products of digestion used for?

Answer 31

• The products of digestion are used to build new carbohydrates, lipids and proteins, that is useful for the body.
• Some glucose is used fo respiration.

Question 32

What is digestion?

Answer 32

Digestion is the break down of large, insoluble molecules into small, soluble molecules so it can be absorbed into the blood.

Question 33

What are the 2 types of digestion?

Answer 33

• Mechanical digestion.
• Chemical Digestion

Question 34

What is mechanical digestion?

Answer 34

• Mechanical digestion is when food is physically pulverised ad churned by stomach and teeth.

Question 35

What is chemical digestion?

Answer 35

Chemical digestion is when food is broken down by enzymes.

Question 36

What 2 things does bile do that increases the fat breakdown by lipase?

Answer 36

1.) Increase surface area of fat molecules.
2.) Creates alkaline conditions (optimum pH)