Digestion and absorption

Question 1

What are organs made of?

Answer 1

Organs are made of tissue

Question 2

What are proteins made up of?

Answer 2

Proteins are made up of long chains of amino acids.

Question 3

What are catalysts?

Answer 3

Catalysts are natural catalysts that increase the rate of reactions by lowering the activation energy.

Question 4

What factors can alter enzyme activity?

Answer 4

pH and Temperature alter enzyme activity

Question 5

Where is the enzyme amylase produced and what does it do?

Answer 5

Amylase is produced in the salivary glands and the pancreas. Amylase catalyses the breakdown of starch into maltose in the mouth and small intestine.

Question 6

Where is the enzyme protease produced and what does it do?

Answer 6

Protease enzymes are produced by the stomach and the pancreas. Proteases catalyse the breakdown of proteins into amino acids in the stomach and small intestine.

Question 7

Where is the enzyme lipase produced and what does it do?

Answer 7

Lipase enzymes catalyse the breakdown of lipids into fatty acids and glycerol in the small intestine. They are made in the stomach and small intestine.

Question 8

Where is bile produced?

Answer 8

Bile is stored in the liver

Question 9

Where is bile stored?

Answer 9

Bile is stored in the gall bladder

Question 10

What does bile do?

Answer 10

Bile neutralises the acid that is added to food in the stomach. This provides the conditions for the enzymes in the small intestine to work the best.

Question 11

What are the 4 stages of digestion?

Answer 11

1) Ingestion - Food is taken in
2) Digestion - Enzymes break large insoluble molecules into smaller soluble ones
3) Absorption - The products of digestion are absorbed through the lining of the intestine
4) Egestion - Removal of faeces

Question 12

What is protein hydrolysed to?

Answer 12

Protein is hydrolysed to amino acids

Question 13

What is starch hydrolysed to?

Answer 13

Starch is hydrolysed to simple sugars

Question 14

What are fats hydrolysed to?

Answer 14

Fats hydrolysed to a mixture of fatty acids and glycerol

Question 15

How are carbohydrates digested?

Answer 15

Sodium ions and glucose molecules are transported into the epithelial cells lining of the small intestine by facilitated diffusion. They enter through co-transport proteins. The sodium ions are then transported from the epithelial cells and into the blood. (insert diagram)

Question 16

What do mitochondria do?

Answer 16

Mitochondria are the energy factories of the cells. The energy currency for the work that animals must do is the energy-rich molecule adenosine triphosphate (ATP). The ATP is produced in the mitochondria using energy stored in food.

Question 17

What are the stages of protein breakdown?

Answer 17

Protein –> Polypeptides –> Dipeptides –> Amino acids

Question 18

Where is HCl produced?

Answer 18

HCl is produced in the stomach by parietal cells.

Question 19

What do chief cells produce?

Answer 19

Chief cells produce pepsinogen

Question 20

How are HCl and Pepsinogen linked?

Answer 20

Pepsinogen is activated as pepsin in the stomach by Hc;

Question 21

Why is pepsinogen needed?

Answer 21

Pepsin breaks down proteins and outside the stomach protective lining is not present so would break down tissue. The pepsinogen is not harmful so is used until its in the stomach which has a protective lining so pepsin is not harmful.

Question 22

Diagrams needed on the sodium-potassium pump.

Answer 22

NOW

Question 23

What is emulsification?

Answer 23

Emulsification (in digestion) The breakdown of fat globules in the duodenum into tiny droplets, which provides a larger surface area on which the enzyme pancreatic lipase can act to digest the fats into fatty acids and glycerol. Emulsification is assisted by the action of the bile salts (see bile)

Question 24

What is a bolus?

Answer 24

A saliva ball full of food which allows it to travel more easily

Question 25

Lipid diagram needed

Answer 25

ASAP p150

Question 26

What are the stages of lipid breakdown?

Answer 26

Lipid –> emulsified lipids –> fatty acids and glycerol