Digestion, Respiration & Circulation.

Question 1

What does the Mouth do?

Answer 1

It uses saliva, which contains salivary amylase, to break down starch into maltose.

Question 2

What does the stomach do?

Answer 2

It uses gastric juice, which contains pepsin, to break down proteins into polypeptides.

Question 3

What are enzymes?

Answer 3

They are biological or organic catalysts which can be found in all living organisms that speed up the rate of chemical reactions without themselves being changed and are mainly made of proteins.

Question 4

What can an enzyme do?

Answer 4

A small quantity of enzyme can bring about a large amount of chemical reaction and they are specific in action. A rate of enzyme reaction is fastest at optimum temperature.

Question 5

What is digestion?

Answer 5

Digestion is the mechanical and chemical breaking down of food into smaller components that can be absorbed into the bloodstream.

Question 6

What is peristalsis?

Answer 6

Wavy-like rhythmic contractions and relaxations of the longitudinal and circular muscles of the alimentary tract that helps push food down the gut and is a key feature in churning.

Question 7

What is Double Circulation?

Answer 7

It is the phenomenon whereby blood passes through the heart twice and once to the lungs and the other to the other parts of the body.

Question 8

What is a tissue fluid?

Answer 8

It is formed by blood plasma that leaks out and fills up the space between the capillaries.

Question 9

What is Aerobic Respiration?

Answer 9

It is the oxidation of glucose in the presence of oxygen with the release of a large amount of energy.

Question 10

What is Anaerobic Respiration?

Answer 10

It is the oxidation of glucose in the absence of oxygen with the release of a small amount of energy,

Question 11

How does Lactic Acid form?

Answer 11

It occurs in muscles where there is not enough O2 reaching the cells to convert all the glucose into CO2 and H20. Glucose is partially broken down, without CO2, to lactic acid, with only some energy being released.

Question 12

Which enzyme breaks starch into Maltose?

Answer 12

Amylase

Question 13

Which enzyme breaks proteins into polypeptides?

Answer 13

Trypsin

Question 14

Which enzyme breaks fats into fatty acids and glycerol?

Answer 14

Lipase

Question 15

Where are the 2 areas in which proteins is broken down in polypeptides?

Answer 15

1. Stomach (Pepsin)

2. Small Intestine, Duodenum (Trypsin)

Question 16

What does Mastication do?

Answer 16

It increases surface area to volume ratio.

Question 17

What do the Salivary glands do?

Answer 17

They secrete saliva which contains water, mucus and enzyme.

Question 18

What does the Tongue do?

Answer 18

It mixes food with saliva and rolls food into a bolus which is easier to swallow.

Question 19

What does the Oesophagus do?

Answer 19

It secrets Mucus that aids in the passage of food into the stomach.

Question 20

What does the Stomach do?

Answer 20

It contains acidic ph 2 and has muscular walls made up of circular and longitudinal muscles which are under involuntary control which helps in churning and mixes it with gastric juice.

Question 21

What is chyme?

Answer 21

It contains partially digested food and is passed in small amounts into the duodenum. The pyloric spinchter controls the amount of chyme that is passed from the stomach to the duodenum.

Question 22

What do gastric glands do?

Answer 22

It secretes gastric juice which contains hydrochloric acid which kills bacteria and provides an acidic environment for stomach enzymes which are pepsin and renin.

Question 23

What does the liver do?

Answer 23

It produces bile that is temporarily stored in the gall bladder and then secreted into the common bile duct that emulsifies fats. The liver neutralises the acidic chyme from the stomach and provides alkaline pH for the small intestine.

Question 24

What is emulsification?

Answer 24

It is the process whereby fats is broken down into smaller globules of and increases the surface area for the digestion of fats.

Question 25

What does the pancreas do?

Answer 25

It secretes insulin and pancreatic juice. The insulin breaks down glucose into glycogen and the pancreatic juice contains water that is used for hydrolysis and enzymes such as amylase, trypsin and lipase.

Question 26

What does the small intestine do?

Answer 26

It secrets intestinal juice and nutrients are absorbed into the bloodstream by the villus. A villi contains blood capillaries for the absorption of glucose, amino acids, minerals and other nutrients. The villus contain lacteal for absorption of fatty acids & glycerol and their subsequent recombinations to form fats and lipids

Question 27

What are the substances absorbed in the small intestine?

Answer 27

Simple sugars, Amino Acids and Mineral Salts/

Question 28

What are the substances absorbed in the large intestine?

Answer 28

Water and Mineral Salts

Question 29

What does the rectum do?

Answer 29

It stores undigested food such as dietary fibre as faeces until it is expelled through the anus.