digestion

Question 1

Enzyme

Answer 1

• protein molecule
• biological catalyst
• speeds up chemical reactions without itself undergoing any chemical change

Question 2

Protease only acts in an

Answer 2

acidic medium

Question 3

amylase acts in an

Answer 3

alkali medium

Question 4

lipase acts in an

Answer 4

alkali medium

Question 5

Where are the enzymes secreted?

Answer 5

small intestine and pancreas

Question 6

explain the function of bile (4)

Answer 6

• Bile is produced in the liver and stored in the gallbladder
• alkali-neutralises stomach acid
• emulsifies fats into droplets- large SA:VR.

Question 7

ingestion

Answer 7

intake of food

Question 8

digestion

Answer 8

breakdown of large food molecules into small food molecules, Mechanically and chemically (enzyme) for absorption.

Question 9

What happens in the mouth?

Answer 9

mastication

Question 10

Absorption

Answer 10

Food particles diffusing into the villi/microvilli of the small intestine into the bloodstream.

Question 11

Assimilation

Answer 11

The build up of new molecules in the body from smaller food molecules eg: new cells, tissues

Answer 12

1, ingestion
2, Peristalsis
3, digestion
4,absorption
5, assimilation
6, egeStion

Question 13

EgeStion

Answer 13

A process during which Solid faeces is removed.

Question 14

Ball of food

Answer 14

Bolus

Question 15

Peristalsis

Answer 15

The wave-like movement of a bolus of food because of muscular contractions.

Question 16

SM^2ART

Answer 16

• large SA:VR to maximise the rate of diffusion
• surfaces need to be moist for easy absorption
• mitochondria- cellular respiration to release energy for active transport
• rich blood supply in the villi and microvilli: creates a high concentration gradient
• 1 cell Thick: shorter diffusion path

Question 17

coeliac disease

Answer 17

• The microvilli are damaged and this reduces the SA for absorption of food molecules
• Fewer amino acids and glucose molecules are absorbed
• less glucose means less respiration meaning less energy
• Fewer amino acids –> less proteins –> smaller growth

Question 18

Food tests-starch

Answer 18

-To the test sample, add a few drops of iodine

Original colour-brown. If it turns blue black starch is present.

Question 19

Food tests-protein

Answer 19

To the test sample add a few drops of biuret. Goes from blue to purple.

Question 20

Food tests-glucose

Answer 20

Heat the test sample to about 50/60/70 degrees. Add a few drops of Benedict’s solution. Blue –> green/red (depends on concentration)

Question 21

Food tests-lipids

Answer 21

emulsion using suDan 111. Swirl the contents. If there is a reD ring, it confirms lipiDs.