ch3 Organisation and the digestive system

Question 1

Test for simple carbs(reducing sugars)

Answer 1

Benedict’s solution
heat in a water bath
blue to green to yellow to orange to brick red precipitate

Question 2

Test for fat

Answer 2

ethanol

colourless to white emulsion

Question 3

Test for protein

Answer 3

Biuret

blue to lilac/purple

Question 4

Test for starch

Answer 4

Iodine

yellow-brown to blue/black

Question 5

amylase

1. produced in the
2. breaks down
3. into

Answer 5

1. small intestine, salivary glands and pancreas
2. starch,
3. maltose and other sugars

Question 6

lipase

1. produced in the
2. breaks down
3. into

Answer 6

1. pancreas and small intestine
2. lipids
3. glycerol and 3 fatty acids

Question 7

protease

1. produced in the
2. breaks down
3. into

Answer 7

1. stomach, pancreas and small intestine
2. protein
3. amino acids

Question 8

Factors affecting enzymes

Answer 8

change in pH
when temperature reaches over 40°C (best condition is 37°C)

if this happens, the enzymes denature meaning the active site has changed shape

Question 9

enzymes

Answer 9

large protein molecule made up of a long chain of amino acids that are coiled and folded to produce a unique active site
acts as a catalyst

Question 10

lock and key theory

Answer 10

Enzymes have an active site that has a unique shape that bind to a specific corresponding substrate
Once in place, they bind together and products are then released from the surface of the enzyme
The breakdown of the substrate is catalysed

Question 11

Metabolic reactions

Answer 11

• conversion of glucose to starch, glycogen and cellulose
• the formation of lipid molecules from a molecule of glycerol and three molecules of fatty acids
• the use of glucose and nitrate ions to form amino acids which are used to synthesise proteins
• respiration
• breakdown of excess proteins to form urea for excretion

Question 12

bile

1. made in the…
2. stored in the…

Answer 12

liver

gall bladder

Question 13

uses of bile

Answer 13

neutralises hydrochloric acid from the stomach(alkaline)

emulsifies fat to form small droplets to increase their SA
- increase rate of fat breakdown by lipase