Biology Y10 Digestive System

Question 1

purpose of the digestive system

Answer 1

breaks down food into a soluble form for absorption into the bloodstream

Question 2

function of mouth

Answer 2

teeth mechanically break down food, large surface area for enzyme action

Question 3

function of oesophagus

Answer 3

connects mouth and stomach, peristalsis pushes food bolus along

Question 4

function of stomach

Answer 4

churns food to break down further and mix it, releases proteases and hydrochloric acid

Question 5

function of small intestines

Answer 5

soluble food molecules absorbed into blood, villi increase surface area

Question 6

function of large intestines

Answer 6

absorb water, form faeces

Question 7

function of gut flora

Answer 7

breaks down substances, supplies essential nutrients, synthesises vitamin K, competes with harmful bacteria

Question 8

function of rectum

Answer 8

store faeces

Question 9

function of anus

Answer 9

control opening of the body

Question 10

function of salivary glands

Answer 10

produce amylase, lubricate food bolus

Question 11

function of liver

Answer 11

produces bile to emusify fats, neutralises stomach acid

Question 12

function of gall bladder

Answer 12

stores bile for release

Question 13

function of pancreas

Answer 13

produces enzymes

Question 14

where is amylase produced

Answer 14

salivary glands, pancreas, small intestines

Question 15

where is protease produced

Answer 15

stomach, pancreas, small intestines

Question 16

where is lipase produced

Answer 16

pancreas

Question 17

where does amylase act

Answer 17

mouth, small intestine

Question 18

where does protease act

Answer 18

stomach, small intestine

Question 19

where does lipase act

Answer 19

small intestine

Question 20

what does amylase digest into what

Answer 20

starch -> glucose

Question 21

what does protease digest into what

Answer 21

proteins -> amino acids

Question 22

what does lipase digest into what

Answer 22

lipids -> 3 fatty acids and glycerol

Question 23

what pH is the stomach

Answer 23

1.5-2

Question 24

what pH does amylase work best at

Answer 24

~7

Question 25

what pH does protease work best at

Answer 25

~1.6

Question 26

what pH does lipase work best at

Answer 26

~8

Question 27

how does the stomach protect itself from the hydrochloric acid

Answer 27

has a thick mucus lining

Question 28

how to test for starch

Answer 28

iodine test

Question 29

how to test for sugar

Answer 29

benedict's test

Question 30

how to test for lipids

Answer 30

emulsion test (ethanol)

Question 31

how to test for protein

Answer 31

biuret test

Question 32

what colour is iodine test before and after a positive result

Answer 32

orange-brown -> blue-black

Question 33

what colour is benedict's test before and after a positive result

Answer 33

light blue -> green to brick-red

Question 34

what colour is emulsion test before and after a positive result

Answer 34

colourless -> cloudy emulsion

Question 35

what colour is biuret test before and after a positive result

Answer 35

blue -> lilac

Question 36

what are enzymes

Answer 36

large protein molecules folded to produce a unique shape (also biological catalyst)

Question 37

what is an enzyme made of

Answer 37

amino acids

Question 38

with what kind of substrate can an enzyme combine

Answer 38

complementary

Question 39

what is the lock and key theory

Answer 39

the enzyme has a specific shape that perfectly matches the sustrate

Question 40

what is a denatured enzyme

Answer 40

an enzyme whose shape has been distorted

Question 41

how can denaturing happen

Answer 41

temperature and pH

Question 42

what happens to an enzyme at low temperature

Answer 42

little kinetic energy = few collisions

Question 43

what happens to an enzyme at optimum temperature

Answer 43

the most successful collisions

Question 44

what happens to an enzyme at above optimum temperature

Answer 44

the active site deforms and hte enzyme begins to denature

Question 45

what happens to an enzyme at optimum pH

Answer 45

most successful collisions

Question 46

what happens to an enzyme at non-optimum pH

Answer 46

denatured = few successful collisions

Question 47

what happens to an enzyme at extreme pH

Answer 47

denatured = no activity

Question 48

what is metabolism

Answer 48

sum of all the reactions in a cell or organism

Question 49

what types of reactions do enzymes speed up

Answer 49

synthesis (small thing -> big things), changing one molecule to another and breaking down larger molecules into smaller ones

Question 50

what is glucose used for

Answer 50

fuel for respiration, to release energy

Question 51

what are amino acids used for

Answer 51

building new proteins for growth and repair, enzymes and antibodies

Question 52

what are glycerol and fatty acids used for

Answer 52

rebuilding lipids for energy store, insulation, protecting organs and new cell membranes and hormones

Question 53

what is optimum temperature for enzymes in humans

Answer 53

~37°C

Question 54

how to do iodine test

Answer 54

add a drop of sample and a drop of iodine and record changes in appearance

Question 55

how to do biuret test

Answer 55

add a drop of sample and a drop of biuret solution and record changes in appearance

Question 56

how to do benedict's test

Answer 56

get test tubes, put samples in each, put benedict's solution in each, heat up to 85°C for five minutes and record changes in appearance

Question 57

how to do emulsion test

Answer 57

add sample to test tube, add ethanol to the test tube and mix, have water in another test tube, pour ethanol mix into water, record changes in appearance