Biology: Digestive System etc

Question 1

mouth

Answer 1

teeth mechanically break down food
larger surface area for enzyme action

Question 2

oesophagus

Answer 2

connects mouth and stomach

Question 3

peristalsis

Answer 3

how food bolus moves through gut

Question 4

stomach (4 things)

Answer 4

churns food to break down further and mix
releases proteases and hydrochloric acid- helps to sterilise food
has epithelial cells in stomach lining to stop acid (why bile is needed in s.i.

Question 5

what makes a effective diffusion surface (in body)

Answer 5

large surface area
good blood supply
short diffusion distance

Question 6

small intestine, adaption to help function

Answer 6

nutrients absorbed into bloodstream BY ACTIVE TRANSPORT (only soluble food molecules)
villi greatly increases surface area along with folded shape

Question 7

large intestine/colon (2 things)

Answer 7

absorbs water
forms faeces

Question 8

gut flora (4 purposes)

Answer 8

bacteria in our gut:
break down substances we can’t digest
supply essential nutrients
synthesise (put together) vitamin K
compete with harmful bacteria (restricts their growth)

Question 9

rectum

Answer 9

stores faeces- mainly indigestible food

Question 10

anus

Answer 10

muscle controlled opening out of the body

Question 11

salivary glands

Answer 11

produce amylase
lubricates food bolus for easy swallowing

Question 12

bile- purpose

Answer 12

to emulsify fats (break them down into smaller globules so they have more surface area for enzyme action)
neutralises stomach acid

Question 13

bile- where produced and stored

Answer 13

produced in liver
stored in gall bladder

Question 14

pancreas

Answer 14

produce amylase, protease, lipase

Question 15

enzyme (and what are they made from)

Answer 15

biological catalyst
made from proteins/amino acids

Question 16

3 fun facts abt digestive enzymes

Answer 16

work outside body cells
produced by glands
secreted into the digestive tract

Question 17

pH of oral cavity

Answer 17

6.8-7.5

Question 18

pH of stomach cavity

Answer 18

1.5-2.0

Question 19

duodenum what

Answer 19

first part of small intestine

Question 20

pH of duodenum

Answer 20

5.6-8

Question 21

pH of small intestine

Answer 21

7.2-7.5

Question 22

pH of colon

Answer 22

7.9-8.5

Question 23

difference between simple and complex carbohydrates

Answer 23

complex: longer chains eg starch
take longer to digest
shorter: opposite eg sugar

Question 24

carbohydrates -> ?? used for what?

Answer 24

glucose- fuel for respiration- to release energy

Question 25

proteins -> ?? used for what?

Answer 25

amino acids- building new proteins for growth and repair, also enzymes and antibodies

Question 26

lipids-> ?? used for what?

Answer 26

fatty acids and glycerol- used to rebuild lipids for use as an energy store insulation protect vital organs and build cell membranes and hormones

Question 27

carbohydrase- where produced, action

Answer 27

saliva -> mouth pancreas -> small intestine small intestine

Question 28

protease- where produced, action

Answer 28

stomach pancreas -> small intestine small intestine

Question 29

lipase- where produced, action

Answer 29

pancreas -> small intestine

Question 30

eg of carbohydrase

Answer 30

amylase

Question 31

eg of protease

Answer 31

pepsin: stomach trypsin: pancreas -> small intestine

Question 32

starch food test

Answer 32

iodine orange/brown blue/black

Question 33

sugar food test

Answer 33

benedict’s light blue green to brick red 85 celsius water bath for 5 mins (this is so solution can get to the same temperature of the water bath) qualitative test so no good for diabetics! hahaha 😝

Question 34

lipid food test

Answer 34

ethanol clear and colourless cloudy emulsion

Question 35

protein food test

Answer 35

biuret blue lilac/purple avoid getting on skin / wear gloves / wear safety goggles because Biuret solution / reagent is corrosive

Question 36

specificity of enzymes

Answer 36

a substrate (reactant) can only be binded if it has a complementary shape (enzymes are folded to produce a unique shape)

Question 37

how is enzyme held together

Answer 37

by forces between amino acids (enzymes are large protein molecules / chains of amino acids)

Question 38

lock and key theory

Answer 38

- substrate temporarily binds to enzymes active site- forms an ENZYME-SUBSTRATE COMPLEX - bonds broken - enzyme converts substrate into product(s)- forms an ENZYME-PRODUCT COMPLEX products released from enzymes active site- enzyme remains unchanged

Question 39

induced fit theory

Answer 39

shape of enzymes active site and substrate are not complementary when substrate enters active site, a conformational change occurs

Question 40

denatured

Answer 40

when the shape of an enzymes active site is distorted and its substrate can no longer fit (reaction is not catalysed) largely irreversible

Question 41

enzymes and temperature

Answer 41

low temp: little kinetic energy few successful random collisions more kinetic energy as temp increases, more collisions optimum temp: most successful collisions (37 celsius in human body) active site deforms above that decreasing successful collisions as bonds are broken get to a point where there are no successful collisions

Question 42

enzymes and pH

Answer 42

optimum pH: most successful collisions this value depends on the enzyme moving away: become denatured fewer successful collisions extreme pH: no activity- completely denatured

Question 43

metabolism

Answer 43

sum of all the reactions in a cell/organism

Question 44

examples of synthesis in humans

Answer 44

starch, glycogen, cellulose from glucose proteins from amino acids in ribosomes lipids from fatty acids and glycerol

Question 45

examples of synthesis in plants

Answer 45

glucose from carbon dixode and water amino acids from glucose and nitrate ions

Question 46

anabolic reaction

Answer 46

synthesis reaction

Question 47

catabolic reaction, example

Answer 47

breaking down reaction (big to small) eg digestion cellular respiration (glucose -> water and co2) deamination (excess amino acids -> urea)

Question 48

reactions that happen in plants and humans

Answer 48

respiration and protein synthesis

Question 49

what happens to excess proteins/amino acids

Answer 49

converted to urea- excreted in urine

Question 50

what is the point of digestion

Answer 50

make molecules smaller and SOLUBLE to be absorbed into blood

Question 51

EXAM Q: investigating breakdown of starch by amylase: why is it better to measure concentration of starch rather than just if it is present

Answer 51

more accurate, quantitive, less subjective

Question 52

EXAM Q: what will happen to enzymes at 80 degrees??

Answer 52

THEY WILL DENATURE AND SO WONT COLLIDE etcetc!! AT ALL.

Question 53

in biology, how to do describe graph questions

Answer 53

PUT DATA FROM GRAPH IN

Question 54

why/how does small intestine absorb nutrients

Answer 54

into blood by active transport

Question 55

what affects metabolic rate

Answer 55

genetics, age, gender, body mass

Question 56

how to determine concentration of solution inside an egg using solutions of water

Answer 56

put egg inside at least 4 solutions of different water potentials, record changes in mass and plot each eggs results on a graph. then see where graph crosses x axis (no change in mass), would tell each eggs concentration)

Question 57

exam q: how do pancreas and gall bladder work together to digest fats (6!)

Answer 57

 lipids are broken down by lipase  lipase is produced in the pancreas  bile is produced in the liver and stored in the gall bladder  bile and lipase are both secreted / released into the small intestine  bile neutralises the acidic food / hydrochloric acid from the stomach  lipase works optimally in alkaline conditions / in a high pH  bile emulsifies the fat into tiny droplets  this increases the surface area for lipase to work on (speeding up the rate of digestion)