Food science + the digestive system

Question 1

how to test for starch

Answer 1

add iodine solution directly, orange –> black

Question 2

how to test for protein

Answer 2

add biurets, blue –> purple

Question 3

how to test for sugars

Answer 3

add benedicts blue –> red
(+heat) (warm water bath)

Question 4

fats / lipids

Answer 4

add ethanol clear–>cloudy

Question 5

catalysts

Answer 5

chemicals that can be used to speed up (or slow down) a reaction , but is not used up in the reaction itself

Question 6

enzyme

Answer 6

a biological cataylyst

Question 7

3 things enzymes do

Answer 7

• build larger molecules (synthetize)
  -break down larger molecules
  -change one molecule into another

Question 8

give example of an enzyme making larger molecules

Answer 8

creating amino acids from protein

Question 9

what are enzymes made of

Answer 9

large protein molecules made from folded coiled chains of amino acids

Question 10

the active site

Answer 10

the area that attaches to the substrate (reactant) has a very specific shape that fits its substrate exactly

Question 11

Mouth

Answer 11

Teeth
-break down food, increases sa, easier for enzymes to break down
-eases swallowing

Salivatory glands
-contains amylase , digestion of carbohydrates

Question 12

Oesophagus

Answer 12

pushes food down to stomach

Question 13

Stomach

Answer 13

• contracts muscular wall
• contains protease to digest proteins
• contains HCL provides correct PH for enzymes

Question 14

Pancreas

Answer 14

releases pancreatic juices (mix of enzymes) to small intestine

Question 15

Gall bladder

Answer 15

Liver makes bile, stored in gallbladder and released by //

Question 16

Purpose of bile

Answer 16

-neutalises acid from stomach
- emulsifying lipids (increases sa)

Question 17

Small intestine

Answer 17

• fully digests partially digested food by releasing digestive enzymes
• nutrients are absorbed from the intestine into the blood stream

Question 18

Villi adaptations diffusion

Answer 18

• large sa
• single layer of cells = thin exchange surface
• good blood supply = maintains conc gradient

Question 19

Large intestine

Answer 19

absorbs excess water

Question 20

rectum and anus

Answer 20

stpres feces + releases

Question 21

carbohydrates become.. with enzyme..

Answer 21

carbohydrase amylase

Question 22

proteins become.. with enzyme

Answer 22

amino acids protease

Question 23

fats / lipids become.. with enzyme

Answer 23

fatty acids / glycerol lipase

Question 24

which organs contain amylase

Answer 24

mouth (saliva)
pancreas
small intestine

Question 25

which organ contains protease

Answer 25

stomach pancreas small intestine

Question 26

optimal temperature

Answer 26

the temperature at which the rates of enzymes controlled reactions are fastest

Question 27

explain the relationship between enzyme ROR and temperature

Answer 27

as temperature increases kinetic energy of the enzyme and the substrate increases successful collisions increase between substrate and active site , increasing ROR

Question 28

explain temperature increases above optimum

Answer 28

-increased kinetic energy begins to damage structure of the enzyme active site is no longer specific to substrate ROR decreases , denatured enzyme

Question 29

issues with accuracy with controlled enzyme reactions

Answer 29

we cannot conclude optimum temp, may keep increasing time intervals too large lower precision end point subjective , color change

Question 30

relationship between enzyme ROR and ph

Answer 30

if pH becomes more alaki / acidic than optimum rate , ROR decreases, enzyme denatured

Question 31

amylase pH

Answer 31

neutral

Question 32

protease pH

Answer 32

acidic

Question 33

lipase pH

Answer 33

alakline

Question 34

explain ROR and enzyme conc relationship

Answer 34

- as conc of enzyme increases, ROR increases -fixed conc of substrate : plateaus -substrate conc increases : ROR increases

Question 35

ROR and substrate conc

Answer 35

increases, limiting factor substrate conc plateaus, limiting factor enzyme conc

Question 36

describe a method to investigate the effect of pH on the rate of starch breakdown by amylase

Answer 36

1) add iodine to spotting tile, 2 drops per well 2) measure 5cm3 of starch solution and amylase solution , mix together in a test tube , CV 3) add controlling pH solution, the conc is CV 4)using a pipette drop the amylase starch mixture into each well at 15 second intervals , stopping when the solutions stop color changing from orange to blue/black 5) repeat the experiment with same pH controlling solution and calculate mean 6) repeat with different concs of pH solution , calculate means

Question 37

a patient has pancreatic cancer, a symptom is weight loss, explain

Answer 37

- no / less digestive enzymes produced - less food absorbed - less fatty acids + glycerol to store fats