diet and digestion Flashcards

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1
Q

key adaptations of the villi

A
  • large surface area (villi and microvilli)
    -> increases rate of diffusion
  • good blood supply
    -> maintain concentration gradient of blood
  • lacteal absorbs lipids
  • long
    -> lots of chance for diffusion to occur
  • thin/near capillary
    -> short diffusion distance
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2
Q

what is assimition

A

small food molecules are used to build larger molecules (e.g. amino acids are used to synthesise proteins)

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3
Q

what is absorbtion

A

small, soluble molecules move from the small intestine to the blood

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4
Q

what is ingestion

A

food enters the digestive system via the mouth

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5
Q

what is egestion

A

removal of undigested food (faeces) from the anus

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6
Q

what is digestion

A

breakdown of large insoluble molecules into small soluble ones

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7
Q

what is mechanical digestion

A

teeth break down food into small pieces and peristalsis helps to move food along

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8
Q

what is chemical digestion

A

enzymes break down food to small soluble molecules

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9
Q

what is the order of digestion

A

mouth -> oesophagus -> stomach -> duodenum -> ileum -> colon -> rectum -> anus

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10
Q

function of salivary glands

A

produces saliva
-> helps to moisten food
-> contains enzyme salivary amylase which starts the breakdown of food

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11
Q

function of the mouth

A

food is ingested
mechanical digestion occurs here - teeth cut and crush food into smaller pieces which increases the surface area for enzymes to work

food is mixed with salivary - contains digestive enzymes (salivary amylase) to break down starch and moisten food

form a bolus of food which is pushed to the back of the mouth using the tongue

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12
Q

function of the teeth

A

involved in mechanical digestion (physical breakdown of food)

incisor - for cutting and biting
canine - for holding and cutting
premolar and molar - for crushing and chewing

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13
Q

function of the oesophagus

A

food passes down oesophagus and into the stomach
food is moved through the digestive system via peristalsis
- circular and longitudinal muscles involved to produce wave-like contractions

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14
Q

function of the stomach

A

muscular bag that stores food for several hours

secrete HCl which makes stomach very acidic - the acid kills bacteria so you don’t get food poisoning and provides optimum pH for pepsin

produces the enzyme pepsin, which breaks down proteins to dipeptides

muscles in the wall of the stomach contract and churn the food

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15
Q

function of the liver

A

filters toxins from the blood

acts like a food processing factory and will break down some molecules and build/store others

produces bile which emulsifies lipids

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16
Q

function of the gall bladder

A

stores bile and releases bile into bile duct to enter the duodenum
in the duodenum bile has two roles:
- neutralising acids
- emulsifying lipids

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17
Q

function of the pancreas

A

produces trypsin, lipase, pancreatic amylase

these are released into duodenum for chemical digestion

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18
Q

function of the duodenum

A

food is continued to be broken down here, resulting in lots of small soluble molecules that can be absorbed in the ileum

bile (neutralises HCl from stomach) creates an alkaline environment, which is ideal for the enzymes maltese and peptidase

19
Q

function of the ileum

A

absorption of small soluble molecules into the blood stream and lacteal (absorbs fats)

villi has key adaptations to quickly and efficiently absorb soluble products of digestion

20
Q

function of the large intestine

A

any excess water is absorbed in the first part of the large intestine, the colon

leaving the non soluble/indigestible food (cellulose, dead and living cells from the gut) to move through

21
Q

function of the rectum

A

stores the faeces

22
Q

function of the anus

A

expels faeces from the body (egestion - removal of indigestible material)

23
Q

salivary amylase

A
  • produced in the salivary glands
  • used in the mouth
  • breaks down starch
  • end products are disaccharides (e.g. maltose)
  • optimum pH 7-8
24
Q

pancreatic amylase

A
  • produced in the pancreas
  • used in the duodenum
  • breaks down starch
  • end products are disaccharides (e.g. maltose)
  • optimum pH is 7-8
25
Q

maltase

A
  • produced in the duodenum
  • used in the duodenum
  • breaks down maltose
  • end products are glucose
  • optimum pH 7-8
26
Q

pepsin

A
  • produced in the stomach
  • used in the stomach
  • breaks down protein
  • end products are dipeptides
  • optimum pH 1-2
27
Q

trypsin

A
  • produced in the pancreas
  • used in the duodenum
  • breaks down protein
  • end products are dipeptides
  • optimum pH 1-2
28
Q

peptidase

A
  • produced in the duodenum
  • used in the duodenum
  • breaks down dipeptides
  • end products are amino acids
  • optimum pH 1-2
29
Q

lipase

A
  • produced in the pancreas
  • used in the duodenum
  • breaks down triglycerides
  • end products are glycerol and fatty acids
30
Q

practical: effect of temperature on enzyme activity

A
  • will use bacterial amylase to breakdown starch
  • can measure the activity of the enzyme by looking at the speed at which the starch disappears
  • will use iodine to work out when the reaction is finished - iodine will be blue/black

independent - temp
dependant - speed of colour change
controls - pH level, volume of starch, volume of iodine, volume of bacterial amylase

1) place single drops of iodine into depressions on a spotting tile
2) prepare a water bath for 20, 30, 40, 50, 60, 70 degrees celsius
3) place 2cm^3 of amylase into a test tube then put one in each water bath for 5 mins
4) add 2cm^3 starch into each amylase solution
5) place one drop of mixture into each drop of iodine - wait 10 seconds in between each drop
6) stop when the solution stays orange
7) each iodine drop used equals 10 seconds of reaction time
8) repeat for all temps

31
Q

what elements are found in carbohydrates

A

carbon, oxygen, hydrogen

32
Q

what elements are found in lipids

A

carbon, oxygen, hydrogen

33
Q

elements present in proteins

A

carbon, oxygen, hydrogen, nitrogen, sometimes sulphur

34
Q

monosaccharide example

A

glucose, fructose, galactose

35
Q

what is formed when two monosaccharides join together

A

a disaccharides

36
Q

disaccharides example

A

maltose, lactose, sucrose

37
Q

what is formed when lots of monosaccharides join together

A

polysaccharide

38
Q

polysaccharide examples

A

starch, glycogen, cellulose

39
Q

what a lipids

A

triglycerides

40
Q

what are triglycerides made of

A

1x glycerol
3x fatty acids

41
Q

what are triglycerides made of

A

1x glycerol
3x fatty acids

42
Q

what is the monomer of proteins

A

amino acids

43
Q

what are two amino acids joined together called

A

dipeptide

44
Q

what are many amino acids joined together called

A

polypeptide