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YEAR 12- biology a-level > 3.3.3 digestion and absorption > Flashcards

3.3.3 digestion and absorption Flashcards

1
Q

what is the process of carbohydrate digestion

A

starch is hydrolysed by salivary amylase

starch is hydrolysed into maltose by amylase

any undigested starch is hydrolysed to maltose by pancreatic amylase

maltose is hydrolysed by membrane bound maltase in ileum

maltose is hydrolysed into 2 glucose molecules

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2
Q

where is amylase produced

A

salivary gland
small intestines
pancreas

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3
Q

where does amylase act

A

mouth
small intestine

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4
Q

what substrates are hydrolised by amylase

A

amylose/ starch

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5
Q

what are the products produced by amylase

A

sugars

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6
Q

what are the products produced by amylase used for

A

energy release by respiration

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7
Q

where is protease produced

A

stomach
pancreas
small intestine

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8
Q

where does protease act

A

stomach
small intestine

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9
Q

what substrates are hydrolised by protease

A

proteins

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10
Q

what are the products produced by protease

A

amino acids

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11
Q

what is chemical digestion

A

chemicals / enzymes produced by organs used to digest food

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12
Q

what is mechanical digestion

A

use of physical structures to break down food

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13
Q

what is the function of the mouth

A

tongue and teeth used to chew food

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14
Q

what is the function of the salivary glands

A

produces the salivary amylase enzyme

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15
Q

what is the function of the oesophagus

A

pushes food down to the stomach using muscles which contract

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16
Q

what is the function of the stomach

A

produces protease and HCl destroys pathogens

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17
Q

what is the function of the large intestines

A

absorbs water from food

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18
Q

what is the function of the small intestines

A

produce amylase, lipase and protease
co transport of molecules
absorbs food molecules

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19
Q

what is the function of the rectum

A

stores faeces

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20
Q

what is the function of the anus

A

egestion, waste is removed

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21
Q

what is the function of the liver

A

makes bile to neutralise acid before reaching the small intestines
(bile- emulsifies fats)

22
Q

what is the function of the pancreas

A

makes lots of chemicals

23
Q

what is the function of the gall bladder

A

stores bile produced in stomach

24
Q

examples of chemical digestive organs

A

salivary glands
stomach
small intestine
pancreas
liver

25
Q

examples of mechanical digestive organs

A

mouth
oesophagus
stomach
large intestine
small intestine
rectum
anus

26
Q

where is lipase produced

A

small intestines
pancreas

27
Q

where does lipase act

A

small intestine

28
Q

what are the substrates that get hydrolised by lipase

A

lipids

29
Q

what are the products produced by lipase

A

fatty acids
gluderol

30
Q

what are the products of lipase used for

A

making call membranes

31
Q

what is the process of digestion

A

digestion is the process of breaking large molecules of food into smaller molecules to be absorbed into cells for chemical reactions

32
Q

after starch (carbohydrate) is digested into glucose, what happens to the glucose?

A

glucose is absorbed from the ileum into bloodstream via co transport
1. sodium leaves the cell via active transport using atp, through sodium potassium pump which creates a concentration gradient
2. glucose binds to sodium ions and goes through a channel protein
3. glucose exits cell via facilitated diffusion through glut2 channel into bloodstream

33
Q

how is protease able to work in the stomach

A

it’s optimum ph is 2 so it does not get denatured by HCl

34
Q

what is the process of protein digestion in the stomach

A
  1. exopeptidase- hydrolised terminal peptide bonds in a polypeptide
  2. endopeptidase- hydrolises internal bonds and produce smaller polypeptides with more ends for faster hydrolysis
  3. exopetidase + endopeptidase can’t hydrolyse dipeptides as they aren’t complimentary
  4. membrane bound dipeptidase hydrolised peptide bonds in dipeptides into 2 amino acids
35
Q

what si the function of exopeptidase

A

hydrolised the terminal bonds on the outside of polypeptides

36
Q

what is the function of endopeptidase

A

hydrolised internal bonds on the inside of a polypeptide

37
Q

what is the function of dipeptidase

A

hydrolyse peptide bonds in dipeptides into 2 amino acids

38
Q

why does exopeptidases alone digest polypeptides slowly

A

there are less ends which leads to slower rate of hydrolysis

39
Q

how does salivary amylase digest starch

A

hydrolised it using water to break glycosidic bonds and for maltose

40
Q

what is maltose hydrolised into

A

2 glucose molecules

41
Q

what is the process of protein absorption

A

1.sodium ions exit ileum via active transport using ATP through sodium potassium pump which creates a concentration gradient in bloodstream
2. amino acid bind to sodium and enter ileum cell via facilitated diffusion through a channel protein
3. amino acids exit ilium cell via facilitated diffusion by carrier proteins back into the bloodstream

42
Q

what are the adaptations of the ileum epithelial cells

A

wall of the ileum cell is folded into many microvili supplied with capillaries= large SA, thin diffusion distance, maintains blood concentration of glucose

43
Q

what types of lipids does lipase break down

A

triglycerides

44
Q

what does lipase hydrolise a triglyceride into

A

triglyceride> diglyceride> monoglyceride + 2 FA

45
Q

why does lipase struggle to digest lipids

A

lipase is an enzyme/ protein which is soluble in water, lipids are insoluble

46
Q

why is the reaction of lipase slow

A

triglycerides are hydrophobic and it’s difficult for dissolved lipase to approach them

47
Q

what is the function of bile

A

emulsify fats to help lipase digest them

48
Q

what is the function of bile salts

A

emulsify fats to make lipids water soluble
causes lipids to form small droplets

49
Q

what is the process of lipid digestion

A

the hydrophobic part of the bile salt binds to the fat globule
hydrophilic part of the bile salt attracts water which the lipase is dissolved in
lipase is then able to bind to the triglyceride to digest and produce 1 monoglyceride and 2 fatty acids

50
Q

what is the process of lipid absorption

A

monoglyceride and 2 fatty acids combine with bile salts and form micelles
micelles carry contents to epithelial cells membrane in small intestines
monoglycerides and fatty acids can simply diffuse into cell and reform a truglyceride using lipase
triglycerides combine with lipoproteins and cholesterol to form chylomicrons
chylomicrons are packages into vescicles which move to cell membrane and are released into the lymph

51
Q

why does ph of solution decrease during lipid digestion

A

more fatty acids are released from triglycerides which decrease ph

52
Q

how do bile salts increase rate of digestion

A

emulsify lipids and make them smaller to make them soluble in water so lipase is able to hydrolyse it

YEAR 12- biology a-level (6 decks)

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