Digestion 3 Flashcards

1
Q

what are the three types of carbohydrates

A

polysaccharides
disaccharides
monosaccharides

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2
Q

two are the two types of polysaccharides

A

starch and cellulose

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3
Q

what are the three types of disaccharides

A

sucrose, maltose, and lactose

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4
Q

what are the three types of monosaccharides

A

glucose, fructose, galactose

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5
Q

what type of carbohydrates can humans absorb?

A

monosaccharides
the other types have to be broken down further into things we can digest

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6
Q

what is starch broken down into

A

individual glucose molecules

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7
Q

how are carbohydrates broken down in the oral cavity

A

broken down by salivary amylase produced by salivary glands
starch molecules are made of glucose molecules; salivary amylast breaks the bonds between the glucose molecules

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8
Q

why can’t carbohydrates be broken down in the stomach

A

salivary amylase is inavtivated by the stomach’s chyme
carbohydrates must be broke down in the small intestine

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9
Q

how are carbohydrates broken down in the small intestine

A

broken down by pancreatic amylase produced in the pancreas
pancreatic amylase continues digestion of starch
we get maltose, glucose, and oligosaccharide strand
brush border enzymes complete starch breakdown

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10
Q

which three brush boarder enzymes complete starch breakdown

A

dextrinase, glucoamylase, and maltase

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11
Q

how do dextrinase and glucoamylase work to complete starch breakdown

A

break bonds between glucose subunits of oligosaccharides

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12
Q

how does maltase work to complete starch breakdown

A

breaks bonds between a maltose molecule (molecule with 2 glucose molecules)

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13
Q

what does lactase do

A

digests lactose molecule into glucose and galactose

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14
Q

what does sucrase do

A

digests sucrose molecule into glucose and fructose

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15
Q

explain how monosaccharides are absorbed

A

transported across the intestinal epithelial lining and into the blood by secondary active transport
sodium and potassium are pumped against their concentration gradient using a sodium/potassium ATPase pump
energy created allows monosaccharides to move through a monosaccharide carrier into the blood
they move across the basolateral membrane by facilitated diffusion then enter blood via intercellular clefts

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16
Q

where do monosaccharides go once they get into blood and what are they used for there

A

once in the venous blood, monosaccharides go to the liver
fructose and galactose converted to glucose
glucose can then be used for energy, converted and stored as glycogen, or converted into fat

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17
Q

how is protein broken down in the stomach

A

pepsinogen is activated to become pepsin
pepsin denatures proteins to facilitate chemical breakdown

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18
Q

what is the fiber adding bulk to the lumen content

A

cellulose, a carbohydrate component of plant cell wall that we can’t digest

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19
Q

what is the structure of a protein molecule

A

polymer made of amino acid subunits that are linked by peptide bonds

20
Q

how is protein digested in the stomach

A

starts to be digested by the activated form of pepsinogen, pepsin

21
Q

how is protein broken down in the small intestine

A

enzymes released from the pancreas continue protein digestion

22
Q

what are the 3 enzymes released by the pancreas to assist protein breakdown in the small intestine

A

trypsinogen, chymotrypsinogen, and procarboxypeptidase

23
Q

where is enteropeptidase released from and what does it do

A

released from brush border of epithelial cell
activates trypsinogen to trypsin

24
Q

what does trypsin do

A

activates more trypsinogen to trypsin
activates chymotrypsinogen to chymotrypsin
activates procarboxypeptidase to carboxypeptidase
also breaks bonds between specific amino acids to produce smaller strands of peptides

25
what do trypsin and chymotrypsin do
break bonds between specific amino acids to produce smaller strands of peptides
26
what does carboxypeptidase do
breaks bonds between amino acids on carboxyl end and the remaining protein
27
where is dipeptidase released from and what does it do
released from brush border of epithelial cells breaks final bond between two amino acids
28
what does aminopeptidase do
generates free amino acids which are used as building blocks for new proteins or converted into glucose
29
what is a triglyceride molecule made of
glycerol and three fatty acids
30
what are the 2 enzymes that break down lipids in the stomach
lingual lipase and gastric lipase
31
what produces gastric lipase
chief cells of the stomach
32
how is lipid digested in the stomach
lingual lipase and gastric lipase digest 30% of triglycerides to diglyceride and fatty acid
33
how are lipids digested in the small intestine
pancreatic lipase digests triglycerides (in micelles) into monoglycerides and two fatty acids requires triglycerides to be emulsified first
34
how does emulsification work for lipid digestion
bile salts from the liver and gallbladder emulsify lipid droplets to form micelles
35
explain the organization of a micelle
molecules with polar head and nonpolar tail nonpolar tails line up around fat droplet with heads toward the aqueous fluid **allows greater access of pancreatic lipase to triglyceride**
36
how are lipids absorbed
monoglycerides and free fatty acids are transported to epithelial lining by micelles they enter the cells, bile salts stay in the lumen in the cell, monoglycerides and free fatty acids re-form into triglycerides and are wrapped in protein to form chylomicrons chylomicrons are released by exocytosis and enter lacteals to get to the blood
37
what are nucleic acids and what are the two types
polymers of nucleotides DNA and RNA
38
what makes up a DNA and RNA molecule
sugar, phosphate group, and nitrogenous base
39
how are nucleic acids broken down in the small intestine
deoxyribonuclease and ribonuclease released by the pancreas break phosphodiester bonds between nucleotides of DNA and RNA phosphatase and nucleosidase from brush border phosphatase breaks bonds holding phosphate nucleosidase breaks bonds between sugar and nitrogenous base
40
what is hepcidin and what does it do
hormone released from the liver **inhibits absorption of iron**
41
which vitamins are water soluble and how are they absorbed
B and C absorbed through diffusion and active transport
42
which vitamins are fat soluble and where are they absorped
A, D, E, and K absorbed in small intestine with lipids
43
how is water absorbed
by osmosis
44
where and how are electrolytes absorbed
absorbed mostly in the small intestine usually unregulated and dependent on diet
45
how is vitamin B12 absorbed
by receptor-mediated endocytosis requires intrinsic factor which is formed by parietal cells in the stomach