Digestion Flashcards
what are the two types of starch we usually intake?
amylopectin and amylose
what is the linkage that amylose uses?
alpha1-4 bonds
what two linkages does amylopectin use?
alpha 1-4 and alpha 1-6
in addition to starch, what other common form of sugars do we intake?
disaccharides
salivary amylase breaks what bond?
alpha 1-4
pancreatic amylase breaks what bond?
alpha 1-4
what is the transporter for glucose across luminal surface in SI? what is the type of diffusion here? what molecule drives this process?
SGLT1
secondary active diffusion
driven by Na
what is the transporter for galactose across luminal surface in SI? what is the type of diffusion here? what molecule drives this process?
SGLT1
secondary active diffusion
driven by Na
what is the transporter for frcutose across luminal surface in SI? what is the type of diffusion here? what molecule drives this process?
GLUT5
passive diffusion
not linked
what is the basolateral membrane transporter that is used for all the monosaccharides?
GLUT2
name the three monosaccharides we can absorb
glucose
galactose
fructose
name the four BBE for carbohydrate metabolism
lactase
sucrase
maltase
dextrinase
what carbs does lactase break up
glu and gal
what carbs does sucrase break up
fructose and glucose
what carbs does maltase break up
glu and glu
what is the action of dextrinase
breaks alpha 1-6 bonds of glu-glu
what enzymes is in charge of activating trypsin into trypsinogen?
enterokinase
what is pepsin activated by?
HCl
where does pepsinogen break AA chains?
internally…endopeptidase
name the five pancreatic peptidases
trypsin chymotrypsin elastase carboxypeptidase A craboxypeptidase B
which two of the pancreatic peptidases are exopeptidases
carboxypeptidase A and B
name the two peptidases from the BBE in the SI
aminooligopeptidase
dipeptidase
how do we absorb protein? single amino acids, di and tri peptide or polypeptides?
single, di and tri…no poly
how are di and tripeptides brought in the luminal surface?
with a cotransporter of Hydrogen
how are free amino acids brought in the luminal surface?
with a Na cotrasnporter
what are the four steps of lipid absorption?
emulsification
lipid hydrolysis
micellization
lipid absorption
what is in charge of emulsifying fats?
bile
what type of fat does bile mainly emulsify?
triglycerides
name the three pancreatic lipases
lipase-colipase
phospholipase A2
cholesterol esterase
what type of molecule does cholesterol esterase work on? what does it break it into?
cholesterol ester
breaks into cholesterol and fatty acid
what type of molecule does regular lipases work on? what does it break it into?
triglycerides
breaks into monoglyceride and fatty acids
what type of molecule does phospholipase A2 work on? what does it break it into?
phospholipids
breaks into lysolecithin and a fatty acid
how many places can pancreatic lipase cleave a triglyceride? what does this lead to?
two…breaks it into two fatty acids and amonoglyceride
how many places can gastric lipase cleave a triglyceride? what does this lead to?
one..breaks it into a diglyceride and a fatty acid
what does pancreatic lipase need to be effective? why does gastric lipase not need this?
colipase…gastric does not need it because bile has not surrounded the lipids in the stomach
how does colipase help pancreatic lipase to digest lipids?
it binds the bile and the lipase and allows the lipase to get into the fat and start working
after pancreatic lipase works and you are left with fatty acids and monoglycerides…are these molecules hydrophobic or hydrophilic? what does this cause to happen?
hydrophobic…so they are put into micelles
what four things contribute to the formation of a micelle?
bile salts
cholesterol
fat soluble vitamins (DAKE)
lipid digestion components
what does the luminal surface of a cell actually absorb in lipid absorption?
micelles
once a micelle is absorbed what does the cell make out of it? why does it do this?
it makes it into a chylomicron to make sure the micelle does not leak back out the apical side of the cell and into the lumen
what can happen to the chylomicron in the eneterocyte? where does it travel after this?
it can be exocytosed…and go into the lacteal and into the subclavian
