Digestion n lip Bio Flashcards
Main dietary carbs their components and linkages
Starch:amylose-straight chain.alpha 1-4
Amylopectin:branched but less branches then glycogen,alpha 1-4 and alpha 1-6
Sucrose-alpha beta 1-2
Lactose-beta 1-4
In mouth which enzyme acts on carbs,what’s the major product that enters stomach
In the mouth, salivary alpha-amylase cleaves starch by breaking a-1,4 linkages between glucose residues within the chains
- Dextrins (linear and branched oligosaccharides) are the major products that enter the stomach.
How ph of acidic carbs is changed in intestine
It releases bicarbonate (HCO3À) secreted by the pancreas neutralizes the stomach acid, raising the pH into the optimal range for the action of the intestinal enzymes.
Which enzyme works in intestine to break carbs ,which bonds it breaks and what are it’s products
The pancreas secretes an alpha -amylase that acts in the lumen of the small intestine and, like salivary amylase, cleaves a-1,4 linkages between glucose residues.
The products of pancreatic a-amylase are the disaccharides maltose and isomaltase, trisaccharides, and small oligosaccharides containing a-1,4 and a-1,6 linkages.
In pancreatitis patients serum level of which enzymes disturb.. and their level î or !
Amylase and lipase levels î
Enzymes released by brusg borders of intestinal cells and what do they do
Isomaltase- cleaves a-1,6 linkages, releasing glucose residues from branched oligosaccharides.
Glucoamylase-breaks alpha 1-4 linkages of oligosachharides
Sucrase converts sucrose to glucose and fructose.
Lactase (a b-galactosidase) converts lactose to glucose and galactose.
Bloating, abdominal cramps, and watery diarrhea result due to
Lactase deficiency occurs in more than 80% of Native, African, and Asian Americans. Lactose is not digested at a normal rate and accumulates in the gut, where it is metabolized by bacteria. Bloating, abdominal cramps, and watery diarrhea result.
Carb that’s not digestible and why
enzymes produced by human cells cannot cleave the b-1,4 bonds of cellulose, this polysaccharide is indigestible.and is a part of deitary fiber
What happen to TAGs in intestine..which substances are released by gall bladder and pancreas…… bile salts are resorbed in
(Gall bladder release bile salts to emulsify lipids.pancreas release hco3-,pancreatic lipase, colipase)….
(TAGs are converted by pancreatic lipase with aid of colipase into 2-monoacyl glycerols and free fatty acids…. which convert into micelle(microdroplets of fats+cholestrol+bile salts+fat soluble vitamins).. which are then absorbed by microvilli)
……. (bile salts are resorbed in the terminal ileum
What’s the anti-obesity drug and what it does
The antiobesity drug, orlistat, inhibits pancreatic and gastric lipase, resulting in about 30% blockage of dietary fat from digestion and absorption, leading to reduction in body weight in some patients.
Synthesis of chylomicrons
Fatty acids absorbed in epithelial cells of intestine are activated into fatty acyl CoA by enzyme fatty acyl Co-A synthetase . Fatty acyl Co-A combines with 2-monoacylglycerol to from diacylglycerol which combines with another fatty acid to from triglyceride.TAGs are passed into lymph packaged in new chylomicrons which then enter in blood
Which substances convert the following zymogen forms of carbs into active forms
1) Pepsinogen
2) Trypsinogen
3) Chymotrypsinogen
4) Proelastase
5) Procarboxypeptidases
1) H+
2) enteropeptidase
3) Trypsin
4) trypsin
5) trypsin
Write the specificity of different peptidases
Pepsin but tends to cleave peptide bonds in which the carboxyl group is contributed by the acidic amino acids, aromatic amino acids, or leucine.
Trypsin cleaves peptide bonds in which the carboxyl group is contributed by arginine or lysine……… Chymotrypsin usually cleaves peptide bonds at the carboxyl group of aromatic amino acids or leucine……….. Elastase cleaves at the carboxyl end of amino acid residues with small, uncharged side chains such as alanine, glycine, or serine…….. Carboxypeptidase A cleaves aromatic amino acids from the C terminus…… Carboxypeptidase B cleaves the basic amino acids, lysine and arginine, from the C terminus.
Examples of endopeptidases and exopeptidases
Endopeptidases—1)trypsin 2)chymotrypsin 3)elastase
Exopeptidases—1)carboxypeptidase A
2)carboxypeptidaseB
Transport of amino acids into bloodstream
The major transport system involves cellular uptake by the cell of a sodium ion and an amino acid by the same carrier protein on the luminal surface.
b. The sodium ion is pumped out of the cell into the blood by the Na+ -K + ATPase, whereas the amino acid travels down its concentration gradient into the blood.
c. Thus, amino acid transport from the intestinal lumen to the blood is driven by hydrolysis of adenosine triphosphate (ATP) (secondary active transport).
Bicarbonate is released by ___in response to ____,failure to neutralise the acidic contents result in____
Bicarbonate is released from the pancreas in response to the hormone secretin, which is synthesized by the cells lining the duodenum. Failure to fully neutralize the acidic gastric contents results in peptic ulcers in the duodenum.
