DIGESTION, ABSORPTION AND RENAL SYSTEM Flashcards
WHAT TYPE OF GLYCOSIDIC BONDS ALLOWS FOR BRANCHING OF GLUCOSE RESIDUES (E.G. IN THE POLYSACCHARIDE STARCH)
ALPHA 1,6 GLYCOSIDIC BONDS
MECHANICAL AND CHEMICAL DIGESTION OF CARBOHYDRATES BEGINS WHERE?
in the mouth
WHAT ENZYME BREAKS DOWN THE ALPHA 1,4 GLYCOSIDIC BONDS?
ALPHA-AMYLASE
WHAT IS THE NAME OF THE LINEAR AND WHAT OF THE BRANCHED COMPONENT OF STARCH?
AMYLOSE - LINEAR
AMYLOPECTIN - BRANCHED
WHERE DOES THE MOST AND WHERE DOES THE LEAST OF CARBOHYDRATE DIGESTION OCCUR?
MOST IN THE SMALL INTESTINE, LEAST IN THE STOMACH
WHAT ARE AMYLOSE AND AMYLOPECTIN BROKEN DOWN INTO BY THE SALIVARY AMYLASE?
SMALLER CHAINS OF GLUCOSE CALLED DEXTRINS AND THE DISACCHARIDE MALTOSE
WHERE IS ALPHA AMYLASE DENTAURED?
IN THE STOMACH
THE MOST IMPORTANT ENZYME IN THE CARBOHYDRATE DIGESTION?
PANCREATIC AMYLASE
HOW ARE DISACCHARIDES BROKEN DOWN INTO MONOSACCHARIDES IN THE SMALL INTESTINE?
BY DISACCHARIDASES IN THE LUMINAL MEMBRANE OF THE BRUSH BORDER
WHAT DOES THE PANCREATIC ALPHA AMYLASE DO AFTER IT IS RELEASED INTO THE SMALL INTESTINE AS A COMPONENT OF PANCREATIC JUICE?
RESUMES THE BREAKDOWN OF DEXTRINS INTO SHORTER CARB CHAINS, MALTOSE AND OTHER DISACCHARIDES
ONCE CARBOHYDRATES ARE BROKEN DOWN INTO MONOSACCHARIDES (GLUCOSE, FRUCTOSE OR GALACTOSE), HOW AND WHERE ARE THEY TRANSPORTED?
INTO THE INTESTINAL CELLS, GLUCOSE AND GALACTOSE VIA ACTIVE TRANSPORT, FRUCTOSE VIA FACILITATED DIFFUSION
CHAIN OF UP TO HOW MANY AMINO ACIDS CAN BE SAFELY ABSORBED BY HUMANS?
UP TO 3 (TRIPEPTIDES)
WHERE DOES CHEMICAL (ENZYMATIC) DIGESTION (BREAKING DOWN OF PEPTIDE BONDS) OF THE PROTEINS START?
IN THE STOMACH
WHAT KIND OF PROTEIN DIGESTION OCCURS IN THE MOUTH?
MECHANICAL; LARGE PROTEIN PIECES SEPARATED THROUGH CHEWING
HOW ARE PROTEINS DENATURED AND THEIR 3D STRUCTURE UNFOLDED?
BY THE HYDROCHLORIC ACID
WHAT TYPES OF PROTEIN DIGESTION OCCUR IN THE STOMACH?
CHEMICAL AND MECHANICAL
WHICH CELLS SECRETE HCl?
PARIETAL
WHICH CELLS SECRETE PROENZYME (ZYMOGEN) PEPSINOGEN?
CHIEF (AKA ZYMOGENIC CELLS)
WHAT IS PEPSINOGEN?
INACTIVE FORM OF ENZYME PEPSIN RELEASED BY THE CHIEF CELLS IN THE STOMACH
WHAT STIMULATES CONVERSION OF PEPSINOGEN TO PEPSIN?
HCl LOWERING THE pH TO 3.5 (OPTIMAL pH FOR PEPSIN!!!)
WHAT PERCENTAGE OF INGESTED PROTEINS ARE DIGESTED BY PEPSIN AND WHAT DOES PEPSIN DO EXACTLY?
20%, BREAKS PEPTIDE BONDS
ORDER THE MAIN NUTRIENTS BASED ON THE TIME REQUIRED FOR THEIR DIGESTION, FROM LONGEST TO SHORTEST?
FAT, PROTEIN, CARBOHYDRATES
WHAT DOES DENATURATION DO TO PROTEINS?
MAKES THEM LOSE THEIR FUNCTION?
WHY IS INSULIN INJECTED RATHER THAN INGESTED?
BECAUSE IT IS A PROTEIN AND ITS FUNCTION WOULD BE DESTROYED BY DENATURATION AND ENZYMATIC FUNCTION IN THE STOMACH
WHERE DOES THE MAJORITY OF PROTEIN DIGESTION OCCUR?
IN THE SMALL INSTESTINE
WHAT ARE THE TWO PHASES OF PROTEIN DIGESTION IN THE SMALL INTESTINE?
LUMINAL PHASE - IN THE LUMEN OF THE INTESTINE WHERE DIGESTIVE JUICES ARE SECRETED
BRUSH BORDER PHASE - BY ENTEROCYTES AND MICROVILLI
WHAT ARE THE TWO MAJOR PANCREATIC PROTEASES (ENZYMES FOR PROTEIN DIGESTION)?
TRYPSIN AND CHYMOTRYPSIN
IN WHICH FORM DO THE PANCREATIC PROTEASES LEAVE THE PANCREAS?
PACKAGED INTO SECRETORY VESICLES AS INACTIVE PROENZYMES CALLED TRYPSINOGEN AND CHYMOTRYPSINOGEN
WHY ARE PANCREATIC PROTEASES RELEASED IN VESICLES, IN PRECURSOR FORM AND INCLUDING TRYPSIN INHIBITOR?
BECAUSE THEY ARE POTENTIALLY DANGEROUS ENZYMES IF ACTIVATED AT A WRONG PLACE
HOW ARE THE PANCREATIC PROTEASES ACTIVATED?
TRYPSINOGEN IS ACTIVATED (CONVERTED TO TRYPSIN) BY THE ENZYME ENTEROKINASE. TRYPSIN THEN ACTIVATES CHYMOTRIPSINOGEN AND ANY REMAINING MOLECULES OF TRYPSINOGEN.
CLASSIFICATION OF PROTEASES AND THE DIFFERENCE?
ENDOPEPTIDASES: CLEAVE PROTEINS IN THE MIDDLE OF THEIR CHAINS (TRYPSIN AND CHYMOTRYPSIN)
EXOPEPTIDASES: CLEAVE SINGLE AMINO ACIDS OFF THE FREE CARBOXYL ENDS OF PROTEINS
WHERE IS ENTEROKINASE RELEASED FROM?
DUODENAL MUCOSA
TRIPEPTIDES, DIPEPTIDES AND SINGLE AMINO ACIDS ENTER THE ENTEROCYTES BY ACTIVE OR PASSIVE TRANSPORT?
ACTIVE; REQUIRES ATP
WHAT HAPPENS TO THE PROTEINS WHICH AREN’T FULLY DIGESTED IN THE INTESTINE?
THEY PASS INTO THE COLON AND ARE EXCRETED IN FECES
HOW MUCH GRAMS OF FAT DOES FECES CONTAIN PER DAY?
LESS THAN 5g
WHICH MAIN NUTRIENT IS NOT WATER SOLUBLE?
LIPIDS
WHAT HAPPENS TO LIPIDS IN A WATERY ENVIRONMENT (LIKE THE GI TRACT)
THEY CLUSTER TOGETHER IN DROPLETS
WHERE DOES THE MOST OF ENZYMATIC DIGESTION OF LIPIDS OCCUR?
SMALL INTESTINE
WHERE IS THE LINGUAL LIPASE PRODUCED AND WHAT DOES IT DO?
BY THE CELLS ON THE TOUNGE, BEGINS SOME OF THE ENZYMATIC TRIGLYCERIDE DIGESTION
WHARE ARE THE NAMES OF LIPASES ACTIVE IN THE STOMACH?
GASTRIC AND LINGUAL LIPASE
HOW ARE BILE SALTS ABLE TO EMULSIFY WATER AND FAT, AND WHERE ARE THEY RELEASED
THEY ARE RELEASED IN THE DUODENUM. THEY HAVE HYDROPHOBIC AND HYDROPHILIC SIDES SO THEY ATTRACT BOTH FAT AND WATER.
WHY ARE LIPIDS EMULSIFIED?
TO BREAK DOWN FAT GLOBULES INTO SMALLER DROPLETS AND MAKE THEM MORE EASILY ACCESSIBLE BY DIGESTIVE ENZYMES BY INCREASING THE SURFACE AREA ON WHICH THEY CAN ACT
WHAT ARE MICELLES?
SMALL DROPLETS OF FAT SURROUNDED BY BILE