Digestion & Absorption - Macronutrients Flashcards
Where do CHO begin to be digested?
In the mouth
Where do proteins begin to be digested?
In the stomach
Where do the majority of macronutrients get digested primarily?
Small Intestine
Fats gets absorbed through _________
Lymph - central lacteals
What increases the surface area in the SI?
Extensive foldings
The folds of mucosa/submucosa are called _____________.
plicae circulares
The microscopic folds that further increase the surface area are called ______
Villi
When the apical membrane of villi, fold they are termed:
Microvilli
Celiac disease is associate with what in the villi?
Damaged villi
Which part of the intestinal foldings contain the brush border enzymes?
Microvilli
T/F Brush border enzymes get secreted into the intestinal lumen
False, they remain attached to the cell membrane
The brush border enzyme (BBE) required for activation of trypsin is _______________
Enterokinase
Which BBE split disaccharides?
- sucrase
- maltase
- lactase
CHO are divided into ___________ and ____________
Polysaccharides and Disaccharides
Polysaccharides are divided into ________, _____________ and _____________
- starch
- cellulose
- Glycogens
The starch polysaccharide is divided into amylose and amylopectin; which one is branched?
Amylopectin
Disaccharide Sucrose = __________ + glucose
fructose
Glucose + glucose = _____________ Disaccharide
maltose
Disaccharide lactose is __________ + glucose
galactose
Describe the glucose units bonding in starch
Alpha 1-4 linkages
Is amylose unbranched or branched?
Unbranched
Describe the glucose units linkage in cellulos
Beta 1-4
cellulose is branched or unbranched?
Unbranched
Which species do NOT have cellulase, thus they cannot break down cellulose?
Most monogastrics
Which polysaccharide is present in the exoskeleton of a lobster shell with a Beta 1-4 linkage?
Chitin
The correct term for the branched “animal starch” is ________________
Glycogen
What starts starch digestion in the mouth?
Ptyalin
_____________ is the how starch is digested in the small intestine
Pancreatic amylase
When starch is broken down, it is broken down into maltose and __________ (group of glucose polymers)
Dextrins
Which disaccharide is used to make glucose?
Maltose through amylase
Which cells absorb the monosaccharides?
Enterocyte
Which transporters are present in the LUMINAL membrane of the enterocyte?
SGLT-1 (sodium-glucose linked transporter 1)
GLUT 5
Which transporters are present BASOLATERAL membrane of the enterocyte?
GLUT 2 and 5
Which enterocyte transporters are associated with Glucose and galactose?
SGLT 1 and GLUT 2
The enterocyte transporter GLUT 5 is associated with what disaccharide ?
Fructose
Which basolateral transporter is the only observed in the brush border membrane when there are high glucose concentrations?
GLUT 2
Which disaccharide is transported via facilitated diffusion into enterocytes?
Fructose
The first enzymatic action for proteins happens in the _____________
stomach
___________________ (enzyme) result in tri/di peptides and single AA
Pancreatic proteases
Gastric pepsinogen is activated by _________ to pepsin
HCl
What does pepsin “attack” ?
Collagen
List the pancreatic enzymes
- trypsin
- chymotrypsin
- carboxypolypeptidase
- elastase - elastin fibers
In the SI, what are the enzymes called that digest proteins?
Peptidases
How are free single AA in enterocytes absorbed?
Co transported with Na
Di and tri peptides is by co-transport with which molecule?
H+ ions via PepT1
T/F the basolateral membrane have AA transports that are dependent on Na gradients
False
What is an exception where intact protein is absorbed?
Antibodies and a foreign food protein (ex:Botox)
Any substance of bio relevance composed of CHO insoluble in water is?
Lipids
Give an example of a phospholipids
Lecithin
___________ hydrolyzes fat
Lipase
Fat digestion mainly occurs in the SI of adults by ______________
Pancreas lipase
What produces lipase in neonates?
Salivary glands
How many Fatty acids are produced in hydrolysis?
2 Free Fatty acids
What is the stimulus for bile secretion?
Lipids in the duodenum
What is the process through which fat droplets are broken up into micelles?
Emulsication
Why are lipids emulsified?
TO present a larger surface area in the duodenum
What protein aids in the fat digestion by anchoring the droplets along with pancreatic lipase?
Colipase
Free cholesterol is done by the pancreatic enzyme _____________________
Cholesterol ester hydrolase
PLA2 hydrolyzes ___________ to yield FFA and lysophosppholipids
Phospholipids
What emulsifies fats?
Bile
Which chain of fatty acids from the TGs?
Long-chain fatty acids
TGs, phospholipids and cholesterol combined with the apoprotein form the _____________ inside the enterocytes
Chylomicrons
Chylomicrons are secreted into ________________
central lacteals
What removes the Tg content in blood vessels?
Lipoprotein lipase
Cholesterol and TGs combine with apoproteins to be secreted into the blood as ____________________ during fasting
Very-low-density- lipoproteins (VLDLs)
What can contribute to the development of artherosclerosis?
Low-density lipoproteins (LDLs)
Which lipoproteins are believed to be a protection against atherosclerosis?
High-density lipoproteins
