Carbohydrates Flashcards
3 Main types of Carbohydrates in our diet?
Starch 60%, Sucrose 30%, Lactose 10%
All naturally occurring sugars are:
D isomers
Starches are all polymers of
alpha-D glucose
Starches have two structural types:
Amylose and Amylopectin
Amylose contains which types of bonds?
Alpha 1-4 glycosidic bonds “Linear”
Amylopectin contains which types of bonds?
Alpha 1-6 glycosidic bonds “For branching”
Starches are mixtures of
15% Amylose and 85% Amylopectin
Reducing end
Unlinked anomeric position
non-reducing end
Unlinked 4 position
why is cellulose indigestible to humans?
we do not have a beta-1-4 glycosidic enzyme
In glucose which carbon is termed the anomeric carbon?
1st carbon because it is an aldehyde
In Fructose which carbon is termed the anomeric carbon?
2nd carbon because it is a ketone
define anomeric carbon
carbon of the carbonyl which becomes assymetric
what are the products of salivary alpha 1-4 amylase on amylose?
Maltose, maltotriose, oligosaccharides
what are the products of salivary alpha 1,4 amylase on amylopectin?
alpha dextrin, maltotriose, maltose
Which Carbohydrates are digested during the luminal phase of intestinal digestion?
Starches “Amylose and Amylopectin” and Glycogen
Which Carbohydrates are digested during the Membrane phase of intestinal digestion?
lactose, sucrose, maltose, maltotriose, and dextrins
Which glucose transporter is sodium dependent? SGLT-1 or GLUT-2
SGLT-1 “Active Transport”
Which transporter would fructose use to enter the enterocyte?
GLUT-5 “has a high affinity for fructose”
Which transporter would galactose use to enter the enterocyte?
SGLT-1
Which transporter would glucose use to enter the enterocyte?
SGLT-1 and GLUT-5 to a small extent due to GLUT-5’s higher affinity for Fructose transport
Which uses active transport and which uses facilitated diffusion? SGLT-1 and GLUT-5,GLUT-2
SGLT-1= active transport GLUT-5 and GLUT-2= facilitated diffusion
Which tissues would have a high concentration of GLUT-1?
Red blood cells and blood brain barrier because it is expressed in cell types with barrier functions.
Which tissues would have a high concentration of GLUT-2?
Liver, pancreatic beta cells, contraluminal membrane of intestinal epithelial cells.