Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
41 Cards in this Set
- Front
- Back
|
How much energy do we get from a carb?
|
4 Cal/gram (4 Kcal/g)
|
|
|
Major dietary sources of carbs: monosaccharides
|
- glucose
- fructose |
|
|
Major dietary sources of carbs: disaccharides
|
-maltose
-lactose -sucrose |
|
|
Major dietary sources of carbs: polysaccharides
|
-amylose
-amylopectin |
|
|
Where is alpha-amylase present? What can it break down? What are the end products?
|
- saliva & pancreas
-hydrolyzes starch alpha 1-->4 linkages, but not alpha 1-->6 linkages -end products: maltose, maltotriose, limit dextrins |
|
|
Lactose intolerance
|
-failure to digest lactose
-can be diagnosed by failure to observe glucose increase after lactose intake -bacteria act on it (make H2 gas & lactic acids/fatty acids) --> attracts water to make cramps & watery diarrhea |
|
|
Absorption of monosaccharides in small intestine: simple diffusion
|
monosaccharides can do this, but it is rare
|
|
|
Absorption of monosaccharides in small intestine: facilitated diffusion
|
-main way for sugars to get in
-Fructose & mannose & glucose |
|
|
Absorption of monosaccharides in small intestine: Active transport
|
-glucose (or galactose) brought into cell by active transport --> leave by diffusion
-based on sodium concentration which stays low inside cell |
|
|
Where do we find SGLT (sodium linked transporters)?
|
-intestinal mucosa
-kidney brush border |
|
|
Where do absorbed sugars from the intestine go?
|
-sugars enter capillaries --> portal circulation --> directly to liver
|
|
|
What are the glucose transporters?
|
GLUT1, GLUT2, GLUT3, GLUT4, GLUT5 & SLGLUT 1
|
|
|
Where does GLUT 4 act?
|
-acts in skeletal & cardiac muscle, fat cells, white blood cells
-stimulated by insulin to congregate @ membrane |
|
|
Where does GLUT2 work?
|
-liver, pancreas B cells
-not responsive to insulin |
|
|
Where does SlGLUT 1 work?
|
-intestinal epithelium, mucosal surface, kidneys
|
|
|
How does the liver regulate blood glucose level?
|
-keeps it relatively constant, except after meals, oscillating around 4.5 to 5mM
|
|
|
Absorption of monosaccharides in small intestine: facilitated diffusion
|
-main way for sugars to get in
-Fructose & mannose & glucose |
|
|
What are limit dextrins?
|
small residual linear & branched chains that cannot be broken down by alpha-amylase
|
|
|
Major dietary sources of carbs: disaccharides
|
-maltose
-lactose -sucrose |
|
|
Effect of diabetes on blood glucoses
|
- start higher blood glucose --> go higher --> come down slower
|
|
|
Major dietary sources of carbs: polysaccharides
|
-amylose
-amylopectin |
|
|
Absorption of monosaccharides in small intestine: Active transport
|
-glucose (or galactose) brought into cell by active transport --> leave by diffusion
-based on sodium concentration which stays low inside cell |
|
|
Which enzymes are found in the intestinal mucosa (brush border)?
|
-Maltase
-Isomaltase -Sucrase -Lactase |
|
|
What are limit dextrins?
|
small residual linear & branched chains that cannot be broken down by alpha-amylase
|
|
|
Where do we find SGLT (sodium linked transporters)?
|
-intestinal mucosa
-kidney brush border |
|
|
Where is alpha-amylase present? What can it break down? What are the end products?
|
- saliva & pancreas
-hydrolyzes starch alpha 1-->4 linkages, but not alpha 1-->6 linkages -end products: maltose, maltotriose, limit dextrins |
|
|
Where do absorbed sugars from the intestine go?
|
-sugars enter capillaries --> portal circulation --> directly to liver
|
|
|
Lactose intolerance
|
-failure to digest lactose
-can be diagnosed by failure to observe glucose increase after lactose intake -bacteria act on it (make H2 gas & lactic acids/fatty acids) --> attracts water to make cramps & watery diarrhea |
|
|
What are the glucose transporters?
|
GLUT1, GLUT2, GLUT3, GLUT4, GLUT5 & SLGLUT 1
|
|
|
What is dietary fiber made from? What is the purpose?
|
-undigested polysaccharides
-affect gastric emptying, intestinal motility, transit time, may absorb carcinogens |
|
|
Where does GLUT 4 act?
|
-acts in skeletal & cardiac muscle, fat cells, white blood cells
-stimulated by insulin to congregate @ membrane |
|
|
Absorption of monosaccharides in small intestine: simple diffusion
|
monosaccharides can do this, but it is rare
|
|
|
Where does GLUT2 work?
|
-liver, pancreas B cells
-not responsive to insulin |
|
|
Where does SlGLUT 1 work?
|
-intestinal epithelium, mucosal surface, kidneys
|
|
|
How does the liver regulate blood glucose level?
|
-keeps it relatively constant, except after meals, oscillating around 4.5 to 5mM
|
|
|
Effect of diabetes on blood glucoses
|
- start higher blood glucose --> go higher --> come down slower
|
|
|
How do you keep glucose in the cell? Which enzymes do this? What is an isozyme?
|
-phosphorylation
-hexokinase, glucokinase -isozyme: enzymes that are different but carry out same rxn |
|
|
Differences between Glucokinase & Hexokinase (3)
|
-Hexokinase phosphorylates other hexoses, glucokinase specific for glucose
-glucokinase restricted to liver & pancreatic cells, hexokinases are expressed everything (ubiquitos) -hexokinases inhibited by G6P, glucokinase isn't |
|
|
What is the main function of glucokinase? How is it regulated?
|
- designed for responding to blood glucose concentrations
-has a high Km so that it is not on until there is a high concentration of glucose --> way to filter it out of circulation |
|
|
Maturity-onset diabetes of the young (MODY) - subset of type II diabetes
|
-mutated glucokinase gene or genes for transcription factors
-not associated with obesity or high blood lipid levels, based on single mutation -diabetes can be dangerous b/c you can't regulate glucose levels & glucose osmotic properties -inbetween graph of normal & type II diabetes person |
|
|
How does glucokinase regulate gycolysis that regulates insulin secretion?
|
-glycolysis -->ATP controls the potassium channel--> potassium channel controls insulin secretion via calcium influx
-if mutation in glucokinase you need even more glucose to get that response |
