Flashcards in Carbohydrate Absorption, Transportation, Digestion Deck (29)
What are the major carbohydrates in the diet?
Starch, Sucrose, Lactose.
What constitutes L and D glucose forms?
OH group on asymmetric carbon farthest from carbonyl carbon is Right=D Left=L
What constitutes the Alpha and Beta configurations of glucose?
Hydroxyl group pointing down=Alpha
If a hydroxyl group on an anomeric carbon is not linked, this ring can open and be what kind of agent?
A reducing agent.
Starches are polymers of what? What are the two kinds of molecules that constitute starch?
Polymers of a-D-glucose. Amylose and amylopectin.
What kind of bonds are in amylose?
Glucose a-1,4 Glucose
What kind of bonds are in amylopectin? What is different between this molecule and amylose?
Glucose a-1,4 Glucose, and Glucose a-1,6 Glucose. This molecule can be branched (a-1,6)
What is glycogens main purpose? Polymer of what? What bonds?
1. Storage form of glucose in animals
2. Polymer of a-D-glucose
3. Glucose a-1,4 glucose, and a-1,6. Like amylopectin but more branched.
What is cellulose a polymer of? type of bonds?
Polymer of b-D-glucose. Glucose b-1,4 glucose bonds.
What molecules and bonds are not digestible?
Cellulose, Glucose b-1,4 Glucose,
What is sucrose made up of and what bonds? What kind of agent?
Glucose linked to fructose in a,b-1,2 bonds. Non-reducing agent.
What is the difference between sucrose and sucralose (artificial sweetener)?
Sucralose has replaced H with Cl.
What is lactose made up of and what bonds?
Galactose and Glucose with b-1,4 bonds.
what is trehalose made of, what bonds?Found where?
It is a Glucose a,a-1,1 Glucose bond, found in mushrooms and insect blood.
What are glycosidases?
Enzymes that hydrolyze glycosidic bonds.
What does salivary a-amylase do? Affinities?
Hydrolyzes a-1,4 interior chain bonds, with a low affinity to bonds next to branch points.
Salivary a-amylase activity on amylose produces? Amylopectin?
Amylose= Maltose, Maltotriose, Oligosaccharides
Amylopectin= Maltose, Maltotriose, a-dextrin
What are the two phases of digestion in the intestine?
Luminal and Membrane phases.
Secretin does what? Cholecystokinin?
Secretin=Causes pancreas to release bicarbonate
Cholecysto= Causes pancreas to release pancreatic a-amylase.
What does Lactase activity do?
Cleaves b-1,4 bonds in lactose
What does Trehalase activity do?
Cleaves a,a-1,1 bonds in trehalose.
What does glucoamylase complex activity do?
Cleaves a-1,4 bonds starting from non-reducing ends.
What does Sucrase-isomaltase activity do?
Sucrase=Hydrolyzes sucrose and maltose
Isomalase=Hydrolyzes a-1,6 bonds and maltase.
What are the benefits of soluble dietary fiber?
1. Reduces colon cancer
2. Pectins lower cholesterol by binding bile acids
3. Pectins slow rate of glucose absorption
4. Soften stool
5. Help irritable bowel syndrome
What is an example of a sodium-dependent transporter? What does it do?
SGLT-1. Transports Galactose and Glucose in intestine.
SGLT-2: Transports glucose in Kidney
What are the 5 GLUT transporters and what is the tissue distribution/what do they do?
1=Red blood cells, cells with barrier functions
2=Liver, transports all three monosaccharides
3=neurons, transporter in CNS
4=Adipose skeletal and heart muscle. Insulin sensitive
5=Intestinal epi cells and sperm, Fructose transporter
Where is SGLT-2 found?
What is the glycemic index based on? What do the numbers mean?
50 g of barbs to 50 g of glucose. Measures how fast you see a change in blood glucose levels, higher is faster.