Carbohydrate Absorption, Transportation, Digestion Flashcards
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
Pointing up=Beta
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?
- Storage form of glucose in animals
- Polymer of a-D-glucose
- 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?
- Reduces colon cancer
- Pectins lower cholesterol by binding bile acids
- Pectins slow rate of glucose absorption
- Soften stool
- Help irritable bowel syndrome
