UNIT 5: CARBS - digestion Flashcards
1
Q
The salivary gland secretes a-amylase to
A
- hydrolyze a-1-4 glycosidic bonds
- break down maltose to a-dextrins
2
Q
What is the glycocalyx?
A
- outermembrane of small intestine covered by glycoprotein and mucopolysaccharides
3
Q
What is the function of the glycocalyx?
A
- enhances functional surface area, allow nutrients to diffuse in, cleave absorbable units, close proximity to membrane
4
Q
When there is still glycogen left in cell and a-1-4 linkages are digested first, what happens to the free glucose and a-1-6 glucose?
A
a-1-6 glucose leftover is called isomaltose/alpha-dextrinase
- this is targetted by isomaltase
- cleave a-1-6 linkage to yield 2 new glucose molecules
5
Q
What are the 3 required enzymes to digest all starch and glycogen in diet?
A
- a-amylase
- maltase (glycocalyx linked)
- alpha-dextrinase/isomaltase
6
Q
What happens when someone who does not express lactase consumes lactose?
A
- lactose disaccharide will draw water into lumen
- pass intact into the colon
- bacterial fermentation occurs
- produces gases, organic acids, increased gut motility (irritation)
7
Q
SGLT-1 Sodium Glucose Transport 1
A
- controls absorption of glucose and galactose
- Na+ pump requires ATP
- 2 Na+ for each 1 glucose or galactose
- co-transporters and active transport
8
Q
GLUT-5
A
fructose transporter
- down conc. gradient (lumen to mucosal cell)
- facilitated diffusion
9
Q
GLUT-2
A
transporter for all sugars
- basolateral membrane of enterocyte
- facilitated diffusion / passive diffusion
- mucosal cell to blood stream
