Lecture 5 - Digestion and Absorption of Carbohydrates Flashcards
In the oral cavity, a-amylase is an ___________ that randomly cleaves internal a(1-4) glucosidic bonds.
endoglucosidase
Chyme moves through the duodenum into the small intestine to stimulate the release of _____ and _____.
secretin and CCK
Where does the pancreatic phase of carbohydrate digestion occur?
lumen of the small intestine
Where does the disaccharidase phase of carbohydrate digestion occur?
mucosal brush border cells
Cholecystokinin (CCK) stimulates the release of:
pancreatic a-amylase (and other digestive enzymes) that cleaves a-(1,4) glucosidic bonds
3 products generated by a-amylase in the small intestine are:
- maltose
- glucose
- limit dextrins
Which is NOT a product generated by a-amylase in the small intestine?
A. Maltose
B. Glucose
C. Maltase
D. Limit dextrins
C - Maltase is a disaccharidase embedded in the glycocalyx
___________ is an a-glucosidase that hydrolyzes maltose to 2 molecules of glucose.
A. Lactase B. Maltase C. Maltosase D. Dextrinase E. Sucrase
B
_______ is a B-galactosidase that cleaves lactose to galactose and glucose.
A. Lactase B. Maltase C. Maltosase D. Dextrinase E. Sucrase
A
What is the function of Mucin secretion by Goblet Cells?
provides a protective coating for the disaccharidases
______ transports glucose and galactose from the lumen into the intestinal mucosal cell.
A. SGLT1 B. GLUT5 C. GLUT2 D. GLUT4 E. GLUT3
A
_______ transports fructose from the lumen into the intestinal cell.
A. SGLT1 B. GLUT5 C. GLUT2 D. GLUT4 E. GLUT3
B
________ transports all 3 hexoses from the intestinal cytosol into the portal circulation.
A. SGLT1 B. GLUT5 C. GLUT2 D. GLUT4 E. GLUT3
C
Carbohydrates are absorbed from the intestinal lumen in the:
upper jejunum
Which is NOT located in the brush border membrane?
A. SGLT1
B. GLUT5
C. GLUT2
C - GLUT2 is located in the basolateral membrane
Which glucose transporter in the GLUT family has the highest affinity and rate of transport for glucose?
GLUT3 - supplies energy to the brain even at low blood glucose levels
Which glucose transporter is stimulated by insulin?
GLUT4 - enriched in fat cells, skeletal muscle, heart muscle
Which glucose transporter has a low affinity and high capacity for glucose transport?
GLUT2 - enriched in hepatocytes, pancreatic B-cells, kidney, and the basolateral membrane
Which glucose transporter is enriched in red blood cells and endothelial cells of the blood brain barrier?
GLUT1
3 diagnostic tests for lactose intolerance include:
- Direct Assay for Enzyme
- Blood Glucose after Lactose Load
- Hydrogen Breath Test after Lactose Load
