Chapter 9.1 Flashcards
1
Q
Describe the general characteristics of Glut 2
A
- low affinity transporter in hepatocytes and pancreatic cells
- > Glut 2 captures the excess glucose primarily for storage
- > when the glucose [] drops below the Km of the transporter, the remainder bypasses the liver and enters peripheral circulation
2
Q
How does the high Km value of Glut 2 relate to how much glucose the liver can pick up
A
- high Km means that the liver will pick up glucose in proportion to its concentration in the blood
- > so first-order kinetics
3
Q
Describe the general characteristics of Glut 4
A
- in adipose tissue and muscle
- > responds to glucose concentration in peripheral blood
- > rate of glucose transport is increased by insulin
- > more Glut 4 transporters appear on the surface of cells
4
Q
How does the Km value of Glut 4 relate to how much glucose the transporter can take
A
- Km of Glut 4 is close to normal glucose blood levels
- this means that the transporter is saturated when blood glucose levels are higher than normal
- > therefore, these transporters will only permit a constant rate of glucose influx
- > resulting in zero order kinetics
5
Q
How does adipose tissue store glucose
A
- requires glucose to form dihydroxyacetone phosphate
- >DHAP is converted to glycerol phosphate to store incoming fatty acids as triacylglycerols