GLUT transporters

Question 1

They’re a family of glucose (hexose) transporters allow passive diffusion of glucose down its concentration gradient on the other side, through the basolateral membrane of enterocytes, and are also important for transport in other cell types.
They include:

GLUT 1
GLUT 2
GLUT 4
GLUT 5

Answer 1

GLUT transporters

Question 2

It's constitutively expressed in the brain, erythrocytes, and other cells, and allows for constitutive uptake of glucose in these cells regardless of the blood levels. In diabetic hyperglycemic state high concentrations of gluc flood neurons and erythrocytes through \_\_\_ damaging these cells and leading to diabetic neuropathy and erythrocyte dysfunction, respectively. 
What GLUT transporter is it?
A. GLUT 1
B. GLUT 2
C. GLUT 3
D. GLUT 4
E. GLUT 5
F. SGLTs 1 and 2

Answer 2

A. GLUT 1

Question 3

It’s a low-affinity transporter that allows for transport of glucose at high concentrations. It’s present on the basolateral membrane of enterocytes and allows the glucose that was taken up by SGLT1 to diffuse into the interstitial fluid and ultimately to the blood. It’s also present in the liver and pancreas, where it predominantly allows influx during states of high blood glucose to induuce glycogen synthesis and insulin release respectively in these two tissues.

What GLUT transporter is it?
A. GLUT 1
B. GLUT 2
C. GLUT 3
D. GLUT 4
E. GLUT 5
F. SGLTs 1 and 2

Answer 3

B. GLUT 2

Question 4

It’s the insulin sensitive glucose transporter that is present in skeletal muscle and adipose tissue. It’s generally sequestered in cytosolic vessels. Insulin signaling activates PI3K, which causes vesicles containing ____ to fuse with the plasma membrane, allowing for increased glucose transport. These tissues predominantly take up glucose when insulin levels are high, but alternative pathways such as activation of AMPK may also induce ___translocation to the plasma membrane.

What GLUT transporter is it?
A. GLUT 1
B. GLUT 2
C. GLUT 3
D. GLUT 4
E. GLUT 5
F. SGLTs 1 and 2

Answer 4

D. GLUT 4

Question 5

It’s a fructose transporter.

What GLUT transporter is it?
A. GLUT 1
B. GLUT 2
C. GLUT 3
D. GLUT 4
E. GLUT 5
F. SGLTs 1 and 2

Answer 5

E. GLUT 5

Question 6

Firstly, the Na+/K+ ATPase pump on the basolateral membrane of the proximal tubule cell uses ATP to move 3 sodium outward into the blood, while bringing in 2 potassium. This creates a downhill sodium gradient inside the proximal tubule cell in comparison to both the blood and the tubule. The __proteins use the energy from this downhill sodium gradient created by the ATPase pump to transport glucose across the apical membrane against an uphill glucose gradient. Therefore, these co-transporters are an example of secondary active transport. (The GLUT uniporters then transport the glucose across the basolateral membrane, into the peritubular capillaries.) Both of them are known as symporters, since both sodium and glucose are transported in the same direction across the membrane.

What GLUT transporter is it?
A. GLUT 1
B. GLUT 2
C. GLUT 3
D. GLUT 4
E. GLUT 5
F. SGLTs 1 and 2

Answer 6

F. SGLTs 1 and 2