Is GLUT2 facilitated diffusion?
The GLUTs transport glucose across the plasma membrane by means of a facilitated diffusion mechanism.
Is GLUT2 active or passive transport?
There are several glucose carriers, designated GLUT1, GLUT2, GLUT3 and GLUT4. Glucose can cross the membrane in either direction using this carrier, and the direction of net transport is always down the concentration gradient for glucose because this is passive transport.
How does the GLUT2 transporter work?
GLUT2 is the major glucose transporter inβ -cells of pancreatic islets and hepatocytes. In both cell types, GLUT2 mediates the facilitated diffusion of glucose across the cell membranes, and then intracellular glucose metabolism is initiated by the glucose-phosphorylating enzyme, hexokinase IV or glucokinase.
What type of transporter is GLUT2?
facilitated glucose transporter
Glucose transporter 2 (GLUT2) also known as solute carrier family 2 (facilitated glucose transporter), member 2 (SLC2A2) is a transmembrane carrier protein that enables protein facilitated glucose movement across cell membranes.
Does facilitated diffusion require energy?
Facilitated diffusion takes place due to a difference in concentration on both sides of the membrane, in the direction of the lowest concentration, and does not require energy.
Does facilitated diffusion require a membrane protein?
In cells, some molecules can move down their concentration gradients by crossing the lipid portion of the membrane directly, while others must pass through membrane proteins in a process called facilitated diffusion.
How does sodium independent glucose transporter ( GLUT ) work?
2. SODIUM-INDEPENDENT GLUCOSE TRANSPORTERS (GLUT): GLUT – Family of closely related proteins spanning the cell membrane 12 times. – Acts via facilitated diffusion of glucose across the cell membrane. – Passive process down the concentration gradient.
What is the transport capacity of GLUT2 in beta cells?
The transport capacity of GLUT2 is in excess of the glucokinase trapping reaction, thus making phosphorylation of glucose the rate-limiting step for glucose uptake in hepatocytes and beta cells.
Which is a Class I facilitative glucose transporter?
The GLUTs transport glucose across the plasma membrane by means of a facilitated diffusion mechanism. Class I facilitative glucose transporters Class I facilitative glucose transportors are represented by GLUT1 to GLUT4, among which GLUT2 is expressed mainly in beta cells of the pancreas, liver and kidney.
Why is GLUT2 not required for glucose absorption?
Hydrogen breath tests were conducted on one patient with a nonfunctional GLUT2 protein where no defects in either glucose or galactose absorption were observed ( 59 ). This indicates that GLUT2 is not required for intestinal sugar absorption, and that another pathway is involved in the exit of glucose from the enterocyte (see Fig. 64-1 ).
