Inside of cell Outside of cell Carrier proteins allow glucose to enter a cell at a faster rate than would be possible by simple diffusion across the membrane barrier. Glucose carrier protein Glucose Figure 5.11 A Carrier Protein Facilitates Diffusion

The carrier protein has a glucose binding site. Inside of cell Outside of cell Glucose Figure 5.11 A Carrier Protein Facilitates Diffusion

Glucose Glucose binds to the protein... Inside of cell Outside of cell Figure 5.11 A Carrier Protein Facilitates Diffusion

Inside of cell Outside of cell Figure 5.11 A Carrier Protein Facilitates Diffusion

...which then changes its shape... Inside of cell Outside of cell Figure 5.11 A Carrier Protein Facilitates Diffusion

...releasing the glucose. Inside of cell Outside of cell Figure 5.11 A Carrier Protein Facilitates Diffusion

The carrier protein then goes back to its original shape, ready for another glucose. Inside of cell Outside of cell Figure 5.11 A Carrier Protein Facilitates Diffusion