- apply to facilitated diffusion and primary and secondary active transport:
1. Stereospecificity. For example, D-glucose (the natural isomer) is transported by facilitated diffusion, but the L-isomer is not. Simple diffusion, however, would not distinguish between the two isomers because it does not involve a carrier.
2. Saturation. The transport rate increases as the concentration of the solute increases, until the carriers are saturated. The transport maximum (Tm) is analogous to the maximum velocity (Vmax) in enzyme kinetics.
3. Competition. Structurally related solutes compete for transport sites on carrier molecules. For example, galactose is a competitive inhibitor of glucose transport in the small intestine.
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Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...