Page 25 - Biochemistry2 (08PB403)

Passive transport (facilitated diffusion)

• Sugars pass with concentration gradient i.e. from high
to low concentration.

• It needs no energy.
• It occurs by means of a sodium independent facilitative

transporter (GLUT5) which is a fructose transporter.
• GLUT5 allows for fructose to be transported from

the intestinal lumen into the enterocyte by facilitated
diffusion due to fructose's high concentration in the
intestinal lumen.
• Fructose and pentose sugars are absorbed by this
mechanism.
• Glucose and galactose can also use the sam25e
transporter if the concentration gradient is favorable.25