Page 25 - BIOCHEMISTRY II
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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
