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Unformatted text preview: lumen in intestine.
-in membrane of cell is transporters shown in previous slide. at baselateral membrane, have sodium potassium channel, sodium-2cl co-transporter symport. chloride channel in apical membrane. and
aquaporins (water channel, water only diffuse to membrane at low rate. so any cell that need to transport water at high rate need aquaporin which is a protein that faciliate passive diffusion of water).
-cystic fibrosis strongly affect fitness. why isn't it eliminate? 1. the mutation is spontaneous 2. heterozygote advantage (balancing selection)-in heterozygote have diminish sensitivity to disease that cause
diarrhea. this disease work through CFTR. individual heterozygote would have diminished CFTR number that are enough for survival and not affect fitness
-more recent research suggest otherwise: Cystic fibrosis is develop against tuberculosis. the temporal and geographical distribution match: more prevalent in european than asia and african countries. Air H2O Cl- Mucus CFTR AQP P Cl- Tight
Membrane cAMP Na+ K+ K+ Interstitial
Fluid Na+ Basolateral
Membrane H2O Na+,
H2O Na+ 2Cl- K+ K+ Na+ H2O...
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- Spring '09