Question

Erythrocytes (red blood cells) swell or shrink rapidly in response to changes in the osmolarity of the blood by the movement of water molecules through plasma membrane channels called aquaporins (AQP). AQP1 is a tetramer that consists of four identical monomers, each of which has a transmembrane pore. A human erythrocyte has approximately 2.0 x 10° AQP1 monomers and a total volume of 9.4 x 10-" mL Water molecules flow through the plasma membrane at a rate of 5.0 x 108 molecules per AQP1 tetramer per second. Calculate the number of water molecules in an erythrocyte. Assume that the erythrocyte consists entirely of water. number of water molecules: 2.5 x1013 water molecules Calculate how rapidly an erythrocyte could halve its volume when it encounters the high osmolarity (1.0 M) in the interstitial fluid of the renal medulla. seconds time: 3.34 x10-2

Answer 1

page: 0 Answen According to the given in for mation, - to find the - following problems, Given, human erythrocyte total volume - 9-uxtó" md. Denility of water a igled volume of caten -9.62x10mm.. mest ogwater - q.uxto'g.: mola, mans of water = 18 glmol. number of rape stetramers eg.0x10slu 5-oxid" -flow thorought the plasma mombrane at a gate = 50x108 : molecules per Aapi tetramenols calculate number of coaten molecules :- * het, moles of water a queixió"z 801

page:02 Number of water molecules z moles of water x Alvagardo No. then, moler of water = mass of water (molar mass of water = quxlohg 118g Imol moles of water. = 5oaxiola mol Avagando numben - 6.024x1093/mol then, Number of water molecules : S• axioma mot x 6082 x18 %! 1. = 3015x102 .number of water molecules = 3.15X106 water molecules * calculate time taken to have volume of an erythrocyte: beli Number of Aapi tetramers = sooxiou water molecules flow through the plasma membrane! at a rate = S:0X108 moleculeri aapt tetrameten -- second. goi

page:03 time taken to have volume of an erythrocyte : 0.5 (3.15 x10 neoleuter Sooxiou naft te tre mens x Soxio mokeulen napitetramerele 205x / 315x10 seconds) (sxio x5*108 ) 2015 x 3.15x1012 seconds) y (das xido : 2015* 0196 seconds = 0.063 seconds, . time = 0.063 seconds