A patch of alveolar cell membrane has permeability to oxygen

PHYSICS · Multi-part · Fermi University Physics · Biophysics & Medical Physics · Molecular machines, transport and bioenergetics · Molecular machines, transport and bioenergetics

Life at Thermal Energy, Ch The membrane: barrier, capacitor and pump

Problem

A patch of alveolar cell membrane has permeability to oxygen Ps=2.0×10−4 m s−1P_{\rm s} = 2.0\times10^{-4}\,\mathrm{m\,s^{-1}}. The patch has area 100 μm2100\,\mathrm{\mu m^2} and separates two well-stirred compartments whose oxygen concentrations differ by Δc=0.10 mM\Delta c = 0.10\,\mathrm{mM}, a difference that stays constant while you calculate. Treat the membrane as a flat slab and assume steady state. ((a)) Find the flux density JJ of oxygen through the patch. ((b)) Find the number of oxygen molecules crossing the patch per second.

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