Lecture 10-Transport across biological membranes I (March 25).pdf

BIOC*4580 – Membrane Biochemistry Winter 2024 Module 4 - Transport Processes Overview + Diffusion & Facilitated Diffusion Summary of types of membrane transport nonpolar compounds can dissolve in the lipid bilayer and cross a membrane unassisted polar compounds and ions require a specific membrane p...

BIOC*4580 – Membrane Biochemistry Winter 2024 Module 4 - Transport Processes Overview + Diffusion & Facilitated Diffusion Summary of types of membrane transport nonpolar compounds can dissolve in the lipid bilayer and cross a membrane unassisted polar compounds and ions require a specific membrane protein carrier Simple Diffusion Differs from osmosis, goes down concentration gradients ΔG for uncharged solutes depends on concentration difference (C1-C2) Free energy change for transport of 1 mole of uncharged solute from concentration C1 to C2: ΔG = RT ln (C2/C1) R = 8.315 × 10-3 kJ.mol-1.K-1 T = temperature (in °K) passive transport → DOWN concentration gradient: – C1 > C2, C2/C1 < 1, ΔG = ΔG0′ + RT ln ([P]/[S]) – so ΔG