BIO 1130 Lecture Notes - Lecture 18: Passive Transport, Facilitated Diffusion, Membrane Transport Protein

• School: University of Ottawa
• Department: Biology
• Course: BIO 1130
• Professor: Gambarotta Sandro

Document Summary

Passive membrane transport: hydrophobic nature of membranes restrict free movement of many molecules and substances essential for life. Passive transport: movement of a substance across a membrane without the addition of chemical energy (ex: use of atp: che(cid:373)i(cid:272)al e(cid:374)erg(cid:455) is(cid:374)"t used, passive transport is driven by diffusion. Diffusion: net movement of a substance from high to low concentration: primary mechanism of solute movement within a cell and between cellular compartments separated by a membrane, rate of diffusion depends on the concentration. If difference is low the rate is slow: concentration gradient, driving force of diffusion is the increase in entropy, equilibrium is the max entropy state. Simple diffusion: passive transport of substances across lipid portion of membranes with their concentration gradients: small uncharged molecules move rapidly. Large or charged molecules may be strongly impeded from crossing the membrane: to large and the cant be moved using passive transport.