PSL300H1 Lecture Notes - Lecture 1: Atp Hydrolysis, Membrane Transport Protein, Facilitated Diffusion
Document Summary
Psl 300 - human physiology - fall 2019. Cell membranes are made up of a semi permeable phospholipid bilayer. If a molecule can bypass the membrane by any means, the membrane is said to be permeable to the molecule. Lipid-soluble molecules and gases can pass through easily. Water-soluble molecules and negatively charged organic anions cannot pass through without help. Solubility depends on the size of the molecule, the charge of the molecule, and the molecule"s lipid solubility. Simple diffusion: passive movement of molecules down a concentration gradient, from an area of high concentration to an area of low concentration. The rate of diffusion depends on the relative concentrations of the molecule. Can be through the membrane directly or through continuous pores. Facilitated diffusion: passive movement of molecules down a concentration gradient, from an area of high concentration to an area of low concentration.
