KAAP309 Lecture Notes - Lecture 2: Resting Potential, Electrochemical Gradient, Fluid Compartments
2 Mar 2016
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Document Summary
Plasma membrane structure: bimolecular layer of lipids and proteins in a constantly changing fluid mosaic, plays a dynamic role in cellular activity, separates intracellular fluid from extracellular fluid, interstitial fluid= ecf that surrounds cells. Passive transport: no atp used, substance moves down its concentration gradient. Simple (lipid-soluble molecules: non-polar lipid soluble substances diffuse directly through the phospholipid bilayer, ex. Glucose into cells) use carrier proteins or channel proteins in order to move around the cell. Carriers: this is done via a protein carrier specific for one chemical, binding of substrate causes a change in shape in the transport protein. Channels: through a channel protein, mostly ions selected on basis of size and charge. Osmosis: diffusion of water, through aquaporin channels. Isotonic: solution with the same solute concentration as the inside of a normal cell. Hypotonic: a solution with a lesser solute concentration than a normal cell. Hypertonic: a solution with a greater solute concentration than in a normal cell.
