BIOC40H3 Lecture Notes - Lecture 4: Endodermis, Stoma, Peptide
14 Feb 2013
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Document Summary
The biologically regulated movement of molecules and ions from one location to another is known as transport. Plants exchange solutes with their environment and among their tissues and organs. Both iocal and long-distance transport processes in plants are controlled largely by cellular membranes. Transport must occur across the plasma membrane, which is a thin layer of two lipids (lipid bilayer, each layer is hydrophilic towards the outside and hydrophobic towards the inside, forming a hydrophobic barrier to diffusion) The plasma membrane also detects information about the physical environment, about molecular signals from other cells, and about the presence of invading pathogens and often relays these signals by changes in ion flux across the membrane. Passive transport is spontaneous movement (diffusion) of a solute across a membrane in the direction of a gradient of electrochemical potential (from higher to lower potential), also known as downhill transport.
