MEDN2001 Lecture Notes - Lecture 1: Signal Transduction, Cell Junction, Passive Transport
Document Summary
Integral membrane proteins attach to the extracellular matrix. Provide structural integrity to a tissue by anchoring adjacent cells. Provide direct communication between adjacent cells to permit coordinated responses to stimuli. Hydrophobic molecules and small polar molecules can diffuse through the lipid layer, but ions and large polar molecules cannot. Integral membrane proteins enable ions and large polar molecules to pass through the membrane by passive or active transport. The plasma membrane is characterised by an electrical potential (difference in net charges on the two sides of the membrane is called the membrane potential mv) is maintained by regulating the concentrations of key ions. Changes in the membrane potential are used by cells to code and transmit information. If some event, such as the opening of a gated ion channel, causes the membrane potential to become less negative, this is termed depolarisation.
