BIOL107 Lecture 6: Cell Membranes
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BIOL107 Full Course Notes
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Biol 107 - lecture 6 - cell membranes. The amphipathic nature allows phospholipids to spontaneously form membranes. They spontaneously form these bilayers because they are amphipathic and because they are columnar and can fit together easily. Micelles (circular shaped membranes) are formed by single tail phospholipids. They can move around freely laterally within the same place of the membrane because they are only associated based hydrophobicity and not covalent bonds. This means that lateral movement occurs rapidly. Flip/flop movement is very rare because the hydrophilic head would have to pass through the hydrophobic core of the membrane on. The fluidity of the membrane is crucial to the normal functioning of the membrane. Temperature and membrane composition can affect fluidity. As temperature increases the spaces between them increases. If the kinks are removed, the phospholipids can fit closer together and therefore reduce permeability. Cholesterol acts as a barrier to phospholipid movement. Forces phospholipids to move around the choleserol.