BIOL 1020 Lecture Notes - Membrane Structure, Unsaturated Hydrocarbon, Alkane
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BIOL 1020 Full Course Notes
Verified Note
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Document Summary
Life at the edge: the plasma membrane is the boundary that separates the living cell from its surroundings, the plasma membrane exhibits selective permeability, allowing some substances to cross it more easily than others. Cellular membranes are fluid mosaics of lipids and protiens: phospholipids are the most abundant lipid in the plasma membrane, phospholipids are amphipathic molecules. Both hydrophilic and hydrophobic: the fluid mosaic model states that a membrane is a fluid structure with a "mosaic" of various protiens embedded in it. Cholesterol: a steroid with different effects on membrane fluidity at different temperatures, at warm temperatures (such as 37 celsius), cholesterol restrains movement of phospholipids, at cool temperatures, it maintains fluidity by preventing tight packing. Attachment to the cytoskeleton and extracellular matrix. Animal cell junctions extracellular fluid: tight junctions, membranes of neighboring cells are pressed together, preventing leakage of, desmosomes (anchoring junctions) fasten cells together into strong sheets, gao junctions (communicating junctions) provide cytoplasmic channels between adjacent cells.
