BIOL 2410 Chapter 3: Chapter 3 Human Physiology Part 2
29 Mar 2018
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Document Summary
Membrane lipids create a hydrophobic barrier three lipids that make up many membranes: phospholipids, sphingolipids, and cholesterol. Sphingolipids: have fatty acid tails but their heads may be either phospholipids of glycolipids: also slightly longer than phospholipids. Cholesterol: important part of membranes, mostly hydrophobic, they insert themselves between the phospholipid heads: makes membranes impermeable to small water-soluble molecules and keeps membranes flexible during temperature changes. Membrane proteins may be loosely or tightly bound to the membrane. Integral proteins: tightly bound to the membrane but not covalently bound, only way to be removed is disrupting membrane structure harshly. Peripheral proteins: attach to other membrane proteins by noncovalent interactions, can be removed without disrupting the structure. Membrane carbohydrates attach to both lipids and proteins. Glycocalyx: protective layer on the outside of the cell composed of carbohydrates attached to lipids or proteins. Glycoproteins play a major role in the immune system. Differentiation: selected genes become active, transforming the cell into a specialized unit.
