MICR 2123 Lecture Notes - Lecture 2: Electric Motor, Nuclear Membrane, Membrane Protein
28 Aug 2016
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Document Summary
Most prokaryotes share fundamental traits: thick, complex outer envelope, compact genome, tightly coordinated cell functions. Eukaryotes- have a defined nucleus with a nuclear membrane. Cell membrane- defines the existence of a cell. Membrane protein functions: structural support, detection of environmental signals, secretion of virulence factors, ion transport and energy storage, phospholipids- water-loving head and lipid-loving tail. Arranged in a bilayer with the tails facing inward towards each other. Cell membrane is semipermeable: small uncharged molecules easily permeate by passive diffusion, water passes through by osmosis, charged molecules, like sugars, amino acids, and vitamins, and ions, must pass through protein transporters. Transporter proteins help molecules cross to the cytoplasm. Passive- use the concentration gradient to go from high concentrations to low concentrations. Active- go against the concentration gradient and requires energy. Confers shape and rigidity of the cell to be able to withstand turgor pressure. Most are made up of peptidoglycan: peptides (small proteins) and glycans (sugar)
