FABS 210 Lecture Notes - Lecture 4: Escherichia Coli, Phosphate, Cell Membrane
16 Jan 2018
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Document Summary
Magni cation: the ability to make an object larger. Resolution: the ability to distinguish two adjacent objects as separate and distinct: differential stains: the gram stain. Highly selective permeable barrier, it enables concentration of speci c metabolites and excretion of waste product. Phospholipid bilayer-the building block of cellular membranes, it contains both hydrophobic and hydrophilic components. The phosphate-glycerol portion of the molecule is water soluble. The fatty acid portion is water insoluble. Hydrophilic region on the cell wall, the hydrophobic region is in-between the cell walls. Integral membrane protein-proteins are rmly imbedded in the membrane. Transport proteins accumulate solutes against the concentration gradient: protein anchor. Holds transport protein in place: energy conservation. Hydrophobic nature of the internal portion makes it a higher diffusion barrier. Hydrophilic and charged molecules do not pass through. Some small hydrophobic molecules can pass by diffusion. Aquaporins-form membrane channels to let the water go in and out.
