Cell Membrane Transport

Lecture 3 chemical messengers and signaling

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Unformatted text preview: r equilibrates the internal concentration, volume increases. Cell shrinkage. Osmolarity vs. Tonicity Tonicity: determined by how it affects cell volume Isotonic, hypertonic, hypotonic Depends on the solute concentration and permeability Intracellular solutes are relatively impermeant. This is known as the osmotic drag. Transport Via Components Transport macaromolecules via membrane compartments Phagocytosis vs. Pinocytosis vs. Receptor- mediated transport Endocytosis and Exocytosis: Transcytosis These macromolecules are now part of the cell, but they still cannot diffuse out of the vesicle. Secretory vesicles have molecules made within the cell, and the contents are released. Transport Across Epithelium: Solute Transport Across 2 Membranes Basolateral Membrane Sodium/Potassium pump Potassium Channel Glucose Carrier Apical membrane: Sodium channel Sodium- linked glucose pump Low intracellular Na+ caused by outward pumping basolateral creates inward gradient for Na+, Na+ leaks across apical, transported across cell Apical secondary...
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