课件-国外大学细胞生物学课件-英文3.bioy.ppt

Common fatal genetic disease Phenotype: thick, sticky mucus ?respiratory congestion ?breeding ground for infection-causing bacteria ?blocks pancreas function Cystic Fibrosis is caused by mutations in CFTR, an anion channel in the apical surface of epithelial cells of the lung, pancreas, intestine and sweat glands. Mutations lead to disruption of fluid secretion into the lung (sticky mucus that cannot be cleared Early sign of the disease: saltiness of skin because fluid secretion works in conjunction with other ion transporters in epithelial cells. * Cystic Fibrosis W2011 D103 Cell Biology - lecture 3 ? Suetterlin and MacGregor - all rights reserved. * Important concepts, lecture 3 Molecule transport across a membrane is mediated by transmembrane proteins Carriers/transporters (eg GLUT1) high specificity, saturable active and passive transport is possible Undergo conformational change during the transport of molecules Pumps/ATPase (MDR-1)? energy from ATP hydrolysis is converted into mechanical work such as ion transport against their electrochem. gradient) Ion channels (see lecture 4) Directions of transport: Transport down the electrochemical gradient is passive and does not require energy Transport against the electrochemical gradient requires energy ATP hydrolysis (Na/K pump), light-driven) “ride along” (syn- and antiport) taking advantage of the potential energy of other molecules. membrane potential: voltage difference across a membrane which is due to a slight misbalance of ions. W2011 D103 Cell Biology - lecture 3 ? Suetterlin and MacGregor - all rights reserved. * * * * * * * * * * * * * * * * * * * * * W2011 D103 Cell Biology - lecture 3 ? Suetterlin and MacGregor - all rights reserved. W2011 D103 Cell Biology - lecture 3 ? Suetterlin and MacGregor - all rights reserved. W2011 D103 Cell Biology - lecture 3 ? Suetterlin and MacGregor - all rights reserved. W2011 D103 Cell Biology - lecture 3 ? Suetterlin and MacGregor - all rights reserved.