Lipid-cholesterol bilayers are studied by means of a microscopic multi-state lattice model and Monte Carlo computer simulations. The model used is a direct extension of the Pink model for the main transition of pure lipid bilayers. Cholesterol is introduced as a bulky, rigid molecule with no internal degrees of freedom. The model is able to account for the chain melting of lipid molecules, and is expected to be valid at low cholesterol concentrations. / A minimal model for the transport of ions across membranes is used to predict the changes in the passive permeability of lipid-cholesterol bilayers for different cholesterol concentrations and different lipid chain lengths. The model assigns different probabilities of transfer to bulk, clusters and interfaces. The main assumption is that, defects due to bad packing at interfacial regions, cause the membrane to be leaky and allow the ions to permeate it. Therefore the model assigns a high probability of transfer to the interfacial regions. / A peak in the permeability is observed near the transition temperature, which is in accord with experimental data. The results show an increase in the passive ion permeability for increasing cholesterol concentration for the three systems under consideration. Also, an increase in the membrane permeability is predicted for decreasing chain length for all the cholesterol concentrations studied.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.60030 |
| Date | January 1990 |
| Creators | Corvera Poiré, Eugenia |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Physics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001224844, proquestno: AAIMM67734, Theses scanned by UMI/ProQuest. |
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