BISC305 Lecture Notes - Lecture 7: Cell Membrane, Sphingolipid, Phospholipid
19 Mar 2019
School
Department
Course
Professor
MPN
Tuesday 3/5/19
Exam: every question is worth 3 points
→ increasing Numerical Aperture (electron)
Practice questions at the end of each chapter section & assigned practice questions
→ saturated vs. unsaturated of parts of lipid structure
• Structure & Function of Plasma Membrane (composition of plasma membrane)
o Asymmetric membrane-proteins/glycoproteins, phospholipids/glycolipids
o Carbohydrates-always pointing to extracellular environment
▪ Communication: Cell-to-cell recognition
▪ Protection: for internal cell; things that can damage proteins and lipids, acting as shield
• Proteins-secreted from cell contain multiple carbohydrates in order to protect
them, in order to not be broken down
o Lipids: cholesterol, phospholipids, sphingolipids
o Proteins: integral membrane proteins, peripheral membrane proteins (associated with internal or
external side of membrane)
▪ Types of proteins: receptor, transporter, enzyme, anchor proteins
• Transporter: carrier, channel
• Receptor: bind to ligand and initiate signals
• Enzyme: catalyzes reactions
• Anchor: anchor peripheral membrane proteins
o Fluid-Mosaic Model-lipids and proteins coexist in the membrane, forming a “mosaic”
▪ Molecules move with other pieces
▪ Lipid rafts-lipids move together on plasma membrane; membrane domain
▪ “too stiff”-movement restricted, transport & permeability restricted
▪ “too fluid”-too much enters cell, not able to stay compact and organized, shape and
structure
• Permeability
o Partition coefficient-property of dissolving in organic solvents rather than water
▪ Membrane components
▪ Greater the solubility, greater the coefficient
