Lecture 6 Learning Objectives Flashcards
Singer and Nicholson model of plasma membrane
Fluid mosaic model
Phospholipids in outer leaflet
Cholesterol Glycolipids Sphingomyelin Phosphatidyl Choline Glycosylphosphatidyl inositol
Phospholipids in Inner leaflet
Cholesterol
Phosphatidyl inositol
Phosphatidyl ethanolamine
Phosphatidyl serine (negative charge)
Where are glycolipids located in the plasma membrane
Only on outer leaflet
Imparts antigenicity to cell
Lipid Raft Functions
Compartmentalize cellular processes Assembly of signal molecules Influence membrane fluidity Membrane protein trafficking Regulates neurotransmission and receptor traffic
Glycocalyx
Not integral part of membrane
Carb coat on extracellular cell surface composed to glycolipids and glycoproteins
Protects cell from ionic, mechanical stress
Barrier
Cell-to-cell communication
Peripheral proteins
Found on inner and outer leaflet - can be more easily removed than integral proteins
Integral proteins
Embedded within phospholipid bilayer - associate with the nonpolar core of the bilayer
Transmembrane
Integral proteins that pass completely through the bilayer - channel or transporter proteins
Passive transport
No energy required - may require transport molecules
Diffusion
Type of passive transport - movement of ions or molecules from high to low concentrations - no transport molecule needed
Osmosis
Diffusion of solvents across cell membranes - no transport molecule needed
Facilitated diffusion
Diffusion using transporter molecule
Active transport
Movement against a concentration gradient- requires energy and transport molecule
Uniporters
Move one molecule in one direction