Membranes and transport Flashcards
What are the functions of a membrane
-Separate cells from the external medium to create a unique intracellular environment
-allow selective transport of substrates in and out of the cell
-Provide a location for specialized pathways and proceses (eg. energy conversion of mitochondria)
-Rapid changes in electrical potential across the membrans of neurons as basis of the nervous system
-Localization of receptors to facilitate response to physiological signals
-Mediate cell-cell recognition and interaction
What are the characteristics of membranes
Describe the formation of membranes
How are vesicles used for drug delivery?
Describe permeability in membranes
Describe membrane composition
-Membranes are primarily composed of lipids and proteins
-More active membranes have a higher ratio of protein to lipid
-Composition of membrane components can be dynamic, particular for prokaryotes
What is the relationship between temperature and lipids?
-Too high temp destroys lipids
-They function 10-20 degrees above transitional melting temperature
-Favours dynamicism
What type of bonds lower transitional melting temp?
-Increased cis-double bonds (unsaturated)
-More dynamic and flexible
Explain the fluid mosaic model of membrane structure
-Membranes are dynamic structures due to the nature of the non-covalent interactions
-Lipids and proteins freely diffuse in the plane of the membrane
-Lateral movement of proteins and lipids within the membrane is very rapid
-Movement across the membrane is restricted
Explain transbilayer movement
Describe membrane fluidity
What are lipid rafts?
What are membrane proteins and the 3 categories?
What are peripheral membrane proteins?
What are lipid-anchored membrane proteins?
What are integral membrane proteins?
Describe hydrogen bonding within membrane-spanning regions
What is the distribution of amino acids in integral membrane proteins?
What are the categories of membrane transport?
-Simple diffusion
-Facilitated diffusion (carriers and channels)
-Active transport (primary and secondary)
-Ion transporters
What is simple diffusion?
What is facilitated diffusion? channels vs carriers
What is coupled transport?
What is active transport? primary vs secondary
What is P-Type ATPase?
