L2 Cell Membrane And Transport Flashcards
What are the most abundant lipids in the cell membracne
Phospholipids
Short, unsaturated hydrocarbon tails do what to membrane permeability and fluidity?
Increase it
what two properties of particles influence whether they can permeate a cell membrane without assistance?
Lipid solubility
Size
What are the two types of unassisted membrane transport?
Osmosis
Simple diffusion (either through an ion channel or right through the lipid bilayer)
What are the two types of assisted membrane transport?
Carrier-mediated
Vesicular
What are the two types of carrier-mediated transport?
facilitated diffusion
Active transport (primary and secondary)
What factors are in the numerator of fick’s equation?
Concentration gradient of substance
Surface area of membrane
Lipid solubility
What two factors are in the denominator of Fick’s equation?
Molecular weight of substance
Distance (thickness)
What is Fick’s equation used to calculate?
Net rate of diffusion of a substance across a membrane
If the membrane protein changes shape to let the substance through, what kind of transport is it?
Carrier-mediated (can be passive or active)
What are the 3 types of mechanismsm for active transport?
Uniporter
Symporter (cotransport)
Antiporter (countertransport)
What kind of transport is the Na-K ATPase pump?
Primary active transport
What kind of transport is the protein that brings glucose from lumen of intestine/nephron into the cell?
Secondary active transport
uses Na+ gradient established by Na+ K+ pump to bring glucose in with Na+. So it’s a symporter
What is the driving force for water in osmosis?
Concentration gradient
When does osmosis stop?
When the hydrostatic pressure and the osmotic pressure are equal
What is the difference between osmolarity and osmolality?
Osmolarity -mOsm/L
Osmolality- mOsm/kg
(But a L and a kg are about the same amount so these two values are essentially saying the same thing)
What it the relationship between the osmolarity of the ICF and ECF?
they are identical 290mOsm
What is effective osmolarity?
The osmolarity of NON-PERMEABLE particles in solution
This is what actually controls the movement of water
