Lecture 2-Membrane Transport Flashcards
Kinetic energy
The energy of movement. It is also related to thermal energy. ^ thermal energy = ^ kinetic energy. ^ KE also produces ^ TE.
What is “diffusion?”
The movement of a solute down its [ ] gradient from high to low. Does not require any transport mechanisms (like channels)
Describe osmosis
The movement of a solvent (usually water) down its concentration gradient so it will dilute a high [solute].
What is the formula for osmotic pressure?
(g)x(c)xRT
g=particles in slxn (osm/L)
c= [ ] (mol/L)
RT= gas constant x temperature
What is “Effective osmotic pressure?”
The osmotic pressure as determined by how permeable a membrane is to a given ion. (Eff. Osm. P= δ×π)
What is δ?
The “reflection coefficient.” It is a measure of permeability and, therefore, how much an ion contributes to osmotic pressure.
List the E* independent forms of cellular transport.
Osmosis, diffusion, facilitated transport.
What do the E* independent types of transport require?
Some type of carrier protein.
What is the main difference between primary and secondary active transport?
WHEN ATP is used for energy.
What 3 factors affect rates of diffusion?
Concentration differences, pressure differences, electrical potential (Nernst equation)
What 3 factors increase plasma membrane permeability and, therefore, increase diffusion?
Increased lipid solubility, decreased P.M. thickness, decreased solute size
What is the equation for measuring diffusion?
J=PA(Co-Ci)
P=permeability
A= area
C
What are the two types of molecular movement?
Thermal & kinetic
