Lecture 3 Flashcards
what is the plasma membrane also called
fluid mosaic model
what’s the must abundant lipid in the plasma membrane
phospholipid
where do phospholipids move in the plasma membrane?
within the bilayer
what are flippase and floppase
enzymes that move things between the two inlets
what does flip flop signify and how often does it happen
tells other cells that it is dying and is ready to be digested, 1 a month
are membranes rich in unsaturated fatty acid or saturated fatty acid more fluid
unsaturated
when cholesterol is in a warm temperature, what happens?
it restrains the movement of phospholipids
what is a membrane?
a collage of different proteins embedded in the fluid matrix of the lipid bilayer
what are the six major functions of membrane proteins ?
Transport
enzymatic activity
signal transduction
cell-cell recognition
intercellular joining
attachment to the cytoskeleton and ECM
Passive transport ?
diffusion
facilitated diffusion
why is facilitated diffusion passive?
even though it needs a transporter protein present, it is still going from a high concentration to a low concentration gradient
Active transport?
Primary and secondary
what are the three types of movement across membranes?
passive transport
active transport
exocytosis and endocytosis
what is diffusion
tendency for molecules to spread out evenly into available space. substance moves down the concentration gradient.
Osmosis is what gradient
low to high
what is osmosis
the diffusion of water across a selectively permeable membrane
what is tonicity
the ability of a solution to cause a cell to gain or lose water
What do channel proteins do in facilitated diffusion
provide corridors that allow specific molecules or ion to cross the membrane
what does a carrier protein do in facilitated diffusion
they change shape subtly that translocates the solute binding site across the membrane
what are microtubules made of?
protein called tubulin, dynein, kinesin
What energy is used in active transport?
ATP
what cell is the sodium potassium pump in? is it active or passive transport
animal cells, active transport
how many sodium and how many potassium go through a sodium potassium pump
3 Na and 2 K
what are the three classes of transporters for active transport
uniport
symport
antiport
