cells 3 Flashcards
What is the plasma membrane? what does it do?
-in eukaryotic cell and organelles
-regualates substance movement
-partiallu permeable(some molecules not all)
What is meant by the term fluid mosaic?
-arrangment of molecules
-fluid- constanlty moving
What is the arrnagment of phospolipids in the bilayer?
what do they do?
-only allow non polar molecules to pass through
-phophate head-exterior
-hydrocarbon tails-interior
What is cholesterol? what does it do?
-lipid
-restricts movement/fluidity
-maintain cell shape
what are the 2 types of protiens and what is their structure?
intergal-span the bilayer
peripheral-dont span bilayer
what do peripheral protiens do?
-create receptors(glycolipids and glycoprotiens)
-mechanical support
what do intergral protiens do?
-carrier and channel protiens
-allow polar large molecules to enter the cell
function and structure of channel protiens
-contain water
-allow polar moelcules to diffuse through
funstion and structure of channel protiens
-binds to the large molecules, changes shape to transport, and release on the other side
properties of the cell membrane
-receptors for hormone signals
-reguakting solute movement
-identifiying solutes
-isolating cell from outside environment
-providing cell structure
What is simple diffusion and where does it happen?
-passive
-for small non polar molecules
-through the fatty acid tails
what is faciliated diffusion and where does it happen?
-passive
-large polar molecules
-through intergral protiens
Definition of diffusion?
-the net movement of molecules between an area of higher concentration to an area of lowe concentration down a concentration gradients until equilibrium is reached
Things that effect diffusion
-size of molecule
-size of concentration gradient
-amount of intergal protiens
-diffusion distance
-temperature
What is the definition of osmosis
- the movement of water from an area of a higher water potential to lower water potential across a partially permeable membrane
what is the sign for water potenital? waht the is measurement for water potential
-see book and kPa
what is the water potentail for pure water?
-zero
what happens when solutes become dissolved in water?
-it becomes negative- lower water potential
What does isotonic mean?
the waterpotential in the cell and the solution is the same
what does hypertonic mean and what happens?
when the water potential in the solution is more negative that in the cell ( cell will shrivel up)
what is hypotonic and what does it mean?
-when the water potential in the solution is higher than inside the cell- cell will swell and burst
why do cells bot burst in plant cells ?
-beacuse of their cell wall
What is the definition of active transport?
-The net movement of molecule from a reigon of lower concentration to a reigon of higher concentration using ATP and carrier protiens
what happens in active transport?
-molecule binds to the complementary recptors on a protiens
-ATP binds to the carrier protien
-ATP is hydrolyised in ADP+PI
-the phosphate group stays of the carrier protien- the energy causing the carrier protien to change shape
-molecule is released, phosphate leaves and protien turns back into its orignial shape
