Solute Transport Flashcards
How are the phospholipids arranged in the phospholipid bilayer of cells?
with hydrophopic heads facing out of the membrane on both sides
What 2 types of proteins are found in the phospholipid bilayer?
extrinsic and intrinsic
What do intrinsic proteins act as?
pumps and ion channels
What is membrane fluidity regulated by?
cholesterol
What is the function of glycoproteins and glycolipids in the phospholipid bilayer?
identify the cell as part of the body rather than something foreign
By what process do substances move down a concentration gradient?
diffusion
What energy does diffusion use?
the kinetic energy of the solute particles
What type of gradient do charged particles move down?
electrochemical gradient
What are the two types of diffusion?
simple and facilitated
What is the difference between simple and facilitated diffusion?
simple uses no transport protein and facilitated requires a transport protein
What law does the rate of diffusion depend on?
Ficks law
What energy source does active transport use?
ATP
What gradient is solute often moved against during active transport?
concentration or electrochemical
What are the two types of active transport?
primary and secondary
What does primary active transport involve?
transport directly using ATP
what does secondary transport involve?
transport indirectly using ATP
What are the two ways solutes can be transported during secondary transport?
counter transport and co transport
What is involved in counter transport?
2 solutes are pumped across the membrane in opposite directions
What is involved in co transport?
2 solutes pumped across the membrane in the same direction
How can diffusion rates be increased?
increase in temprature, larger area for diffusion, larger concentration gradient, smaller thickness of gradient
Over what distances does diffusion occur rapidly?
microscopic
How many millimetres are there in a micron?
1000 mm
how quickly will diffusion occur over 1 micron?
0.0005 seconds
How quickly does diffusion occur over 1000 micron (1mm)?
498 seconds
What effect has the length of time for diffusion had on the evolution of mammalian bodies?
evolved bulk transport systems
What does facilitated diffusion require?
a transporter protein
What energy does facilitated diffusion use?
kinetic energy of solute particles
Why does the rate of facilitated diffusion tail off?
encounter rate limiting factor, transporter protiens are all in use so diffusion cannot happen any faster
What is the flattening of the facilitated diffusion rate known as?
saturation kenetics
What sort of proteins are ion channels?
intrinsic
What are the 3 states that ion channels can be in?
open, closed or inactivated
What is the inactivation of certain ion channels known as?
gating
What is the difference between specific and non specific ion channels?
non specific will allow any ions through whereas the specific is more selective
What does active transport require?
ATP
What is the energy from ATP used to do?
move solutes against the concentration gradient by phosphorylation and altering the shape of the protein
What sort of protien channels does active transport use?
intrinsic proteins
What can the process of active transport be stopped by?
metabolic poisons e.g. cyanide
During active transport how many sodium ions are pumped out and how many potassium ions pumped in?
3 Na out and 2 K in
What is the benefit of having ions stored against the concentration gradient as happens as a result of active transport?
they are a potential source of energy
What happens during secondary active transport?
solute moves down an electrochemical gradient, previously put there by primary active transport therefore releasing the potential energy
How is cotransport used during secondary active transport?
molecule is moved through the channel at the same time as the solute moves back down the potential gradient
How is counter transport used during secondary active transport?
two solutes move in opposite directions but use primary active transport to gain energy for the movement
How does secondary active transport use ATP?
indirectly sourced from primary active transport
