Transport Through Membranes Flashcards
Name the 3 body fluid compartments and what they’re seperated by
Plasma(blood)
Leaky epithelium (capillary) Barrier
Interstitial fluid
Plasma membrane barrier
Intracellular fluid
What molecules are let through the plasma into the interstitial space through pores in leaky epithelium
Small molecules such as ions
No large molecules like proteins or red blood cells
Which body fluid has no proteins in it
The interstitial fluid
Where are the most ions exchanged located
Extracellular fluid. Intracellular fluid has very low concentration of ions
What is the difference in ion composition between extracellular and intracellular called
Chemical disequilibrium
What 2 things cause chemical disequilibrium
There is active transport of NA out of the intracellular space (for active transport)
The plasma membrane is a barrier to ions passing due to them being polar
What moves freely in all 3 body fluids
Water , moves via osmosis across all 3 membranes
What is meant by solution solvent and solute
Solvent is water usually
Solute is eg glucose (makes something concentrated)
Solution is the mix
All compartments have 300 mOSM. This means they’re in a state of osmatic equilibrium. What is another word for this
Isosmotic
What is osmolarity
Number of the particles eg glucose per volume (L) of solution
How do you calculate osmolarity
Molar concentration x number of particles
Eg naCl = 2 particles
1M x 2 = 2 osm
How do you go from mOSM to osm
/ by 1000
What happens to osmolarity if there is increase in molecules/ions
The osm goes up (as conc goes up)
Where does water move
From low OSM (low conc) to high OSM (high conc)
What happens in terms of osmolarity when you drink water when you sweat (lose salt and water)
The ecf decreases in OSM (dilution of ions) this means water moves out of the ecf into the intracellular space which is bad
What events occur when you get extra intake or ions eg na Cl when eating
There is increase in ions in ECF. This will increase the OSM. This causes water to move out of the intracellular fluid
Causing signal to the thirst centre
The intracellular space has many organic solutes such as amino acids, proteins, sugars. What does this attract that contributes to its OSM
Counterions
This would increase the OSM (high concentration)
How does the icf counteract the high osm due to counterions and how is this dangerous
A lot of water is drawn in
This can be dangerous and cell could burst
What does the icf naturally large osm get solved by
Actively pumping Na+ out of cell (3) And K (2) into cell
This causes a chemical disequilibrium
Decreases the HIGH OSM
Explain the process of the na+ k pump
3 na will bind to the active site and 2 k will bind
Atp ase hydrolyses atp into adp. Causes conformational change. This causes movement of na out of cell and k into cell
What are transport proteins called that only transport 1 molecule
Uniporter
Eg GLUT 4
What does primary active transport mean
The process in which energy ADP is generated through hydrolysis and also a chemical disequilibrium
Via the k/na ATPase system
How does primary active transport allow secondary active transport
Secondary AT uses the gradient of ions produced by primary AT eg in co transport
What is the co transport protein called that moves 2 molecules into same direction (down conc gradient)
Symporter
What is the co transporter that transport 2 molecules in different directions called. And give example
Anti Porter
Eg calcium/na anti Porter
Calcium moves out and Na moves in
Give examples or 3 primary active transporters
Na/k ATPase (anti Port)
Ca2+ ATPase
H+ ATPase (proton pump)
