Lab - Week 1 Content - Membrane Transport Flashcards
What does the plasma membrane of most cells separate?
Intracellular and extracellular compartments
T/F: the plasma membrane does permit the movement of certain substances between the ICF and ECF
True
Have you revised membrane transport from week 1?
Yes
Osmosis is the term given to the movement of any ___________ across a __________________________
Solvent
Selectively permeable barrier
What kind of solutions are the ICF and ECF?
Aqueous solutions
For our purposes what does osmosis refer to?
The movement of water across the plasma membrane
What are a good model system in which to study osmosis?
Why?
Erythrocytes
Their plasma membrane is permeable to water but fairly impermeable to salts
If erythrocytes are placed in a hypotonic solution then water will flow…?
What will happen if the process continues?
What is the name of the resulting process?
Into the cell, DOWN it’s concentration gradient and the cell will increase in volume.
The cell will eventually burst, expelling the haemoglobin into the surrounding fluid
Haemolysis
If erythrocytes are placed in a hypertonic solution water will move…?
What will happen if the process continues?
What is the name of the resulting process?
Out of the cell
This will cause the cell to shrink
Process known as CRENATION
If erythrocytes are placed in a hypertonic solution water will move…?
What will happen if the process continues?
What is the name of the resulting process?
Out of the cell
This will cause the cell to shrink
Process known as CRENATION
What is the goal of the lab?
What kind of blood did we use?
To determine which aqeuous solutions are which
Sheeps blood
What is the rough osmolarity of sheep erythrocyte ICF?
Roughly 300 mOsm/L
How much of a drop of blood can we place on a slide with how much of the unknown, diluting solution?
1/10 of a drop of sheeps blood
1 drop of unknown solution
It is very important that only a very small volume of blood is applied to the slide so that you can observe…?
Why?
How long do you have to examine the cells within?
The shape of the cells
If when you look down the microscope and see clumps of cells your results will be meaningless
1-2 minutes of applying the solution in order to observe the changes (crenation or haemolysis etc)
If red blood cells are suspended in a solution containing a foreign substance to which the membrane is readily permeable, then this substance will…?
How long will this continue?
Rapidly diffuse into the cells down it’s concentration gradient.
This diffusion will continue until its concentration inside the cells is the same as its concentration outside the cells.