Diffusion and Osmosis (Passive Transport) Flashcards
What is oedema?
Swelling of tissue, too much water.
What molecules can freely pass through the membrane? What can’t? Give examples of unusual ones.
Hydrophobic and small ones can - gases such as O2 and CO2 as they’re small and hydrophobic, water and ethanol as they’re small, even though they’re hydrophilic
Charged, large and hydrophilic can’t eg. glucose, ions and proteins
Why can’t charged particles easily cross the membrane?
They have a charge so they’re polar and attracted to water, meaning they’ll be repelled by the non-polar hydrophobic core of the membrane.
Three types of passive transport
Simple diffusion
facilitated diffusion (channels and carriers)
osmosis
Types of active transport
Primary
secondary
vesicular (vendo and exocytosis)
Factors affecting diffusion rate
size of the concentration gradient
surface area of the membrane
size of the molecules (smaller ones = faster diffusion)
distance a molecule has to travel
liquid solubility of the molecule aka. hydrophilic/phobic when it comes to the cell membrane
Define osmosis
A type of diffusion across the semipermeable membrane which involves the movement of water from a high water/low solute concentration to a low water/high solute concentration
What is osmolarity and what is it measured in in biology (cell level)? Osmolarity of most bodily fluids?
The measure of solute concentration / number of particles per litre of solution. Measured in milliosmoles per litre (mOsm/L)
300 mOsm/L
How much fluid (ratio wise) is in our ICF and our ECF?
ICF 2/3
ECF 1/3
What is tonicity?
The ability of a solution to change the shape of a cell by changing its internal water volume via osmosis. Dependant on the concentration of non-permeable solutions on either side of the membrane.
