Forces Across The Membrane 3

Question 1

Define osmosis

Answer 1

Net movement of H2O from regions of high H2O concentration to regions of low H2O concentration

Question 2

Define diffusion

Answer 2

Net movement of solute from regions of high solute concentration to regions of low solute concentration (same for osmosis but replace H2O with solute)

Question 3

Why is the body in osmotic equilibrium and what does this mean?

Answer 3

Why - Water can pass freely through between cells and the ECF.
Means - same conc (not volume) of water inside and outside cells
Not the same for solutes - not all solutes move across membrane freely.

Question 4

Describe H2O movements in the body

Answer 4

Passive (via aquaporins, protein water channels)

Question 5

What is H2O concentration inversely related to?

Answer 5

The concentration of solute - the more solute particles there are in solution, the more they will displace H2O molecules lowering the concentration of H2O.

Question 6

What happens if a solution of different concentration is separated by a membrane permeable to H2O and solute?

Answer 6

After time it will end up with equal concentration and equal volume either side of membrane - DIFFUSION.
solute molecules moving from compartments 1 to 2 and water from 2 to 1 - has to happen or volume wouldn’t be the same because if the solute was all that’s moving, compartment 2 would expand, but it doesn’t it says the same - happens until both same conc. (box diagrams and graph)

Question 7

What happens if a solution of different concentration is separated by a membrane permeable to H2O only?

Answer 7

It will end up with equal concentration either side of membrane but different volumes (assumes compartments are expandable)
Water moves until conc of water is same both sides but as solute cant move have to move more water to dilute down the more concentrated side so vol of compartment B will expand.