Cell Volume

Question 1

Three properties for movement across membrane

Answer 1

Permeability, Concentration gradient, Electrical potential

Question 2

3 ways to keep cell from bursting

Answer 2

Impermeable Cell
Rigid Cell Wall
Osmotic Dilution

Question 3

Osmosis vs Diffusion?

Answer 3

Diffusion is movement down concentration gradient. Osmosis is movement of water.

Question 4

What substances can cause volume change?

Answer 4

Only water! Relative concentrations of every other solute is negligible from a volume standpoint.

Question 5

Reflection coefficients

Answer 5

0 is water, 1 is impermeable
Solutes with lower coefficients diffuse faster, this can cause short term changes in osmotic movement where a cell would initially swell if loaded with high coefficient solute but would later shrink to normal as it diffuses out.

Question 6

Molarity

Answer 6

The number of moles of a single solute per liter

Question 7

Osmolarity

Answer 7

The total number of moles per liter of solution

Question 8

Equivalents

Answer 8

The amount of substance multiplied by its valence (think 1mol NaCl = 1 equiv Na and 1 equiv Cl; 1M Ca = 2 equiv)

Question 9

Tonicity

Answer 9

Measure of effective osmotic pressure gradient. Think of the “actual” movement of water after looking at concentration gradient and permeability.
Osmolarity is relative concentrations before permeability, concentration gradients, etc.