Lecture 5 - PHYS - Body Fluids

Question 1

what is diffusion

Answer 1

Diffusion is the process by which molecules will distribute themselves throughout a solution until there is an equal concentration throughout

Question 2

what is facilitated diffusion

Answer 2

protein channel creates a pore in the membrane that allows passage (with conc. gradient)

Question 3

what is active transport

Answer 3

contents actively pumped across the membrane in a process that consumes energy (goes against conc.gradient)

Question 4

5 factors which influence speed of diffusion

Answer 4

1. temp
2. conc
3. molecular weight
4. membrane permeability (number of channels)
5. surface area

Question 5

exterior of cells contain which ions

Answer 5

• sodium
• chloride

Question 6

interior of cells contain which ions

Answer 6

• phosphates
• potassium

Question 7

water flows from…

Answer 7

low to high solute conc

Question 8

define osmotic pressure

Answer 8

minimum pressure which needs to be applied to a solution to prevent the inward flow of its pure solvent across a semipermeable membrane

Question 9

is plasma membrane permeable to water

Answer 9

no, needs special proteins

Question 10

aquaporin channels

Answer 10

proteins which allow water flow (passive)

Question 11

osmolarity

Answer 11

measure of solute concentration (Osm/L)
glucose = 1 Osm/L
NaCl = 2 Osm/L

Question 12

tonicity

Answer 12

relative concentrations of dissolved solutes on either side of a semipermeable membrane. (eg hypertonic)