Membrane transport mechanisms

Question 1

Define Osmosis

Answer 1

movement of solvent from a region of high concentration to a region of low concentration across a semi permeable membrane.

Question 2

What is osmotic pressure?

Answer 2

water moving from a region of high concentration to a region of low concentration creates a higher pressure in one region. The increase in pressure is osmotic pressure

Question 3

Osmotic pressure formula

Answer 3

pi=g.C.R.T

Question 4

mechanisms used by substances to cross membranes

Answer 4

they can be
Energy independent
Energy dependent

Question 5

Energy independent mechanisms

Answer 5

types of transport: diffusion, facilitated diffusion, osmosis
require channels which can be
non gated: aquaporins & ions channels
gated: ligand gated & voltage gated

Question 6

Energy dependent

Answer 6

Type of transport: active which can be
primary- requires ATPases directly
secondary-requires multiporters (symporters & antiporters)

Question 7

Factors affecting rate of diffusion

Answer 7

diffusion depends on kinetic energy, its rate is affected by:
concentration differences across the membrane
membrane electric potential
pressure difference

Question 8

Factors that increase permeability

Answer 8

oil/water partition coefficient
size of solute
membrane thickness

Question 9

Equation for measuring diffusion

Answer 9

J= PA(C1-C2)
J=flow
P=permeability
A=area
C1 & C2=concentrations in compartments

Question 10

Differences between diffusion & facilitated diffusion

Answer 10

Diffusion only transport that is not carrier mediated
Facilitated diffusion requires uniporter carriers proteins that are gated (voltage & ligand gated) non gated( aquaporins, potassium & sodium channels)
diffusion and facilitated diffusion will have the same rate but different carrier transporter.

Question 11

Define diffusion

Answer 11

Random motion of particles

Movement of particles from a region of high concentration to a region of low concentration