6) Passive Transport Of Neutal Particles

Question 1

Passive transport

Answer 1

Uses energy stored in gradients of
Concentration
Osmotic pressure
Hydrostatic pressure

To move molecules, ions or atoms in a particular direction

Question 2

Flux density

Answer 2

This is a measure of transport

J=dm/ds.dt

J is flux density

Question 3

Ficks first diffusion

Answer 3

This is simple diffusion the net transport of solute molecules through a solution

J=-D dc/dx

Question 4

Diffusion constant

Answer 4

For biological molecules it’s usually in the range of 10^-11 to 10^-10

D=kTu

K is Boltzmann constant
T is temperature
U is particle mobility

Question 5

Diffusion constant and molecular mass

Answer 5

The mass of spherical molecule is proportional to r^3

M ~ r^3

D~1/cube root of M

Question 6

Ficks second law

Answer 6

Describes the concentration of the diffusing substance in time and space

T =x^2 /2D

Question 7

Diffusion across membrane

Answer 7

Is much slower than simple diffusion

Flux density: is proportional to conc of difference

P=D/d
Permeability
d is membrane thickness

Question 8

Diffusion of lipophilic substances

Answer 8

P = lander D/d

Question 9

Diffusion through pores

Answer 9

P = npir^2 D/d

N is conc of pores
R is radius of pores

Question 10

Facilitated diffusion

Answer 10

Passive transport via a transport protein or carrier

Inhibitors bind to transporter, not transported, structure is similar to molecule being transported

Flux density
J = c/c +km j0

Question 11

Osmosis

Answer 11

This is the diffusion of s solvent across a membrane

Water molecules travel from places of low water potential to areas with high water potential

Question 12

Isotonic

Answer 12

Isotonic is when solutions have equal osmotic pressure

Hypertonic is when soloution has higher osmotic pressure

Hypotonic is when solution has lower osmotic pressure

Question 13

Animal cells in isotonic, hyper and hypo

Answer 13

Isotonic- no change
Water leaves the cell the cell changes shape and shrivels and then water re enters

Hypertonic- water leaves the cell bc there is low water potential outside of the cell

Hypotonic - water enters the cell and become turgid with water

Question 14

Filtration

Answer 14

Passive transport of solvent across a membrane due to hydrostatic pressure gradient

Question 15

Conjugate process

Answer 15

If the membrane is permeable to both solute and solvent

The water flux changes the conc gradient and influences the solute flux

Question 16

Electroosmosis

Answer 16

External electric field moves charged particles

Electroosmosis is when the water flux is ionic flux

Question 17

Steaming potential

Answer 17

Filtration of electrolyte through membrane results in a potential difference across the membrane

Reverse of electroosmosis

Question 18

Water transport in tissues

Answer 18

In the blood capillaries and glomerulus of kidneys hydrostatic pressure has the most effect

Usually osmosis and electroosmosis are used for transport of substances across the membrane