Talbot- Osmosis and Diffusion

Question 1

define diffusion ?

Answer 1

the movement of a solute suspended or dissolved in an aqueous solution down it’s concentration gradient due to random thermal movement .

Question 2

In diffusion the solute moves from ?

Answer 2

from high concentration to low concentration , no energy input require

Question 3

what is the physical factors /properties for diffusion ?

Answer 3

no energy input needed

efficient ( rapid) only over short distance

Question 4

what is the rate of diffusion (Jx) is proportion to ?

Answer 4

Proportional to the concentration gradient
inversely Prop. to distance L^2
( the greater the distance between 2 points the greater the time it take to diffuse .

Question 5

how we measure the rate of diffusion ?

Answer 5

as A FLUX RATE across the membrane

Question 6

how diffusion happened across the membrane ?

Answer 6

by simple diffusion , and Facilitated diffusion

Question 7

what is the difference between facilitated diffusion and simple ?

Answer 7

simple : solute moves from high concentration to low concentration .
Facilitated : solute moves from high concentration to low concentration DUE to specific transporters (protein Mediated )

Question 8

what is the flux rate?

Answer 8

how much of something moving over time .

Jx=dQx/dt ( change in quantity / change in time )

Question 9

what is the difference between influx, Efflux , net flux ?

Answer 9

Influx (Jin): movement of solute into a chamber /cell/compartment , 
Efflux (Jout) :  movement of a solute out 
net flux ( Jnet ) difference between (Jin)-(Jout)

Question 10

what is unidirectional flux ?

Answer 10

it is the net flux

Jnet =Jin - Jout

Question 11

All solutes and systems want to move towards what ?

Answer 11

Their own equilibrium , no matter what other solutes are present or what is their concentration are .

Question 12

does the living body moves towards equilibrium ?

Answer 12

NO , living body is an open system so it works to maintain a steady state .

Question 13

what is Fick’s equation ?

Answer 13

J= D A (dC/dX) 
(dC/dX)  concentration gradient 
A area 
J rate of diffusion ( moles /second)
D is diffusion coefficient or can be P ( when it is experimentally calculated)

Question 14

what is D proportion to ?

Answer 14

temperature , 1/viscosity ,

1/ molecule size of solute

Question 15

define Osmosis ?

Answer 15

diffusion of water , moving from low concentration of solute to high concentration of solute .

Question 16

how much water in our body ?

Answer 16

45%-70% of body mass

Men 60%, women 50%

Question 17

a man weight 70 Kg calculate the total body water TBW ?

Answer 17

men has 60% water so .60x70=42kg water

Question 18

what are the compartments of TBW total body water ?

Answer 18

all the water in the body ,
TBW =extra cellular fluid ( ECF) 34%
+ICF 66% Intracellular Fluid.

Question 19

what is ECF ? what are the compartments of it ?

Answer 19

Extracellular fluid : all fluid outside of cells

ECF= 25%vascular +75% ISF ( interstitial fluid )

Question 20

name the three body fluid compartments ?

Answer 20

Intracellular fluid
interstitial fluid
vascular fluid

Question 21

Define Osmolarity ? Molarity ?OSMOLALITY ?

Answer 21

Osmolarity : (osm/L) measure solute concentration , number of osmoles of solute particles per liter
Molarity : moles /liter
OSMOLALITY ? osm/Kg water , measure of the osmoles of solute per Kg of solvent

Question 22

Define Osmotic pressure (pi)? and what it is similar to ?

Answer 22

Pulling force that attract water towards more concentrated solution.
similar to hydrostatic pressure ( P=n/V)RT
Pi= (osmol/L) RT

Question 23

what is the osmolality of human fluids ?

Answer 23

290 mOsm

Question 24

water is at what osmotic level across most animal cell membrane ?

Answer 24

Osmotic equilibrium

Question 25

protein in plasma is more , less or equal to ISF ?

Answer 25

more in plasma

Question 26

what is predominant cation in ICF ?

Answer 26

K+ to balance proteinn - in ICF

Question 27

is there any ionic concentration different between all three compartments ( ICF, plasma , ISF) ?

Answer 27

yes , however they have effectively identical osmolarties.

Question 28

what is difference between Osmolarity and Tonicity ?

Answer 28

Osmolarity : is actual number of particles dissolved in solution represent a potential for water to move across a membrane. Tonicity : actual response of cells or tissues immersed in a solution , represent the FLUX OF WATER ACROSS A MEMBRANE

Question 29

what does that means when the cell is | ISO-osmotic, Isotonic environment ?

Answer 29

have no net flux of water because the intracellular and extracellular solutions are iso-osmotic

Question 30

what does that means when the cell is | Hypo-osmotic, Hypotonic environment ?

Answer 30

the environment is hyp-ismotic relative to the cell , cell is HYPER-osmotic relative to the environment, cell swell

Question 31

what does that means when the cell is | hyper-osmotic, hyper-tonic environment ?

Answer 31

the enviroment is hyper-osmotic to cell , and the cell is HYPO osmotic to the environment , cell shrink

Question 32

cell in its surrounding solution is iso-osmotic does has to be isotonic?

Answer 32

NO , it depends on the presence /absence of osmotically active solute

Question 33

what is osmotically active solute ?

Answer 33

the one that is impermeable or has limited permeability

Question 34

what solutions would be isotonic to ICF of RBC?why ?

Answer 34

145 mMNaCL, 290 sucrose , 95mM MgCl2, 289mM Na+ and 1mM proein they are Impermeable across the cell membrane , so the solution will be isotonic or isomotic.

Question 35

what solutions will permeable to the cell membrane ?

Answer 35

Urea, ethanol , and they will be hypotonic to the cell.

Question 36

the contribution of a solute to tonicity depend on what ?

Answer 36

its membrane permeability

Question 37

which part of the cell is sensitive to any small change in the number of the solute ?

Answer 37

IntraCELLULAR volume of the cell is small, it does not take much of a change in total number of solutes inside the cell to lead to changes in concentration and osmolarity.

Question 38

if substance stay on only a particular compartment what it is the volume ?

Answer 38

Volume ( L) = amount (g) / concentration ( mg/L)

Question 39

if portion of the substance is excreted or metabolized what is the volume ?

Answer 39

volume ( L) =( amount - excreted) / concentration

Question 40

how to measure Plasma volume ?

Answer 40

all the water in the blood , use albumin, or evans blue dye to bind to serum protein