Variant 2B- osmotic pressure on erythrocytes Flashcards
Questions concerning influence of osmotic pressure on the volume of erythrocytes
1. The aim of the study (5)
To determine the dependence between volume and osmotic pressure of the
suspending medium
* from the obtained relation to estimate the apparent osmotically inert volume (Vn) ( u baso just extend the line to the y axis)
Give the definition of osmotic pressure, write the Van Hoff’s formula for the osmotic
pressure of an ideal solution. Explain the parameters involved (7)
Osmotic pressure is the minimum pressure which needs to be applied to a solution toprevent inward flow of its pure solvent across a semipermeable membrane
Pi=m/MV RT = iCRT
i is vant hoff coefficent
Describe shortly the experimental work and measurements performed in this practice (8)
osmotic prssure erythrocytes
- 5 testtubes of equal volume of erthroscyte suspension but , 2 hypotonic, 1 isotonic, 2 hypertonic
- put in vortex for 5 mins
- incubarion for 30 min
- then dertermine hemocrit
- centrifuge for 5 min at 1200rpm
- To find v realtive, divide each of the HCT values by the HCT isotonic
How will the volume of erythrocyte change if they are suspended in a hypotonic solution?
Explain why? (5)
The volume would increase due to the lower osmotic pressure
Water will move into the the erythrocytes and cause cell lysis
Which method for measurement of the products of free radical processes have you used for
determination of the antioxidative activity of chlorazine (7)
Induction of free radical oxidation of egg yolk lipoproteins in Chlorazin and look at
products with the TBA reaction and then calculate the antioxidant activity of a
substance by determining the absorbance.
Describe the model system and conditions for the occurrence of diffusion potential (7)
- Membrane is fully permeable for all ions
- In the system a concentration gradient exists (ions from high conc. Move to lower
conc.) - The ions have different mobilities (u->u+
Write the equation for the solute flux(Js) through a membrane transported by diffusion.
Explain the parameters involved (7)
d= dm/ Sdt
S= area
dm= mass of solute
dt change in time
Plot the dependence of concentration changes (lgC1/C) of Cl- with the time of dialysis in the
artificial kidney (t) (5)
decending graph plot time nd log
In the above graph draw the appropriate line and determine the halftime (t0.5) having in
mind that Ig from 0.5 is equal to minus 0.301 (5)
log 0.5= -0.3 so just follow up to the correspoding time on graph
Represent schematically the time course of the diffusion potential in a model system.
Describe the different sections in the curve and the processes characterizing them (7)
also hendersons?
Trapezium looking graph
- Write the equation for the permeability coefficient through a membrane for a substance
moving freely through it. Explain the parameters involved in the equation (6)
P= KD^m/l
Describe shortly the experimental work and measurements performed in this practice. Show
on a graph how the halftime of the concentration decay (8)
artificail membrane practical
- fill flask soltuion of Nacl
- goes thprugh peristatic pump
- on the other side, water is pumped whioch goes to waste flask
- So one side of the membrane is 0
*We take 2ml from the dialysed solution every 5 mins
* Follow up of the concentration decay lasts about 30 mins
* Represent the plot over time
Represent a sketch of lipid monolayer in the state of maximal molecular packing (6)
Plot the dependence of deformation of the skin on the applied hydrostatic pressure
difference TriP (5)
linear graph
The deformation of the skin is directly proportional to the applied hydrostatic
pressure
* As the hydrostatic pressure increases the deformation of the skin also increases
* There is a linear relationship for the data provided
* The deformation is still inside the point of reversible deformation
* Only the elastic property is tested for this set of data, the viscose property is tested
outside the limit of proportionality
