Answer the following problems
1. Expalin the process of diffusion in cells
2. Derive the equation for Fick’s second law.
3. Draw the typical FRAP curve and describe its different regions.
4. Using Fick’s law describe why doubling times of rod-shaped bacteria are significantly shorter than those of spherical bacteria.
5. A protein with the density of 1.41 g/cm3 has the molecular weight of 5000 g/mol.
a. Compute its radius.
b. Radius measured during the experiment turned out to be 2.24 X 10-7 cm. Is this different than the one find outd in part a? If yes, describe this discrepancy.
6. During the experiment, the osmotic pressure was recorded with respect to different concentrations of an enzyme. The results of experiment are shown in the table below.
Osmotic Pressure Concentration of
(atm) Enzyme (g/L)
0.0015 1
0.0044 3
0.0141 10
0.0387 30
0.1034 90
a. Compute “apparent” molar weight at each value of osmotic pressure.
b. Plot apparent molecular weights computed in part a, against respective concentration values and find the best estimate of enzyme’s molar weight.
7. A protein was observed to move 300 μm in 12.7 minutes at 23 0C. Assuming its density and viscosity to be 1.34 g/cm3 and 0.89 X 10-2 g/cm s respectively, compute the following parameters related to the
protein’s shape and its movement.
a. Diffusion coefficient
b. Friction coefficient
c. Radius
d. Volume
e. Molar weight
8. Turbulent blood flow in anaemic patients is not uncommon. What blood flow parameters must this turbulence be attributed to and why.
9. Using suitable mathematical identities, describe how it is possible to detect a calcified atherosclerotic plaque using a stethoscope.