1. Describe the process of diffusion in cells (not more than 2 pages).
2. Derive the equation for Fick's second law.
3. Draw a typical FRAP curve and explain its different regions.
4. Using Fick's law explain why the doubling times of rod-shaped bacteria are significantly shorter than those of spherical bacteria.
5. A protein with a density of 1.41 g/cm3 has a molecular weight of 5000 g/mol.
a. Calculate its radius.
b. The radius measured during an experiment turned out to be 2.24 X 10-7 cm. Is this different than the one calculated in part a? If yes, explain this discrepancy.
6. During an experiment, the osmotic pressure was recorded with respect to different concentrations of an enzyme. The results of the experiment are shown in the table below.
Osmotic Pressure(atm) Concentration of Enzyme (g/L)
0.0015 1
0.0044 3
0.0141 10
0.0387 30
0.1034 90
a. Calculate "apparent" molar weight at each value of osmotic pressure.
b. Plot the apparent molecular weights calculated 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, calculate 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 should his turbulence be attributed to and why.
9. Using appropriate mathematical identities, explain how it is possible to detect a calcified atherosclerotic plaque using a stethoscope.