Answers to questions 1-10 of this exam are to be completed and e-mailed to Dr.
Rinehart's by 3:30 PM Monday October 10. Printed answers to questions 11 and 12 should be
placed in Dr. Rinehart's mailbox (room 201 TCNW) by the same time. You may consult your
book or notes but DO NOT ask for help from you peers or professors! This exam is to
be done on your own.
Just because you have over 1 week, do not wait until the last minute to do this
assignment. Most of these questions will require some thought.
Matching (2 points each)
- a. Darkfield Microscopy
- b. Phase Contrast Microscopy
- c. Interference Microscopy
- d. Polarization Microscopy
- e. Differential Interference
- Contrast Microscopy
- f. Fluorescence Microscopy
- g. Brightfield Microscopy
- _____ Can be used to determine the thickness of an object if the refractive index is
known.
- _____ Can be used to locate viral DNA inclusion bodies inside a cell.
- _____ Can be used to view helical arrays as are found in Tobacco Mosaic Virus.
- _____ Can be used to visualize stained tissue.
- _____ Used to count objects where not much detail is needed.
- _____ Good method to visualize membranes and organelles
Short Answer and Problems
- List and/or briefly describe 6 biological problems/assays that can be addressed with
either absorption or fluorescence spectroscopy. (20 points)
- What are four factors that can cause errors in preparation of a buffer with a specific
pH? (3 points each)
- You have just purified a DNA binding protein and want to know if it contains zinc, which
would be indicative of the presence of zinc fingers. How would you determine if zinc was
present?
- A small marine animal is known for it's brilliant colors. Legend has it that the silver
and gold markings are more than just colors but the actual accumulation of these precious
metals. How would you go about either proving or disproving this legend? (Remember the
historical consequences of being the bearer of bad news among some cultures!)
- Given the following components:
- Trizma base MW = 121.1
- MgCl2 10 % (w/v) stock solution
- ß-ME 100% (v/v) stock solution
- NaHCO3 MW = 84
- RuBP MW = 438.5 make a 2 mM stock solution
Propose a protocol for making 0.2 mls of the following reaction buffer: 150 mM
Tris-Cl, pH 8.2; 0.2 % (w/v) MgCl2; 0.2% (v/v) ß-ME; 25 mM NaHCO3; 0.4 mM RuBP.
(NOTE: You can not accurately weigh out less than 1 mg of a dry chemical nor measure
less than 1 µL of solution. You cannot measure the pH of a solution with a volume less
than 5 mls. If your proposed solution preparation scheme requires doing any of the above
tasks you will need to re-think your procedure. Both Trizma and NaHCO3 will contribute to
the buffering of the solution. You may want to make these up as concentrated stocks since
they are relatively cheap, hint. Don't forget the pH! Also note that RuBP is $846/mg (MW =
438.5). (20 points)
- Complete the following spreadsheet assignment. (20 points) Graph the titration of a
buffer HA -> A- + H+, where the pKa is equal to 6 and the initial concentration of HA
is 0.1 M and the concentration of A- is 0.00001 M. Title the graph "Titration"
and label the x-axis as "[A-]" and the y-axis as pH.
