Answers to questions 1-11 of this exam are to be completed and e-mailed to Dr.
Rinehart's by 3:30 PM Monday October 2. Printed answers to questions 12 and 13 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! You may inquire about general
principles from instructors that have presented material to you but you may not ask them
to answer these questions directly! 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 that can be addressed with
immunological techniques. (20 points)
- How would you prepare 1 liter of the following sterile culture media? (20 points)
- 1% Yeast Extract
- 1.5% BactoTryptone
- 0.5% NaCl
- 10 mM NaOH
- 50 µg/mL Ampicillin
Note that ampicillin is not stable above 45 degrees C. You are given a non-sterile
stock of 25 mg/mL ampicillin and 10 N NaOH. All other components are available as dry
stocks. The final solution should be completely sterile!
- What are four factors that can cause errors in preparation of a buffer with a specific
pH? (3 points each)
- A small south-sea-marine animal is known for it's brilliant colors. Local legend has it
that the silver and gold markings are more than just colors but are actual accumulations
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!)
- Describe how you might determine the specific location of a small, membrane associated
protein inside a eukaryotic cell.
- Given the following components:
- Trizma base, MW = 121.1
- MgCl2, 10 % (w/v) stock solution
- 2-Mercaptoethanol, 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) 2-Mercaptoethanol; 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 and their pH adjustment should be done together. 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 pH of 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. Graph the pH of titration to final
concentrations of HA = 0.00001 M and A- = 0.1 M. (You may want to represent the
concentrations as log values or set this axis to a log scale.) Title the graph
"Titration" and label the x-axis as "[A-]" and the y-axis as pH.
