Week Three – "Laboratory Math"

The only place where success comes before work is in the dictionary.
Vidal Sassoon

Monday holiday

Holidays are usually welcome, but they pose a problem when we have only one opportunity to present background material each week. Perhaps with the time off you can peruse the background information on interpreting the findings from last week. Please have questions ready so that we can help you during lab or during office hours.

On your own – before your laboratory session

• Write up the materials and methods and results sections for your first research paper, due at the beginning of lab
• Before your lab day review "Laboratory Math," which presents the work to be done this week; links to relevant background topics are included in the write-up; you should come in with the following knowledge and capabilities:
• Be able to describe the differences among suspensions, solutions, and colloids
• Be prepared to write appropriate units for volume, amount, and concentration
• Be able to explain what is meant by w/w, w/v, v/v, and molarity
• Be able to describe the general principle behind a colorimetric assay
• Be able to describe two situations in which the formula c₁v₁=c₂v₂ would be used
• Complete Pre-Lab #2 no later than midnight before your lab day, print your answers, and bring a copy to the laboratory

Pre-laboratory orientation

• Review of safe laboratory practices
• Brief orientation to using balances, glassware, and similar apparatus
• How to use an automatic pipettor
• How to calibrate and use a Spectronic 20 spectrophotometer

Laboratory work this week

You will prepare a set of protein assay standards, add color reagent, calibrate a spectrophotometer, and use the instrument to read absorbances. You will prepare two unknowns for assay and read their absorbances. You will prepare a protein standard curve in your notebook and use it along with additional information to obtain concentrations for you unknowns and fraction yields. Finally, we will give you some dilutions to perform in lab if there is time, or to plan as a homework exercise if there is not enough time. You will troubleshoot common protein assay errors and determine the accuracy and precision of your automatic pipettors.

Follow-up work

• Start on your preparation for the fourth week of the course (Week 4 schedule page)
• Complete and submit Pre-lab #3 no later than midnight before your lab day
• You must enter your link (given to you in the Monday lecture this week) in the "Text Entry" stage of CPR no later than midnight Friday 11 Sep
• Calibration and reviews for CPR for the first assignment will "go active" on Saturday 12 Sep
• Plan to complete the calibration, peer review, and self review for the first results section by midnight Saturday 19 Sep; CPR will close precisely at midnight
• Begin working on the discussion, abstract, and introduction sections for your first research paper, due week 5