Lab 1 Flashcards
What are the safety guidelines for lab 1?
Salmon sperm DNA and BSA are typically harmless to human body, but sill handle them with caution. Rinse with running water immediately and thoroughly if it gets on your skin.
Why do we use micropipettes for this lab?
One microliter is 1/1000 of 1 milliliter (mL, 1 mL = 1000 μL), which is a volume too small to be measured using a graduated cylinder. Micropipettes are used to handle these small volumes with high accuracy and relative ease
Why must micropipettes be used with a tip, specifically with the proper size?
Handling solutions without these tips will contaminate/damage the micropipette
Which pipette should you use when the volume required overlaps with two + types?
When pipetting volumes within this overlapping range, use the smallest micropipette which can handle the volume in one go
Should you adjust pipettes past their range? Why/why not?
No. Can cause damage.
Why should you release the plunger slowly?
Releasing the plunger too quickly results in inaccurate pipetting such as air bubbles getting introduced into the pipette tip.
Explain first and second stop when using micropipette.
Gently press the plunger to the first stop, which will dispense most of the solution. Then, press the plunger to the second stop to completely dispense the rest of the solution remaining in the tip.
How deep should the tip of the pipette be inserted into a solution?
Try to hold the end of the pipette tip close to the surface of the solution. Avoid inserting the tip deeply into solution as this may cause some of the solution to stick on the surface of the tip.
Should the largest or smallest volume be added to the tube first?
Largest
What is important to remember when pipetting different reagents?
Use a different tip for each reagent.
What is the relationship between Absorbance and optical density in this exerice?
absorbance at 260 nm = optical density at 260 nm = OD260).
What does The ratio of OD260 and OD280 provide a measure of?
Sample purity.
What OD ratios do pure DNA and RNA have?
1.8 and 2.0,
Why are we using a smaller aliquot?
Using smaller aliquots of reagents (in this case, water) to set up reactions reduces the numbers of times you open the larger storage container, lowering chance of contamination.
Why do different proteins absorb UV light at different rates?
Different proteins absorb UV light with different rates as each protein has different amino acid compositions.
