Pipetting
What pipette would you use to measure 11 µL?
P20
If you dilute 1 mL into 9 mL, what is the dilution factor?
1:10
What is the primary purpose of gel electrophoresis?
Separates DNA by size
DNA is measured at what wavelength?
260 nm
What happens to PCR if there are no primers?
Reaction won’t start
What pipette would you use for 675 µL?
P1000
After 3 1:10 dilutions, what is the final dilution factor?
1:1000
What factor primarily determines the rate of DNA migration?
Size of DNA fragments
Proteins are measured at what wavelength?
280 nm
What does Taq polymerase do in PCR?
Builds new DNA strands (heat-stable DNA polymerase)
What color tip is used for 75 µL?
Yellow Tip
A 1000 µg/mL stock is diluted 10^-2. What’s the new concentration?
10 µg/mL
What does DNA dye do?
Binds with DNA to visualize bands
Bacterial cell density is measured at what wavelength?
600 nm
Why is Taq polymerase better than regular DNA polymerase for PCR?
Taq can survive high heat during PCR cycles, unlike regular DNA polymerase, which denatures
What’s the first step in calibrating a micropipette if it gives inconsistent results?
Tare balance with water and weigh
If you do 4 serial dilutions of 1:10, what’s the total dilution factor?
1:10,000
What does loading dye do?
Adds color/weight to track sample in wells
Why do we use a standard curve in spectrophotometry?
To compare unknowns to known concentrations
Give one example of how a change in genotype can alter phenotype.
Mutation → altered protein → changed trait (e.g., colony morphology)
Why is calibration important in micropipetting?
Ensures accuracy and reproducibility in experiments
Why do scientists use serial dilutions instead of one large dilution?
More accurate and manageable steps
Agarose vs. Agar — which one is used for DNA gels, and which for bacterial growth?
Agarose = DNA electrophoresis, Agar = bacterial colonies
What feature shows a “good” standard curve?
Straight, linear line with best fit
What are three essential components (ingredients) needed for PCR, besides the DNA template?
Primers, nucleotides (dNTPs), and Taq polymerase