Online Labs
Your figure caption should appear _______ your figure
What is below?
Should you use a 2-20 uL or a 20-200 uL pipette to pipet out 20 uL of liquid?
You should use a 2-20 uL pipette since pipettes are more accurate in the middle to top of their range
What are the three steps in a cycle of PCR?
Denaturation, Annealing, Extension
If sample B travelled further than sample A after both samples were ran on a gel for 40 minutes, which sample has bigger fragments?
Sample A has bigger fragments since it travelled relatively less distance than B.
What are two methods for balancing a centrifuge when there are three sample test tubes that need to be ran?
One method is adding a blank sample in a square shape, and the triangular shape with the three full samples.
If I copy and paste an entire paragraph but change five to seven words, this is not considered plagiarism. True or false?
What is false?
How would you arrange two centrifuge tubes in a microcentrifuge?
Directly across from each other so the microcentrifuge is balanced.
Why is it important to use sterile water in PCR?
To avoid other potentially contaminant DNA or RNA from being in your sample
Why is a DNA ladder used in gel electrophoresis?
To have a basis for comparison of your DNA samples
A DNA strand with more GC content needs a ______ denaturation temperature in PCR.
Higher. Guanine and cytosine are connected with 3 hydrogen bonds. More bonds to break, the higher temperature needed to break the DNA apart
In-text citations are required in cases where you incorporate an idea or a result from someone else in your paper. True or false?
What is True?
What are two important reasons for secure attachment of a lid in a centrifuge?
Reducing noise and aerosols. An unsecure lid could fly off and damage the machine and the samples.
List three components of a PCR sample before it enters the thermocycler
Any three of Taq polymerase, dNTPs, DNA, primers, and cofactors.
What do bubbles at the gel electrodes indicate?
They indicate that a current is running, allowing DNA to travel through the gel.
When something is precipitated out of solution, the solid part is the pellet, whereas the liquid part is called:
What is the supernatant?
What’s wrong with the following paraphrase of a scientific paper? According to her paper from 2016, the cheetah is the fastest land animal.
Who is the author?
What were the roles of isopropanol and ethanol in the last steps of extraction?
Isopropanol precipitates out the DNA so that it can be isolated. Ethanol is a washing step to remove impurities.
In which step of PCR is temperature set highest, and why? What is this temperature?
The denaturation step, to separate the dsDNA into single strands. This temperature is roughly 94 degrees Celsius.
Is DNA moving towards the positive or negative electrode, and why?
DNA, as negatively-charged molecule, is moving towards the positive electrode, as opposite charges attract
This is added to ensure that your DNA sample sinks into the well
What is the Loading dye?
All figures presented should be discussed in the paragraph right before the figure. True or false?
What is true?
Describe post-rinsing technique. When would you use it?
Post-rinsing technique is used when pipetting 20 uL or less. In this technique, you expel the small amount of liquid you have directly into the water/buffer and depress to the first stop and release several times, before depressing to the second stop and pulling the pipette up.
Describe the importance of forward and reverse primers. What would happen if you only had the forward primer while running PCR?
Forward and reverse primers ensure that DNA replication occurs on both strands. If only the forward primer was present, then only one of the strands would replicate!
List two reasons why you may have not had a band appear in your gel.
SYBR Safe was not added (which stains the DNA so it can be seen)
DNA degraded by the time you ran your experiment
Your bands ran off the gel by running it too long
This lab exam is worth how much of your entire course grade
What is 15% 😩