Genetics Lab Exam Flashcards
Lab 1: probability
Likelihood of a single event occurring
Product rule
Probability of 2 independent events being both occurring simultaneously is the product of their individual probabilities. “AND“
Sum rule
probability of either one or the other of two mutually exclusive events occurring is the sum of their separate probabilities. “OR”
Chi square
= total (obs - exp)^2 / exp
Likelihood that 2 sets of results are similar enough to consider them equivalent
Degrees of freedom
takes into consideration the number of independently varying Parameters.
Df= # classes - 1
Use DF for x^2
Chi square significant test results
If statistical test indicates that the difference between expected and observed results is significant then your null hypothesis (hypothesis of ‘no difference’) must be rejected.
X^2
greater the difference between the expected and observed values, the greater the X2 value and the lower the probability that this difference is due to random chance. It is generally accepted that a X2 value with a probability less than 0.05 (5%) indicates a low (<5%) probability that the observed values agree with the expected values by random chance. Therefore observed results are considered to be significantly different from expected results.
X^2 (chi square test) uses
Used to statistically determine whether the null hypothesis should be accepted or rejected
Pipettors
Used to transfer specific volumes of solutions quickly and accurately
Gel electrophoresis
Used to study DNA and it involves separating fragments of DNA for genetic analysis.
Is DNA positive or negative charge
Negative
What is the distance travelled through the electrophoresis gel indicate
- the size of the fragment (smaller fragments will travel further through the gel)
-charge
What is the gel in the electrophoresis made up of
Aragose, distilled water, ethidium bromide (EtBr)
What are restrictions enzymes
Proteins that cut DNA at specific sites. Each cut is made to the phosphodiester bond between specific nucleotides within the sequence. # of cuts depends on # of recognition sequences present in the original DNA molecule. Sequence is usually palindromic (sequence on both strands of the DNA is identical when read in the 5’ to 3’ direction.
Restrictions enzyme digest
Enzymatic manipulation of DNA. Cutting DNA at specific sites. Can be used to shuttle DNA from one organism to another.
One of the first restriction enzymes to be isolated
E.coli (EcoRI)
What types of ends can the cleavage of DNA from restriction enzymes create
Blunt ends or staggered ends
-cut made in middle of sequence usually leaves blunt ends
-cut anywhere else produces complimentary tails on the DNA fragments
Molecular marker or DNA ladder
A protein of a known band size that can be used to compare to your results in the lab to estimate their molecular size
What does assessing molecular weight and # of bands generated by each individual allow for (in a gel electrophoresis)
-identification of the restriction enzyme target sites within the DNA molecule
Restriction map
Map showing the relative locations of restriction sites.
-consists of long horizontal line (DNA molecule) and short vertical lines (cut locations)
How many bands are produced when there are 4 restriction enzyme cut sites
5 bands
In lab 3, what was used to extract DNA from a blood sample (or other biological materials)
Wizard kit
What must PCR reactions contain
Template DNA, free nucleotides, a forward and reverse primer set, and a DNA polymerase to build the new DNA molecules, buffer and magnesium chloride (provides optimal environment for process to occur)
If the DNA evidence matches the DNA from an individual, this evidence is considered to be what type of evidence
Inclusive evidence
-they MAY be guilty but need further evidence
(Forensics lab) If the DNA in the sample differs from an individuals DNA, what can we conclude (What type of evidence is this)
This individual can be ruled out as a suspect with certainty.
Exclusive evidence
Single nucleotide polymorphism (SNP)
Changes in certain DNA regions that only a very small portion of the population (5%) have to narrow down possible suspects
What do we use to amplify extracted DNA
Polymerase Chain reaction (PCR)
What does nucleic lysis do
Nucleic lysis solution breaks down cells and nuclei
What does proteinase K do
proteinase K enzyme breaks the bonds between the amino acids in the proteins.
At what temperature does proteinase K function at best when getting ready to run a PCR
55%
T/F: PCR is extremely sensitive to any amount of DNA
True
A single cell can contaminate the PCR
What type of fish was used in lab 4 (Hardy Weinberg lab)
Chinook salmon
Probability equation
times event A occurs / total # of events
If you see AND with probability question…
Multiply
If you see OR with probability question…
Add
Hypothesis of no effect
Null hypothesis
If null hypothesis if found to be false, then what kind of hypothesis is found to be true?
Alternative hypothesis
Why do we use loading dye in gel electrophoresis
-Adds density to samples (without it, samples are more likely to float out of well, pulls them down into well)
-adds colour so that we can see the solution in the well