You are preparing a sample of DNA from an unknown colony of bacteria.
After adding digestion buffer and incubating for the time suggested by the manufacturer, you centrifuge the sample.
The DNA is found:
a) stuck to the gel in the tube.
b) stuck to the sides of the tube.
c) in the pellet in the bottom of the tube.
d) in the supernatant in the tube.
Which of the following is not true of the Polymerase Chain Reaction?
a) PCR is facilitated by a heat labile DNA polymerase.
b) PCR is a method of replicating DNA in a test tube.
c) PCR can facilitate the detection of DNA that is too low to detect by other methods.
Why are dATP, dCTP, dTTP and dGTP added to a PCR reaction tube?
a) They catalyze the polymerase.
b) They buffer the mixture.
c) They allow the DNA in the sample to anneal.
d) They provide the building blocks of DNA.
Why are universal 16S rDNA primers used in your experiment?
a) They will anneal to highly conserved areas of the gene that encodes bacterial 16S rRNA.
b) They will anneal to unique sequences of genes encoding 16S rRNA in specific bacteria.
If universal primers are used to amplify DNA in a PCR reaction, then the PCR product must be sequenced to determine the bacteria that the DNA belongs to.
How is the PCR product separated from the PCR mixture at the completion of the reaction?
a) Perform electrophoresis in an agarose gel, stain the gel and cut the band corresponding to the PCR product from the gel.
b) Pour the PCR mixture into a commercially prepared DNA microconcentrator column and follow the manufacturer’s directions to adhere and elute the PCR product from the column.
c) Both of the above procedures may be used.
d) Neither of the above procedures may be used.
Your PCR product was sequenced by a method known as Cycle Sequencing.
Which of the following statements is false?
a) An automatic sequencer performs electrophoresis and reads the tagged DNA pieces, providing a read out of the nucleotide bases comprising the DNA sequence of the fragment being tested
b) Cycle sequencing is done in a PCR machine.
c)Tagged terminator nucleotides facilitate the creation of a series of nested DNA sequences of different length.
d) Cycle sequencing can be completed in just one test tube.
The National Library of Medicine has a databank called GenBank that has deposited in it the DNA sequences of numerous genes isolated from known bacterial species.
You obtained the following BLAST data from your sample:
99.9% Enterobacter sakazakii
95.2% Enterobacter aerogenes
93.7% Enterobacter cloacae
The pathogen in your sample is: