WorksheetsGenomics and cDNA Libraries
Total questions: 23
Worksheet time: 13mins
A gene library is
A collection of clones that represent the entire genome of an organism.
cDNA library is
A collection of complementary DNA fragments generated from mRNA that present in the originating cells.
Partial digests
Partial digests are a method used in DNA sequencing to create a collection of overlapping DNA fragments
Partial digests involve complete sequencing of non-overlapping DNA fragments
The number of independent clones that are needed can be calculated from the formula:
N=ln(1−f)ln(1−P)
N=ln(1−P)ln(1−f)
N=ln(1+f)ln(1+P)
N=ln(1−f)ln(2−P)
f= the fraction of genome represented by an average clone, which is calculated by
f = average insert size - total genome size
f = total genome size / average insert size
f = average insert size / total genome size
f = saverage insert size * total genome size
A gene library would normally be kept at
−90 oC
24 oC
−20 oC
−80 oC
Bacterial cells in a plasmid library are protected from the adverse effects of freezing by
Glycerol
Low temperature
Phage libraries are cryoprotected by
Adding dimethyl sulphoxide (DMSO)
Plasmid libraries in cells are simply spread out on agar plates containing the appropriate antibiotic, which ensures that the cells do not shed their plasmids.
True
False
Oh my brain
TT
Phage libraries first need to be mixed with, and infect, prepared viruses before being plated out.
True
False
Meow
Hybridization is based on the difference in stability between the _____, _____ that bind the two strands in the double helix together by base pairing.
covalent bonds, hydrogen bonds
van der Waals forces, hydrogen bonds
covalent bonds, van der Waals forces
ionic bonds, covalent bonds
Denaturation of DNA by
gentle heating or high pH
heat or high pH
freezing temperatures or low pH
Renaturation of DNA by
Increasing temperature or low pH
Heat or high pH
lowering temperature or pH
Lowering temperature or high pH
The separation of the strands during denaturation causes a radical change in the physical properties of DNA, such as ______, which changes dramatically over a short temperature range.
optical density
intensity
The strength of the association between two bases depends also on the adjacent bases, because :
Heteroduplex is
A DNA molecule with two strands that are mismatch
A fundamental feature of nucleic acid hybridization is that the probe is labelled in a way that will make it possible to detect it.
True
False
The classic way to detect radiolabelled probes is to place the probe-target hybrid on
X-ray film.
a probe coming from the same gene in the same species is called
If the gene we are trying to clone is not completely unknown, and a related one has already been cloned and characterized from another source, then we can use that clone as a :
heterologous probe.
heterozygous probe.
homologous probe.
Antiserum is
A mixture of antibodies that can react with several different part of protein
The most basic procedure to characterize the plasmid, and the fragment that it contains is to
look for a change in the size of the plasmid compared to the original vector.
run total DNA extracts or crude plasmid preparations on an agarose gel
Once you have found one that does produce the correct size of product in the PCR, you can determine the sequence of the PCR product to confirm the nature of the Insert by
DNA sequencing.
Protein sequencing
Gel electrophoresis
PCR
