17 Questions
What mutation removes both restriction and methylation from the host?
hsdSB(rB- mB-)
Which mutation specifically eliminates restriction at the sequence C mCGG?
mcrA183
What type of plasmid is the F plasmid in E.coli?
Episome
What is the size of the F (fertility) plasmid in E.coli approximately?
100 kb
What is the function of the F plasmid in E.coli?
Codes a series of proteins for conjugative DNA transfer
What is the purpose of placing the T7 gene1 under the control of the lac promotor in the prophage?
To control the expression of the T7 gene1
What role does the lac operon play in the SHuffle T7 Express strain?
Regulates protein expression
Which strain is used for plasmid propagation with B/W selection and contains the following markers: hsdR514, supE44, supF58, lacY1, galK2, galT22, metB1, trp55?
DH5α
What is the best solvent to use for quantitating nucleic acid by absorbance of light?
Water
Why is the absorbance of light at 260nm used for quantitating nucleic acid?
It corresponds to absorbance by heterocyclic rings in DNA and RNA
What is the main concern when quantitating nucleic acid at 280nm?
Interference from other compounds
What does the genotype of a bacterial strain typically describe?
It tells you what the host can or cannot do.
What is the significance of the notation 'galK2' in a bacterial genotype?
It indicates that the second mutation characterized in the galK gene, which is part of the gal operon involved in galactose usage.
What is the purpose of quantitating DNA in molecular biology?
To determine the amount or concentration of DNA in a sample.
What is the role of restriction enzymes in molecular biology?
They are used to cut DNA at specific sequences, facilitating DNA manipulation and analysis.
How is the purity of DNA typically assessed?
Through the separation and visualization of DNA, often using techniques like agarose gel electrophoresis.
What is the purpose of using bacterial strains like DH5α and SHuffle T7 Express in molecular biology?
They are used as hosts for protein expression and plasmid propagation.
Test your knowledge on bacterial genotypes, gene expression, and the use of different strains for plasmid propagation and protein expression. This quiz covers topics like prophages, lac operon, and selection markers in bacterial strains.
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