Exam 10: Gene Isolation and Manipulation

When ligating pieces of DNA into a plasmid,a scientist will often transform the ligation products into competent bacteria to evaluate the success rate of the ligation (i.e.,the number of plasmids that now have extra DNA ligated into their sequence).Define one quick way scientists can assess the success rate of a ligation just by looking at the bacterial colonies.

You constructed a cDNA library in a lambda vector using mRNAs from a pea plant.You want to identify a rubisco (a protein involved in photosynthesis)clone among the 50,000 clones in the library.You have a rubisco cDNA from tobacco to use as a probe.When hybridizing the probe to the plaques in the library,would you use higher,lower,or the same temperature as for hybridizing the tobacco DNA to a tobacco rubisco clone? Why?

Detection of a transgenic plant can be accomplished in a number of different ways,but often the initially transformed cells (in tissue culture)are enriched for the presence of a transgene by:

Embryonic stem (ES)cells have the unique ability to:

What type of library would be most valuable in the isolation of promoter sequences found in front of a gene's transcriptional start site?

A circular DNA molecule has n target sites for restriction enzyme EcoRI.How many fragments will be produced after complete digestion?

In recombinant DNA technology,DNA is most often cut using:

A transgenic mouse is different from a knockout mouse in that:

A cDNA library is produced from ______________ and is valued in the analysis of __________________.

Which of the following sequences includes a clear eight base pair palindrome?

Identification of mRNA and initiation of priming for cDNA synthesis is accomplished by:

Foreign DNA can be introduced into a cell using which of the following method/s?

Gel electrophoresis can be used to separate DNA or RNA molecules based on their:

Homologous recombination in yeast facilitates the:

In a certain community,a mutant allele for Tay-Sachs disease is prevalent.This mutation removes a Hind III restriction site in the gene sequence.A probe is available for this region,with the following homology: Two couples in this community are expecting children.Each couple has a DNA test to determine if their child will have Tay-Sachs.The results of the Southern blot,probed for the region described above is shown below. \begin{array} {cccccc } \text { M1 } & \text { F1 } & \text { Child 1 } & \text { M2 } & \text { F2 } & \text { Child 2 } \\\end{array}\\ \begin{array} { | l l l l l l | } \hline \underline{\quad\quad} &\underline{\quad\quad} & \underline{\quad\quad} & \underline{\quad\quad}& \underline{\quad\quad} & \underline{\quad\quad}\\ \underline{\quad\quad}&\underline{\quad\quad} & & \underline{\quad\quad} & \underline{\quad\quad} & \underline{\quad\quad} \\ \hline \end{array} Using these results,how would you counsel the couples?