What was the early technique used in molecular genetics to study "alleles" of various enzymes?

A student researcher performs indirect immunofluorescence of mammalian cells for a transmembrane protein with an antibody to the C-terminus of the protein. First, the student researcher does not permeabilize cells' plasma membranes and stains with the protein specific antibody. Secondly, the researcher permeabilizes the cells' plasma membranes and stains with the protein specific antibody.

What is the student researcher trying to determine with these two experiments?

Which of the following is not a valid method to introduce exogenous DNA into a cell?

Work on the Anopheles mosquito attempting to study the blood digestion process found that over 2,000 genes were upregulated and downregulated through digestion. What technology makes it possible to study expression levels of large number of genes like this?

Two students have cloned a bacterial DNA polymerase into a mammalian expression vector. The students then transfected the vector into human tissue culture cell lines to determine if the DNA polymerase retains its native function in human cells.

What technique is most suitable for the students to use to determine if the DNA polymerase is expressed in human cells?

Which of the following techniques most likely utilizes a detergent, such as sodium dodecyl sulfate?

Which of the following techniques would best determine relative protein activity by its ability to bind specific DNA sequences in vitro?

What is the purpose of adding sodium fluoride to a cell lysis buffer?

What technique allows scientists to measure gene expression via probe-cDNA hybridization fluorescent intensity?

What is the purpose of a phenol/chloroform extraction?