Lab Techniques: Electrophoresis And Blots

This is an MCQ-based quiz for GRE on the topic of Electrophoresis And Blots.

An electrophoretic system consists of two electrodes of opposite charge (anode, cathode), connected by a conducting medium called an electrolyte. There are three types of blotting methods: Southern blotting, Northern blotting, and Western blotting.

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When performing a western blot, what is the purpose of adding a secondary antibody?

Allow for detection of the protein sample Block any interfering noise coming from the membrane Ensure that the primary antibody binds properly to the sample Separate the sample from other proteins

A student researcher overexpresses an exogenous protein in cell culture and wants to determine if that protein, is in fact, overexpressed. What technique would best demonstrate that this protein is expressed in these cells?

Southern blot Electrophoretic mobility shift assay (EMSA) Northern blot None of the other answers Western blot

After proteins are run on an SDS-PAGE gel, a transfer is executed. What is the purpose of the transfer in Western blot protocol?

Move proteins from the SDS-PAGE gel to a nitrocellulose membrane None of the other anwers Visualize the proteins run on the gel Probe the gel with an antibody to detect a protein of interest Denature the proteins in the sample

Which of the following is not a similarity between enzyme-linked immunosorbent assays (ELISAs) and western blots, two common protein detection methods?

Detection of protein using antibodies specifically generated against antigens Tissue sample must be homogenized and the protein extracted to utilize the assay Requirement of antibodies conjugated to a marker for detection Information from the assays can be made quantitative with the right controls Requirement that the protein is denatured prior to detection

A researcher is working with a protein that contains four subunits of differing molecular weights. If the researcher performs SDS-PAGE, how many distinct bands should he see on the gel?

Two One Four Three

Which of the following is a primary factor that dictates how far a protein will migrate during SDS-PAGE?

Number of subunits Size Degree of secondary structure Degree of tertiary structure

Which of the following is true about SDS-PAGE?

Staining with ethidium bromide allows visualization of results The main ingredient in the gel is agarose It is used to anaylze DNA fragments It requires a protein-denaturing gel It separates proteins by charge

As opposed to electrophoresis with a more standard agar gel, what does polyacrylamide gel electrophoresis (PAGE) allow for when working with DNA?

Staining the DNA for visualization Running multiple lanes in one gel Resolution down to DNA strands with single base length differences Running multiple DNA strands in a single gel lane None of these

Which of the following techniques would be most useful to study gene expression?

Western blot Eastern blot Southern blot Northern blot

Which of the following probes are most commonly used in southern blotting?

Nucleic acids Biotin-binding proteins Phosphorous-32 Antibodies

Quiz/Test Summary

Title: Lab Techniques: Electrophoresis And Blots

Questions: 10

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