Lab 10: Molecular Methods 2 Flashcards
What is gel electrophoresis used for in molecular biology?
To separate DNA fragments by size in electric current across agarose gel
How does DNA migrate during electrophoresis?
DNA moves toward the positive electrode because it is negatively charged
What determines how far DNA fragemnts move through an agarose gel?
Their size: smaller fragments move faster and travel farther than large ones
What chemical is used to visualize DNA bands in the gel?
Ethidium bromide
Why must you wear gloves when handling ethidium bromide?
It is a mutagen because it intercalates with DNA
What size fragment indicates a postive PCR result for helicobacter?
A 375 base pair DNA fragment
What is the function of a DNA ladder in gel electrophoresis?
It acts as a molecular weight marker to compare the sizes of DNA fragments
What is murine norovirus?
A common viral infection in lab mice, usually as asymptomatic in healthy mice, but harmful in immunodeficient mice
What is important to identify MNV in research mice?
Infected mice can silently shed virus and spread it to others in the colony
What diagnostic method is used to detect MNV?
Indirect ELISA
What does an indirect ELISA detect?
Antibodies in the serum that bind to a specific antigen coated on the plate
What indicates a postive ELISA result?
A color change to blue/green in the well adding TMB substrate
What is the purpose of the conjugate in ELISA?
It is an enzyme linked anti IgG that binds to mouse antibodies attached to the antigen
What role does TMB substrate play in ELISA?
It reacts with the enzyme in the conjugate to produce a visible color change
Why are multiple wash steps important in ELISA?
To remove unbound antibodies or conjugates, reducing background noise
Why is it beneficial to store PCR products at -20 degrees?
It allows the experiment to be paused and completed later without degradation
