q8 - raji_321

[ArchivalUser]

A patient who has never had chickenpox wants to visit her sister, whose daughter currently has the disease. In order to determine if she has antibodies to the varicella zoster virus, which of the following tests could be performed?
A. ELISA
B. Northern blot
C. PCR reaction
D. Southern blot
E. Subtractive hybridization

[ArchivalUser]

D?

[ArchivalUser]

a..

[ArchivalUser]

The correct answer is A. An enzyme-linked immunosorbent assay (ELISA) would be used to determine antibody levels to a particular virus. Viral protein is bound to a microtiter plate and the patient's serum serially diluted across the plate. If specific antibodies for the virus are present, they bind to the virus. The amount of bound antibody is quantitated, using an enzyme-coupled reaction that produces a visible pigment in proportion to the amount of bound antibody. A similar test is used to determine exposure to HIV.

Northern blots (choice B) are used to determine RNA levels in a cell.

PCR reactions (choice C) are useful in amplifying small pieces of DNA for sequencing, cloning, or microsatellite DNA mapping.

Southern blots (choice D) are used to study genomic DNA.

Subtractive hybridization (choice E) is a technique used to identify tissue or organ specific genes by "subtracting" out RNA from a closely related cell type, leaving behind the RNAs from genes that are transcribed only in that cell type.