611. Structures of anti-PCP antibody shows that the tight binding of PCP to the antibody is primarily due to
A. hydrophobic forces
B. electrostatic forces.
C. Van der Waals forces.
D.none of these

612. Antigenic determinants bind to which portions of an antibody?
A. Variable regions
B. Constant regions
C. Only light chains
D. Only heavy chains

613. The humoral immune response relies on the production of soluble proteins called
A. antibodies
B. macromolecules
C. lymphocytes
D. none of these

614. The human IgG class of antibodies is divided into
A. five IgG classes
B. two IgG classes
C. three IgG classes
D. four IgG classes

615. Agarose gel electrophoresis and pulsed field gel electrophoresis may be used to resolve respectively
A. 2000 kb and 20kb DNA
B. 1000 kb and l0kb DNA
C. 20 kb and 2000 kb DNA
D. 10 kb and 1000 kb DNA

616. The IPTG is a gratuitous inducers of (β-galactosidase, and x-gal is a chromogenic substrate. When α-complementation occurs which colour is produced?
A. Blue
B. White
C. Brown
D. No colour is produced

617. The competitive immunoassay can be used
A. to detect very small amounts of antigen
B. to detect antibody associated with allergies (IgE)
C. both (a) and (b)
D. commonly to detect trace amounts of drugs.

618. Which of the following is an immunodiffusion test?
A. Double-diffusion
B. Gel diffusion
C. Ouchterloney technique
D. All of these

619. In Counter immunoelectrophoresis
A. electrophoresis will drive the antibody and antigen parallel to each other
B. electrophoresis will drive the antibody and antigen toward each other
C. the antibody will migrate towards anode
D. the antibody will migrate towards cathode

620. What is the ELISA test intended to measure?
A. Antibody to HIV only
B. Antigen to HIV only
C. Presence of free, circulating virus in the patient
D. Antibodies directed against HLA molecules