631. What would happen if serum is omitted from the ELISA, but all other steps remain same?
A. Anti-human Ig-conjugate would not bind and be washed away
B. The OD values would be nearly the same as the assay control
C. Both (a) and (b)
D. Anti-human Ig-conjugate would bind non-specifically to the ELISA plate

632. RAST test (radio allergosorbent test) is often used to detect
A. antibodies associated with allergies (IgE)
B. antigen associated with allergies (IgE)
C. bacteriophages
D. None of the above

633. What would happen if the anti-human Ig-conjugate is not washed free of the well before the substrate is added?
A. The ELISA would not develop when the substrate was added
B. The ELISA would develop normally
C. All wells would show uniform over-development due to unbound and excess anti-human Ig enzyme conjugate
D. None of the above

634. An antigen preparation and an antibody preparation are tested by immunodiffusion. Three bands are found, indicating that
A. there was more than one antigen
B. the antibody was impure
C. the temperature was too high
D. there was one antibody and one antigen

635. Immunoelectrophoresis techniques are designed to separate the mixture components from each other by using electrophoresis
A. prior to reaction with antibody
B. prior to reaction with antigen
C. after reaction with antibody
D. after reaction with antigen

636. Which of the following is a positively charged matrix for ion exchange chromatography?
A. CM cellulose
B. DEAE cellulose
C. Phosphocellulose
D. None of these

637. Which of the following is an immunoelectrophoresis technique?
A. Two-dimensional immunoelectrophoresis
B. Counterimmunoelectrophoresis
C. Coimmunoelectrophoresis
D. Both (a) and (b)

638. Cholesterol is somewhat amphipathic due to
A. the single hydroxyl along with the hydrocarbon nature of the remainder of the molecule
B. the long branched hydrocarbon along with the four hydrocarbon rings
C. the five-methyl groups along with the hydrocarbon chain
D. the three six-membered rings along with the single five-membered ring

639. Bacteriorhodopsin
A. absorbs light and pumps protons
B. is an integral membrane protein
C. contains primarily alpha-helical residues
D. all of the above

640. In active transport, the membrane structure that functions is
A. cholesterol
B. integral proteins
C. carbohydrates
D. hydrophobic molecules