There are serum samples from people who tested positive for the SARS-CoV2 virus and have now recovered. What is one explanation for why they might have such different levels of antibody?

1) SDS PAGE gels can be probed with NBT/BCIP to perform an immunoblot true/ false 2) the direction of migration of protiens through a matrix is due to most proteins in natur having a net negative charge  true/false 3)  PBST  is a buffer that is used for blocking the membrane during immunoblotting. true/false 4) the buffer used during for transferring proteins to nitrocellulose methanol. true/false 7) The size of the pores of a polyacrylamide gel dcreases as concentrations of polyacrylamide increases. True or false 10) The secondary antibody used in laboratory for western blotting is conjugated to which enzyme  A) Alkaline decarboxylase B) GAPDH C) Alkaline Phosphatase D) Horseeradish peroxide 13) In protien electrophroresis, what reagent present in the sample buffer is used to eliminate difference in the charge densities of protein A) SDS B) 2- mercaptoethanol C) Tris-HCL pH6.8 D) Tris- HCL PH 8.8

Addition of immunoglobulin G (IgG) specific for hemoglobin to a solution of hemoglobin results in the formation of a red precipitate. In contrast, addition of the Fab fragments from this antibody to hemoglobin results in no such precipitate. What could explain this difference in results? Treatment with papain produces Fab fragments with different antigen specificity than the original IgG molecule. IgG can simultaneously bind two different antigens, whereas an Fab fragment can only bind one antigen at a time. The Fab fragments preferentially bind to other Fab fragments rather than to hemoglobin. The hemoglobin molecule antibody-binding sites can bind IgG molecules, but cannot bind Fab fragments.

How could immunoglobulin cross-reactivity between foreign antigens and host cell antigens result in damage to the host?