MIP302 Final Exam Questions and
Answers Graded A+
What are the steps of the indirect ELISA? - Answer-1. target antigen is added to the
microtiter wells and it binds to well surfaces
2. the sample is added to the wells, and if there is any antibody specific to the antigen, it
will bind (primary antibody)
3. the secondary antibody is added, which binds to the primary antibody
4. an enzyme is covalently bound to the secondary antibody and will produce a color
change if the appropriate substrate is present
Note: washing occurs between each step to remove unattached antigen/antibody
(decreases background interference and improves result accuracy)
Indirect = secondary antibody carries reporter enzyme
Antigen capture ELISA is also sometimes called a ________________ ELISA - Answer-
sandwich
non-specific binding - Answer-Antibody indiscriminately binds to any binding site not
filled
antibody capture ELISA - Answer-an antibody is captured by the antibody bound to the
solid matrix (often used on serum)
titer
Ex: you make serial dilutions and add 0.1 mL of each to the wells. The endpoint is the
well containing 1/128 dilution of the sample - Answer-reciprocal of the total dilution of
the endpoint
Ex: (1/128) * 0.1 = (0.1/128) = 1/1280
reciprocal --> 1280
endpoint - Answer-the last dilution in an ELISA test that reads positive (color change)
why are capture ELISA's also called sandwich ELISA's? - Answer-because the target
antibody or antigen is sandwiched between 2 antigens or antibodies
What 2 components are common to all ELISAs? - Answer-an enzyme-substrate
complex and an enzyme that facilitates the color change (the reporter)
What is the difference between direct and indirect ELISA? - Answer-direct: detects
antigens w/ 1 antibody
indirect: detects antibodies or antigens with a primary and secondary antibody
, how does blocking inhibit false positive results? - Answer-prevents nonspecific binding
Why are primary and secondary antibodies in the same ELISA from different animal
species? - Answer-to ensure no cross-interactions and correct sandwiching
imagine you're using ELISA to test blood for the presence of a virus that causes Hep B.
You'd assay for the presence of viral ___________ in the blood. - Answer-antigen
imagine you're using ELISA to test blood to determine if a person has been exposed to
HIV. You'd assay for the presence of ___________ in the blood. - Answer-antibodies
What equation determines the relationship between number of phage in an original
sample, the number of phage in the diluted sample, and the dilution used? - Answer-
#phage (or cells) in diluted sample (PFUs) = #phage or cells/mL in original sample *
dilution * volume used
chemotherapeutic agents - Answer-chemicals administered internally to the host for the
control of microbial infections; used to control fungal, protozoal, and bacterial infections
Bacteriocidal - Answer-agent that kills bacteria
Bacteriostatic - Answer-inhibits bacterial growth
True antibiotic - Answer-a natural substance made by one organism to kill a
microorganism
antibiotic - Answer-A chemical secreted by a living organism that kills or reduces the
reproduction rate of other organisms
origins of penicillin - Answer-Penicillium mold secretions
origins of polymyxin B - Answer-Bacillus polymyxa bacteria
origins of streptomycin - Answer-Streptomyces bacterial genus
sulfa drugs - Answer-drugs that are synthesized in laboratories; chemotherapeutic
agent but NOT a true antibiotic
selective toxicity - Answer-a drug's ability to selectively find and destroy pathogens
without damaging the host
5 principle mechanisms by which chemotherapeutic agents work - Answer-1. inhibition
of cell wall synthesis
2. inhibition of protein synthesis
3. inhibition of nucleic acid synthesis
4. cell membrane disruption
5. metabolic antagonism
Answers Graded A+
What are the steps of the indirect ELISA? - Answer-1. target antigen is added to the
microtiter wells and it binds to well surfaces
2. the sample is added to the wells, and if there is any antibody specific to the antigen, it
will bind (primary antibody)
3. the secondary antibody is added, which binds to the primary antibody
4. an enzyme is covalently bound to the secondary antibody and will produce a color
change if the appropriate substrate is present
Note: washing occurs between each step to remove unattached antigen/antibody
(decreases background interference and improves result accuracy)
Indirect = secondary antibody carries reporter enzyme
Antigen capture ELISA is also sometimes called a ________________ ELISA - Answer-
sandwich
non-specific binding - Answer-Antibody indiscriminately binds to any binding site not
filled
antibody capture ELISA - Answer-an antibody is captured by the antibody bound to the
solid matrix (often used on serum)
titer
Ex: you make serial dilutions and add 0.1 mL of each to the wells. The endpoint is the
well containing 1/128 dilution of the sample - Answer-reciprocal of the total dilution of
the endpoint
Ex: (1/128) * 0.1 = (0.1/128) = 1/1280
reciprocal --> 1280
endpoint - Answer-the last dilution in an ELISA test that reads positive (color change)
why are capture ELISA's also called sandwich ELISA's? - Answer-because the target
antibody or antigen is sandwiched between 2 antigens or antibodies
What 2 components are common to all ELISAs? - Answer-an enzyme-substrate
complex and an enzyme that facilitates the color change (the reporter)
What is the difference between direct and indirect ELISA? - Answer-direct: detects
antigens w/ 1 antibody
indirect: detects antibodies or antigens with a primary and secondary antibody
, how does blocking inhibit false positive results? - Answer-prevents nonspecific binding
Why are primary and secondary antibodies in the same ELISA from different animal
species? - Answer-to ensure no cross-interactions and correct sandwiching
imagine you're using ELISA to test blood for the presence of a virus that causes Hep B.
You'd assay for the presence of viral ___________ in the blood. - Answer-antigen
imagine you're using ELISA to test blood to determine if a person has been exposed to
HIV. You'd assay for the presence of ___________ in the blood. - Answer-antibodies
What equation determines the relationship between number of phage in an original
sample, the number of phage in the diluted sample, and the dilution used? - Answer-
#phage (or cells) in diluted sample (PFUs) = #phage or cells/mL in original sample *
dilution * volume used
chemotherapeutic agents - Answer-chemicals administered internally to the host for the
control of microbial infections; used to control fungal, protozoal, and bacterial infections
Bacteriocidal - Answer-agent that kills bacteria
Bacteriostatic - Answer-inhibits bacterial growth
True antibiotic - Answer-a natural substance made by one organism to kill a
microorganism
antibiotic - Answer-A chemical secreted by a living organism that kills or reduces the
reproduction rate of other organisms
origins of penicillin - Answer-Penicillium mold secretions
origins of polymyxin B - Answer-Bacillus polymyxa bacteria
origins of streptomycin - Answer-Streptomyces bacterial genus
sulfa drugs - Answer-drugs that are synthesized in laboratories; chemotherapeutic
agent but NOT a true antibiotic
selective toxicity - Answer-a drug's ability to selectively find and destroy pathogens
without damaging the host
5 principle mechanisms by which chemotherapeutic agents work - Answer-1. inhibition
of cell wall synthesis
2. inhibition of protein synthesis
3. inhibition of nucleic acid synthesis
4. cell membrane disruption
5. metabolic antagonism
