BIOD 171 Essential Microbiology Lab8 exam.

BIOD 171 Essential Microbiology Lab8 exam. Question 1 3 / 3 pts The word ‘antigen’ is actually a combination for what two words? Your Answer: combination of antibody and gen means which produces . so it means when antigen enters the body produces of antibodies will start Antibody-generating Question 2 3 / 3 pts For the ELISA assay depicted below, which step (A-E) first contains only specifically bound antigens (aka a 'pure' population)? Your Answer: C Specifically bound antigens are present in step C. Specific and non-specific antigens are present in B but then the wash step removes the non-specific (unbound) antigens, leaving only the specific population seen in step C. Question 3 2 / 4 pts What would happen in terms of the colorimetric readout if you forgot to do the wash step after Step D (above)? This study source was downloaded by from CourseH on :17:07 GMT -05:00 Your Answer: the unbound secondary antibody will not be washed away, so we may have false positive result All of the wells would have a dark color. The intensity of the readout is dependent upon the amount of the labeled secondary antibody present in the well. Since the unbound secondary antibody was not washed away, all wells would react equally. Question 4 2.5 / 2.5 pts A western blot separates proteins based on ______________. Your Answer: Size and molecular mass Size Question 5 2.5 / 2.5 pts When setting up a western blot, what is the purpose of the blocking step post-transfer? Your Answer: it can prevent antibodies from binding to membrane non specifically Blocking prevents non-specific binding of the antibody—you only want the antibody to bind to its specific target. Question 6 1.25 / 2.5 pts When developing a western blot what two factors influence the intensity of the band? Your Answer: type of membrane , intensity of current supplied Both the amount of protein loaded as well as the duration (time) of development is directly proportional to band intensity.