Lab 8 Quiz – Microbiology (ASSURED A) 100% CORRECT GRADED A+ | LATEST SOLUTIONS |

Lab 8 Quiz – Microbiology (ASSURED A) 100% CORRECT GRADED A+ | LATEST SOLUTIONS | Question 1 The word ‘antigen’ is actually a combination for what two words? Your Answer: Antibody pathogen Antibody-generating Step-by-Step explanation The human immune system is adapted to recognise and eliminate particles that do not belong to the human body. This ensures that outside microbes cannot cause infection in the body. For this, the body recognise specific "epitopes" and make antibodies against the molecule. These antibodies bind specifically to a particular molecule and help in their elimination. Note that body cannot differentiate between harmful and harmless foreign molecules. It makes antibodies against every molecule that has particular characteristics such as appropriate size and shape, usually proteinaceous. These foreign particles (can be even pollens) can trigger the immune system and the immune system makes antibodies against them. Therefore, these molecules are capable to "generating antibodies" in the body and therefore, are known as "antibody generating" molecules or "antigens". Question 2 For the ELISA assay depicted below, which step (A-E) contains only specifically bound antigens (aka a 'pure' population)? Your Answer: In step C you see only specifically bound antigens, aka a pure population. In step B you see specific and non-specific antigens, but then the wash step removes the non-specific or unbound antigens, leaving only the specific antigen which is present in step 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 What would happen in terms of the colorimetric readout if you forgot to do the wash step after Step D (above)? Your Answer: If you forgot to do the was step after Step D, all the wells would have a dark color. This is because 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 Question 4 washed away, all the wells would react the same. 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. In a western blot are separated based on its size. Your Answer: Proteins proteins Question 5 When setting up a western blot, what is the purpose of the blocking step post-transfer? Your Answer: The blocking step post-transfer prevents non-specific binding of the antibody. You only want the antibody to bind to its specific target. Blocking prevents non-specific binding of the antibody—you only want the antibody to bind to its specific target.