Understanding ELISA: A Qualitative Approach

What is the primary purpose of using ELISA in this demonstration?

• To measure the pH level of a solution

• To detect the presence or absence of specific antibodies or antigens

• To count the number of cells in a sample

• To determine the concentration of glucose in blood

Why are the wells of the microplate labeled with plus and minus signs?

• To identify the wells containing enzyme-substrate

• To differentiate between the positive and negative controls

• To indicate the wells that should be filled with water

• To mark the wells that will not be used in the experiment

Why are positive and negative controls used in this experiment?

• To test the function of the microplate

• To provide a comparison for the experimental results

• To increase the volume of the samples

• To demonstrate the color change reaction

What is the purpose of incubating the samples at room temperature for five minutes after adding the antigen?

• To allow the antigen to bind to the plastic wells

• To dissolve the antigen completely in the buffer

• To cool down the samples before further processing

• To sterilize the surface of the microplate

What is the significance of tapping the microplate strip onto paper towels?

• To mix the contents of each well

• To remove any air bubbles

• To empty the wells of excess liquid

• To clean the bottom of the microplate

Why is it important to use a fresh pipette tip for each serum sample?

• To speed up the experiment process

• To measure the volume more accurately

• To avoid cross-contamination between samples

• To prevent the pipette from clogging

What is the role of the secondary antibody in this ELISA procedure?

• To directly detect the presence of antigens

• To neutralize any harmful substances in the sample

• To act as a control for the experiment

• To bind to the primary antibody for detection

How many times is the wash procedure repeated after adding the secondary antibody?

• Once

• Four times

• Twice

• Three times

What is the final step before observing and recording the results?

• Adding more serum samples to the wells

• Incubating the samples with enzyme-substrate

• Performing an additional wash with buffer

• Heating the samples to activate the enzyme

What does the presence of a color change in the well indicate?

• The well was not washed properly

• A successful binding of the enzyme-substrate

• Contamination of the sample

• The absence of the target antibody or antigen