The following gel represents RNA extracted by four students (1-4)  in a lab. Who was most successful in extracting RNA?

During RNA extraction, you isolate phase A. Your friend repeats the same extraction protocol as you, but isolates phase B. Both of you run the respective phases on the gel to detect RNA.  Which of you is most likely to be successful in RNA isolation? 

During SDS-PAGE electrophoresis, proteins are separated based on size only.

A supercoiled plasmid will run faster compared to its linearized form, because it is more compact.

Protein samples from three patients (1,2 and 3) were separated by SDS-PAGE and subjected to immunoblot analysis.  The blot was incubated with antibodies specific for B-actin and VEGF proteins. Why was the blot probed with antibodies specific for B-actin? Pick all correct answers for complete credit.

The following plasmid was inserted into a bacterial cell and its presence was confirmed.  However, the plasmid failed to replicate inside the cell.  Which of the following answers could best explain the reason for this failure?  

The following steps of a PCR are out of order.  What is the correct order of events that need to occur to amplify DNA?

A cell that has received the following plasmid could not survive in the presence of the antibiotic, Ampicillin.  What could be a possible explanation for this?

What does “X” represent in the following picture?  

Compare Samples A and B. Which sample has pure RNA?