Question

12. In the gel electropboresis procedure we added ethidium bromide to the gel in order to Visualize the DNA. What specific health hazard is associated with this chemical? 13. Briefly describe one reason a non-biologist might want to identify a fungal sample to the species level. 14. After you weigh a fungal sample for DNA extraction; what is the first step towards isolating the DNA? 15. When handling a micropipet, why is it necessary to always hold it upright (tip down)? 16. Imagine you are about to use the P20 micropipette, calibrated to deliver volumes between 2 and 20 ul. You would like use it to transfer a volume of 1 ul. You are an expert pipettor. Can you be confident in your pipetting accuracy? Why or why not?

Answer 1

12. Ethidium Bromide (EtBr) is considered hazardous potent mutagen that can cause cancer (carcinogenic). EtBr can enter the human body via the exposed skin surface, eyes, mucous membranes. Interestingly, there has been little or no proof of EtBr to have caused cancer in humans and also is Ames negative (Ames test is a test to find out whether a molecule can induce mutations). Although there is a prossibility that a derivative of EtBr might bring about some mutations after it comes in contact with metabolic enzymes, but that too needs exposure to high quantities of EtBr which is of course not the case in molecular biology laboratories!