1o. We used an auxotrophic strain of bacteria and screened for reversion to a pr

Question

1o. We used an auxotrophic strain of bacteria and screened for reversion to a prototrophic strain. Could we determine the mutagenicity of your treatments using a prototrophic strain and screening for the generation of an auxotrophic strain? In your answer be sure you support your reasoning. 11. Benzo[a]pyrene is a hydrocarbon found in smoke from the burning of organic material and in food that is charbroiled. (It is a component of coal tar and was the causative agent in the increased incidence of cancer in chimney sweeps studied in the early 1900's). The Ames Test as we used it, does not positively identify Benzo[a]pyrene as the highly carcinogenic agent we now know it to be. However, adding a mammalian liver fraction (representing a milieu of liver enzymes), results in a positive Ames test result for Benzo[a]pyrene. a. Explain why such a False negative result could occur, using the test as we did for this lab. b. Explain how adding liver fraction to the Ames test changes the result.

Explanation / Answer

Yes, the phototrophic organism grow in normal media they have all the necessary compound s for their growth. If any mutagen added to the media it makes a mutation in the bacteria but it also grow their. Then we have to isolate each colonies and put in the minimal media which organisms are not survive in that minimal media. It takes lot
of work to find out the mutatgenicity.

A. Benzopyrene is a not a carcinogen in the normal state or in lab condition only when
it enter in to human body it turns to carcinogen. Thats why test shows false negative.

B. Liver fraction has an enzyme which react to benzopyrene and activate to carcinogen.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.