inhibition of an enzyme. as) 35) Which of the following places the steps in the
ID: 255692 • Letter: I
Question
inhibition of an enzyme. as) 35) Which of the following places the steps in the PCR procedure ir 35) 1) Incubate at 94"C to denature DNA strands 2) Incubate at 72'C for DNA synthesis 3) Incubate at 60 C for primer hybridization A) 1, 3,2 B) 1,2,3 ?) 3; 1,2 C)3,2.1 D) 2: 13 separate sheet of oose ONEquestion (either 036 or 037) and write your answer in the space provided or on a per. EORE test describe () purpose, (a) methods and (0) mechanisms behind the test using the following KEYWORDS Underline the KEYWORDS in your sentences 36) Regarding Ames test describe () 1. carcinogen spontaneous mutation 2experimental sample 3. control 4. a plate of media lacking histidine 5. Salmonella 6Explanation / Answer
AMES TEST PURPOSE:It is commonly employed method which uses bacteria to test whether the given chemical causes mutation in the DNA of the test organism.In technical terms,it is a biological assay to assess mutagenic potential of chemical compound.A positive test shows that the chemical is a carcinogen.
METHODS OF AMES TEST:Ames test was intially developed using agar plates.
A popular alternative is the fluctuation method which uses a plate of media lacking histidine.
Treat and wash method for plant extract containing quercetin.
AMES TEST PROCEDURE:
In this test salmonella typhimurium strain is used which is also a mutant.This strain of bacteria cannot grow and develop without histidine aminoacid even if the evnviroment and temperature is correct.But here as we are considering this for chemical mutagens we use his- strain of bacteria.This cannot grow on normal media plate.But if the chemical mutagen is added to the plate then it will turn the his- Gene to his +gene due to mutagenic chemical compound.
Now due to this mutation,the bacterial strain will produce their own histdine which can grow in the plate.
This mutation is called back mutation.But this is not that simple because some chemicals which are non mutagens become mutagenic.In order to obserb that the rat liver extract is mixed with nuterient media and the bacterial sample is innoculated.But from this idea the negative test will not show any such growth but it may show because of spontaneous mutation.So this can give us false positive result.
Therefore in order to study the difference between spontaneous mutation and mutagencity.
If the bacterial colony is scattered they show that bacteria is present because of spontaneous mutation but at the same time we should check the media plate.If it is blank,it means that chemical is non mutagenic.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.