Author: mfadmin

Ames Test,”demonstrates that carcinogens (cause cancer) are mutagens (alter DNA)Ames introduced a mutation into a single gene that required Histodine Biosynthesis. This strain of bacteria called His-Auxotroph.Have to add histodine b/c cells can’t make it on its own. Wanted to see what it takes to get cells from His-auxotroph to His-prototroph. These cells have very specific type of genetic mutation, so added compound must be specific mutagen that will mutate DNA at high enough frequency that mutation you’ll get will be able to restore to the original mutationif strong mutagen, lots of coloniesif weak or poor mutagen, will not see anything(a lot of compounds, if first incubated with liver extract

Biology

Average Rating 0 out of 5 stars. 0 votes.You must log in to submit a review.Ames Test,”demonstrates that carcinogens (cause[…]

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“You’re performing the Ames test on two known carcinogens; Benzo(a)pyrene (BaP) and methyl nitrosourea (MNU). If you treat His-Salmonella with MNU, you generate many His+ colonies. In contrast, if you treat His auxotrophic Salmonella with BaP, you generate no His prototrophs. However, if you first incubate the BaP with a liver extract before adding it to the His auxotroph Salmonella, you generate many His prototrophs. How do BaP and MNU differ?”

Biology

Average Rating 0 out of 5 stars. 0 votes.You must log in to submit a review.“You’re performing the Ames test[…]

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Benzo(a)pyrene,”when you ingest it, will have a hard time excreting it b/c not water solubleepoxide intermediate reacts very strongly w/ Guanine (makes covalent bond w/ amino group)no enzyme to cleave bondModified Guanine has distorted structure in DNA double helix–if not removed before DNA replication takes place (p53’s job), it’s distortedDNA polymerase will not pair it with C-it will pair it with A (G-A mismatch)Cell keeps G and converts opposite T to C (which is good, but doesn’t always happen)Some cells throw out modified G and replace it with T. Original G on DNA sequence, converted to T(A-T basepair

Biology

Average Rating 0 out of 5 stars. 0 votes.You must log in to submit a review.Benzo(a)pyrene,”when you ingest it, will[…]

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