Following statements are regarding to enzymatic processing of benzo(a)pyrene to a more potent mutagen and carcinogen.

A. Liver enzymes, particularly P-450 enzymes, modify benzo(a)pyrene in a series of reactions, producing 7,8-diol-9,10-epoxide, a highly potent mutagenic species that reacts with DNA primarily at the N2 atom of a guanine base.

B. The adduct, (+)-trans-anti-B(a)P-N2-dG, causes polymerase to insert an A rather than a C opposite the modified G base. Next time the DNA is replicated, a T will be inserted opposite the A, and the mutation will be complete.

C. Potent mutagen majorly causes conversion of guanine (G) to thymine (T) bases, a transition mutation.

D. When this potent mutagen applied to cultured bronchial epithelial cells, activated benzo(a)pyrene induces many mutations, including activating mutations at codons 175, 248, and 273 of the p53 gene.

Which of the following statements are correct?

#Question id: 5051

#Unit 5. Developmental Biology

after the 8-cell stage, the mammalian embryo develops an outer layer (which becomes the fetal portion of the placenta), and an inner cell mass that generates all the cells of embryo. The cells of the inner cell mass are thus said to be-

#Question id: 5052

#Unit 5. Developmental Biology

cell populations within each germ layer expand and differentiate, resident stem cells are maintained within these developing tissues and function to generate cell types with restricted specificity for the tissue in which they reside. these stem cells are-

#Question id: 5053

#Unit 5. Developmental Biology

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#Question id: 5054

#Unit 5. Developmental Biology

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#Question id: 5055

#Unit 5. Developmental Biology

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#Question id: 5056

#Unit 5. Developmental Biology

Cells of the responding tissue must have both a receptor protein for the inducing factor and the ability to respond to the signal. The ability to respond to a specific inductive signal is called as