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?

TLS Online TPP Program

#Question id: 15777

#Unit 5. Developmental Biology

Which of the following is not a property of the progenitor cell?

TLS Online TPP Program

#Question id: 15778

#Unit 5. Developmental Biology

Stem cell regulation is highly influenced by the microenvironment that surrounds a stem cell and is known as the

TLS Online TPP Program

#Question id: 15779

#Unit 5. Developmental Biology

During stem cell regulation extracellular mechanisms leading to intracellular changes that regulate stem cell behaviour. Which of the following is not consider as extracellular mechanisms for stem cell regulation?

TLS Online TPP Program

#Question id: 15780

#Unit 5. Developmental Biology

In drosophila, the somatic cells of the hub are able to regulate stem cell proliferation by secreting the paracrine factor Unpaired onto the cells attached to them. Unpaired activates the JAK-STAT pathway in the adjacent germ stem cells to specify their self-renewal. Those cells that are distant from the paracrine factor cannot receive this signal, they begin their differentiation into the sperm cell lineage. This means hub cells act as

TLS Online TPP Program

#Question id: 15781

#Unit 5. Developmental Biology

Chemical regulation of stem cells takes the form of secreted proteins from surrounding cells that influence stem cell states and progenitor differentiation through endocrine, paracrine, or juxtacrine mechanisms. These signaling factors:

TLS Online TPP Program

#Question id: 15782

#Unit 5. Developmental Biology

Adult cells may be reprogrammed to gain pluripotency by modifying the genes namely