Which of the following is (are) required for splicing to occur?

a. two transesterification reactions

b. intact, naturally occurring introns

c. formation of a lariat like structure 

d. a branch-point G residue

#Question id: 1499

#Unit 4. Cell Communication and Cell Signaling

The normal protein product of the RB gene acts as an:

#Question id: 1500

#Unit 4. Cell Communication and Cell Signaling

Which of the following is not a normal function of p53?

#Question id: 1501

#Unit 4. Cell Communication and Cell Signaling

When a culture of rodent cells is infected with a DNA tumor virus whose gene products bind to p53 and RB, all the cells take on characteristics of malignancy. If the viral gene coding the p53-binding protein is mutated, but that coding for the RB-binding protein is not mutated, how will infected cells respond?

#Question id: 1502

#Unit 4. Cell Communication and Cell Signaling

The textbook states that cells of patients with adenomatous polyposis coli (APC) “contain a deletion of a small portion of chromosome #5, which was subsequently identified as the site of a tumor-suppressor gene called APC.” In which cells of these patients would you expect to find this chromosomal deletion?

#Question id: 1503

#Unit 4. Cell Communication and Cell Signaling

When the genes responsible for familial breast cancer were sequenced, it was found that the polypeptides they encoded contained a zinc finger motif. What does this suggest to you about the normal functions of the products of these genes?

#Question id: 1504

#Unit 4. Cell Communication and Cell Signaling

Tumor-suppressor genes usually act as .......... genes, and oncogenes usually act as ...........  genes.