The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species. Which of the five common ancestors, labeled V—Z, has been most successful in terms of the percent of its derived species that are extant?

#Question id: 1396

#Unit 4. Cell Communication and Cell Signaling

Trks are:

a. endonucleases.        b. transmembrane receptors.   c. proteases.     d. protein kinases.      

#Question id: 1397

#Unit 4. Cell Communication and Cell Signaling

The vertebrate equivalent of CED-9 is:

#Question id: 1398

#Unit 4. Cell Communication and Cell Signaling

Which of the following properties is (are) characteristic of a benign tumor?

a. well differentiated              b. localized to tissue of origin             c. metastatic               

d. promotes angiogenesis        e. surrounded by a fibrous capsule

#Question id: 1399

#Unit 4. Cell Communication and Cell Signaling

Loss-of-function mutations in which of the following genes typifies colorectal carcinomas?

a. myc              b. K-ras                       c. p53              d. APC

#Question id: 1400

#Unit 4. Cell Communication and Cell Signaling

Which property is shared by malignant tumor cells and transformed cells in culture?

a. reduced growth factor requirement                        b. attachment-dependent growth

c. loss of actin microfilaments                                    d. altered morphology

#Question id: 1401

#Unit 4. Cell Communication and Cell Signaling

Which of the following are proto-oncogenes?

a. fos               b. myc             c. p53              d. ras               e. Rb