11. Cell Division

The difference between benign and malignant tumors is:

a) Malignant tumors do not spread to other sites.

b) Benign tumors have not lost growth control.

c)  Benign tumors have not spread to other sites.

d)  Malignant tumors have not lost growth or control.

Which of the following processes do normal proto-oncogenes typically exhibit?

a)    They normally suppress tumor growth.

b)    They enhance tumor growth.

c)    They stimulate normal cell growth and division.

d)    They are underexpressed in cancer cells.

When activated by signals in the cell, Protein X can stop cells from growing and dividing into new cells. What type of gene codes for Protein X?

a) Oncogene.

b) Tumor-suppressor gene.

c) Protein kinase gene.

d) Protein Vesicle gene.

e) Proto-oncogene.

All your cells contain proto-oncogenes, which can change into cancer-causing oncogenes. Why do cells possess such potential time bombs?