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

Describe three ways that cancer cells differ from normal cells.

Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related toa. disruption of mitotic spindle formation.b. suppression of cyclin production.c. myosin denaturation and inhibition of cleavage furrow formation.d.inhibition of DNA synthesis.

One difference between cancer cells and normal cells is that cancer cellsa. are unable to synthesize DNA.b. are arrested at the S phase of the cell cycle.c. continue to divide even when they are tightly packed together.d. cannot function properly because they are affected by density-dependent inhibition.

Evaluate each of the following defects. Which could lead to uncontrolled growth in cancer? Select True or False for each statement.T/FThe overexpression of MPF activity.T/FA nonfunctional Rb protein.T/FThe overexpression of G1 cyclin.T/FA nonfunctional E2F protein.

Compare and contrast the effects of removing growth factors from asynchronous cultures of human cells that are normal and those that are cancerous.

Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?a. Proto-oncogenes first arose from viral infections.b. Proto-oncogenes are mutant versions of normal genes.c. Proto-oncogenes are genetic 'junk.'d. Proto-oncogenes normally help regulate cell division.

Scientific Thinking The study described in Module 8.10 was purely observational; there were no controlled groups. Imagine that you are an oncologist. Design a hypothesis-driven study to determine whether mastectomy improves breast cancer survival over lumpectomy. What are your control groups? Would such a study be ethical to undertake? Why or why not?