True/False with Justification. Indicate whether the statement is true or false. Then, regardless of whether you choose true or false, explain your reasoning. The Wee1 kinase could be considered the product of a tumor suppressor gene. A cell containing a mutant form of the Rb protein that cannot be phosphorylated would be blocked at the G1 -> S checkpoint.

Some cancer cells are insensitive to typical chemotherapy. Research into the mechanisms underlying this insensitivity uncovered an ability by these cells to pump the treatment drug out of the cell against its concentration gradient. Additional drugs have been developed that inhibit the pump, thus trapping the chemotherapeutic agent inside to promote cancer cell destruction. The Figure shows what happens when two types of cells are treated with a 3H-labeled anti-cancer drug, paclitaxel. Which set of cells (A or B) would be described as resistant to the cancer treatment? Explain your answer. What type of transport are the resistant cells using?

Some cancer cells are insensitive to typical chemotherapy. Research into the mechanisms underlying this insensitivity uncovered an ability by these cells to pump the treatment drug out of the cell against its concentration gradient. Additional drugs have been developed that inhibit the pump, thus trapping the chemotherapeutic agent inside to promote cancer cell destruction. The Figure shows what happens when two types of cells are treated with a 3H-labeled anti-cancer drug, paclitaxel. Two additional drugs, imatinib and nilotinib, are evaluated for their ability to overcome the cancer cells ability to pump out the chemotherapeutic agent. An asterisk (*) indicates a statistically significant difference from the cells receiving paclitaxel alone. Do the additional drugs seem to the effective in over-coming the pump? Which set of graphs (A or B) best supports your answer? Explain your answer.

Figure 37.5 Heat shock proteins (HSP) are so named because they help refold misfolded proteins. In response to increased temperature (a “heat shock"), heat shock proteins are activated by release from the NR/HSP complex. At the same time, transcription of HSP genes is activated. Why do you think the cell responds to a heat shock by increasing the activity of proteins that help refold misfolded proteins?

Explain the difference between a proto-oncogene and a tumor suppressor gene.

Cell specializations are usually a modification or elaboration of one of the basic cell functions. (True or fa1se?)

Benign tumors: a. are noncancerous growths that do not spread to other tissues b. do not contain mutations c. are malignant and clonal in origin d. metastasize to other tissues e. none of these

A gene that codes for a positive cell cycle regulator is called a(n) _______. a. kinase inhibitor b. tumor suppressor gene c. proto-oncogene d. oncogene

Figure 17.15 In 2011, the United States Preventative Services Task Force recommended against using the PSA test to screen healthy men for prostate cancer. Their recommendation is based on evidence that screening does not reduce the risk of death from prostate cancer. Prostate cancer often develops very slowly and does not cause problems, while the cancer treatment can have severe side effects. The PCA3 test is considered to be more accurate, but screening may still result in men who would not have been harmed by the cancer itself suffering side effects from treatment. What do you think? Should all healthy men be screened for prostate cancer using the PCA3 or PSA test? Should people in general be screened to find out if they have a genetic risk for cancer or other diseases?

A scientist observes a mutation in the transmembrane region of EGFR that eliminates its ability to be stabilized by binding interactions during dimerization after ligand binding. Which hypothesis regarding the effect of this mutation on EGF signaling is most likely to be correct? EGF signaling cascades would be active for longer in the cell. EGF signaling cascades would be active for a shorter period of time in the cell. EGF signaling cascades would not occur. EGF signaling would be unaffected.