Quiz 6

Compared to cells of a normal tissue, which of the following occurs less frequently in cells within a solid tumor? a. Apoptosis b. Necrosis c. Cell division d. Miotic recombination e. Stress

a. Apoptosis

Which of the following occurs mainly in S phase of the cell cycle? a. DNA helicase activation b. DNA helicase deposition on DNA at the replication origins c. Assembly of new DNA helicases at replication origins d. Licensing of replication origins e. Chromosome segregation

a. DNA helicase activation

Among the following cancers, one is currently leading in the number of deaths in the United States and in the rest of the world. In the United States, it contributes to cancer mortality more than the next three killing cancers combined. Worldwide, it claims more than 1.5 million lives every year. Which cancer is this? a. Lung cancer b. Breast cancer c. Colon cancer d. Pancreatic cancer e. Stomach cancer

a. Lung cancer

Which of the following is an executioner caspase? a. Caspase-8 b. Caspase-3 c. Caspase-5 d. Caspase-2 e. Caspase-9

b. Caspase-3

The major cyclins and Cdks of vertebrates associated with G1/S Cdk are a. Cyclin D; Cdk4, Cdk6 b. Cyclin E; Cdk2 c. Cyclin A; Cdk2, Cdk1 d. Cyclin B; Cdk1 e. Cyclin D; Cdk2

b. Cyclin E; Cdk2

In general, which of the following sequential barriers to metastasis is the easiest to overcome for cancer cells? a. Vessel entry through acquisition of local invasiveness b. Exit from the blood into a remote tissue or organ c. Survival of cells in the foreign tissue d. Initial growth of cells in the foreign tissue e. Persistence of growth in the remote site

b. Exit from the blood into a remote tissue or organ

Which of the following descriptions does not apply to the Wee1 protein? a. Its loss in fission yeast results in small cell size. b. It activates M-Cdk complexes. c. This protein kinase inhibits Cdk activity. d. The phosphatase Cdc25 dephosphorylates sites phosphorylated by Wee1. e. M-Cdk activates Cdc25 and inhibits Wee1.

b. It activates M-Cdk complexes.

What is true about the kinetochore, a large structure formed at the centromeric region of each eukaryotic chromosome? a. It impedes the attachment of the chromosomes to the spindle poles. b. It captures spindle microtubules in mitosis. c. It can bind one microtubule in an animal cell. d. It is attached to a microtubule by interactions with one copy of the Ndc80 complex. e. It can bind more than10 microtubules in budding yeast.

b. It captures spindle microtubules in mitosis.

Which of the following is an inhibitory extracellular signal for cell proliferation? a. EGF b. TGFβ c. Erythropoietin d. IGF e. PDGF

b. TGFβ

Mutation in which gene is most prevalent in human colorectal cancer cells? a. K-Ras b. β-Catenin c. Apc d. p53 e. MLH

c. Apc

M-cyclins activate Cdks that do what? a. Cdks that stimulate chromosome duplication b. Cdks that trigger progression through Start c. Cdks that stimulate entry into mitosis at the G2/M transition d. Cdks that promote DNA replication e. Cdks that remain at elevated levels until mitosis

c. Cdks that stimulate entry into mitosis at the G2/M transition

Which of the following can lead to p53 stabilization and activation? a. Normoxia b. p53 mutation c. DNA damage d. E6 and E7 viral proteins e. Chromosomal stability

c. DNA damage

The intrinsic pathway of apoptosis dictates that proteins be released from which of the following? a. Endoplasmic reticulum b. Cell membrane c. Mitochondria d. Golgi e. Lysosome

c. Mitochondria

Which of the following events contributes to driving the mammalian cell past the restriction point of the cell cycle? a. Phosphorylation of Cdh1-APC/C by M-Cdk b. Induction of CKIs that target S-Cdks c. Repression of E2F gene expression by active E2F protein d. Dephosphorylation of Rb by G1-Cdk, G1/S-Cdk, and S-Cdk

c. Repression of E2F gene expression by active E2F protein

How is Cdc20-APC/C similar to Cdh1-APC/C? a. They are both active throughout interphase. b. They are both inhibited by M-Cdk. c. They both inhibit M-Cdk activity. d. They are both activated suddenly at the onset of mitosis. e. They are both inactivated soon after anaphase.

c. They both inhibit M-Cdk activity.

What is the principal function of mitogens? a. To stimulate cell growth b. To promote cell survival c. To stimulate cell division d. To induce cell death e. To suppress apoptosis

c. To stimulate cell division

What is the most common cancer in humans? a. Sarcoma b. Leukemia c. Myeloma d. Lymphoma e. Carcinoma

e. Carcinoma

In cells irradiated with ultraviolet light, where is cytochrome-c located? a. Mitochondria b. Golgi c. Endoplasmic reticulum d. Nucleus e. Cytosol

e. Cytosol

Which protein is NOT encoded by a proto-oncogene? a. Src b. Ras c. EGF receptor d. Myc e. E-cadherin

e. E-cadherin

Which characteristic is among the hallmarks of cancer cells? a. Maintenance of the limits to cell proliferation b. Unaltered cell metabolism c. Altered homeostasis that results in cells dividing at a faster rate, inducing apoptosis d. Manipulation of the tissue environment, inducing an immune response e. Evasion of cell-death signals

e. Evasion of cell-death signals

What is a nonpreventable cause of cancer? a. Cigarette smoke b. UV radiation c. Viruses d. Diet e. Hereditary predisposition

e. Hereditary predisposition

Which of the following is NOT a carcinogenic agent? a. X-rays b. UV light c. Tobacco d. Viruses e. Inherited genetic defect

e. Inherited genetic defect

What is the most common mechanism behind the conversion of Ras into Ras oncogenes? a. Gene amplification b. Regulatory mutation c. Chromosome rearrangement d. Deletion in coding sequence e. Point mutation in coding sequence

e. Point mutation in coding sequence

Which of the following proteins activates the mitochondrial pathway of apoptosis? a. The tumor suppressor protein Bcl2, when activated in response to extensive DNA damage. b. The BH3-only protein Bid, when cleaved by the initiator caspase-9 (from the extrinsic pathway). c. The anti-IAP protein XIAP, when activated by dephosphorylation. d. The BH3-only protein Puma, when activated by phosphorylation. e. The BH3-only protein Bad, when activated by dephosphorylation.

e. The BH3-only protein Bad, when activated by dephosphorylation.