Chapter 26: Cancer Cells MBA, Cell bio chapter 26 homework, Becker's world of the cell Ch 24, CH 26 - Cancer Cells, Cell bio chapter 26 homework, ch 24 mb, Chapter 23, Chapter 24, chapter 26, Mastering Biology ch26, Cell Biology Chapter 24

Why was the word "usually" included in the first sentence?

1. DNA polymerase n 2. remains intact. 3. DNA polymerase n 4. catalyzes 5. synthesis of a new, error-free stretch 6. DNA polymerase n

Control of the cell cycle must

1. Ensure that events of each phase are carried out in the correct order and at the appropriate time 2. Ensure that each phase is completed before the next one begins 3.Respond to external conditions 3. Respond to external conditions

two interacting mechanisms of the eukaryotic cell cycle (the "machine")

1. autonomous clock goes through a fixed cycled over and over again via the synthesis and degradation of cylcins 2. clock is adjusted as needed.

Describe two pieces of evidence supporting the idea that angiogenesis is required for tumors to grow beyond a tiny clump of cells. Drag the terms on the left to the appropriate blanks on the right to complete the sentences.

1. fail to link up to 2. 1-2 mm in diameter 3. become infiltrated with 4. enormous size 5. remain alive and 6. 1-2 mm in diameter 7. become infiltrated with 8. enormous size

restriction point/control point

1st transition point: A point of no return in the cell cycle; once this point passes, a cell is committed to S phase, ability to pass this is influenced by extracellular growth factors. those that do not, enter into G0 and reside there until a signal allows them to reenter G1 and pass through the remaining restriction points

G2-M transition

2nd transition point where the commitment is made to enter mitosis. In some cell types, the cell can be arrested in G2 indefinitely and the cell enters a state analogous to G0, such as frog eggs

Transition point during M phase

3rd transition point :all the chromosomes must be properly attached to the spindle before moving into anaphase, this phase is between metaphase and anaphase, commitment is made to move the two sets of chromosomes into the new cells

In an adult human stem cell that has a total of 48 chromosomes, how many chromatids are present at prophase of mitosis ?

96

In an adult human stem cell that has a total of 48 chromosomes, how many chromatids are present at prophase of mitosis?

96

Design experiments that would allow you to independently detect each of the following: G-protein mediated signal transduction, nitric oxide signal transduction, and calcium ion fluxes.

A variety of valid answers could be obtained, and it is up to the instructor whether or not to accept the validity of the student answers. However, one could use nonhydrolyzable GTP analogs, mimicking of responses with treatment of cells with nitroglycerin, and cameleons as possible answers.

12) The ploidy of cells characteristic of an aneuploid is best represented by which of the following? A) 2n + 1 B) n C) 2n D) 4n E) both choices B and C

A) 2n + 1

16) In a normal cell, cell death typically occurs in which phase of the cell cycle? A) G1 B) S C) G2 D) M E) all of the above

A) G1

5) Which of the following statements regarding cancer is false? A) Rate of cell division is critical. B) Balance between differentiation and proliferation is important. C) As cells become more differentiated, their capacity to divide decreases. D) Balance in cell growth is achieved when division results in no net gain of cells. E) In tumor cells, division and differentiation are uncoupled.

A) Rate of cell division is critical.

27) Which scientist(s) was/were awarded a Nobel prize 50 years after discovering viral oncogenesis? A) Rous B) Epstein and Barr C) Burkitt D) Folkman E) Kaposi

A) Rous

26) The first documentation of a viral infection causing oncogenesis was established with A) Rous sarcoma virus in chickens. B) Epstein-Barr virus in Burkitt's lymphoma. C) hepatitis B in liver cancer. D) HIV in humans. E) human papilloma virus in cervical cancer.

A) Rous sarcoma virus in chickens.

14) The Ames test is characterized by the use of A) auxotrophic Salmonella typhimurium. B) heterotrophic monoploid yeast. C) autotrophic monoploid yeast. D) prototrophic Salmonella typhimurium. E) both choices A and C

A) auxotrophic Salmonella typhimurium.

3) The most frequently encountered category of cancer is A) carcinoma. B) sarcoma. C) lymphoma. D) leukemia. E) both choices C and D

A) carcinoma.

9) The group of proteins associated with the binding of cells to the extracellular matrix are the A) integrins. B) monolins. C) MHC. D) matrix metalloproteins. E) RAS proteins.

A) integrins.

20) Some ________ influence histone modification reactions. A) microRNAs B) histones C) p53 genes D) scaffolding proteins E) tumor suppressors

A) microRNAs

40) Which of the following viruses has not been determined to be associated with a particular type of cancer? A) mimivirus B) hepatitis B virus C) Epstein-Barr virus D) human papilloma virus E) hepatitis C virus

A) mimivirus

18) Judah Folkman used which model to discern the relationship between tumor growth and angiogenesis? A) rabbit eye B) thymus tissue C) bone marrow D) mouse skin E) in vitro cells

A) rabbit eye

The chemical substance 2-acetylaminofluorene (AAF) causes bladder cancer when injected into rats but not guinea pigs. If normal bladder cells obtained from rats and guinea pigs are grown in culture and exposed to AAF, neither are converted into cancer cells. How can you explain these findings?

AAF is a "precarcinogen" that needs to be metabolically activated before it can cause cancer. Rats, but not guinea pigs, contain a liver enzyme that catalyzes the metabolic activation of AAF.

All of the following participate in apoptosis except

APC ubiquitin ligase activity.

Cyclins modulate the progression of cells through the cell cycle by directly

Activating protein kinases that are critical regulators of cell division

Each of the following is a main cause of cancer except

All are causes of cancer.

Each of the following is a cancer a cancer screening procedure except

All are screening procedures.

Each of the following is a cancer a cancer screening procedure except mammography. Pap smear. colonoscopy. PSA test. All are screening procedures.

All are screening procedures.

Immunotherapy approaches for treating cancer include each of the following except

All of the above are immunotherapy approaches for treating cancer.

Carcinogens can damage DNA by each of the following mechanisms except

All the above are mechanisms by which carcinogens can damage DNA.

Does your explanation suggest how to predict whether AAF is carcinogenic in humans without actually exposing humans to AAF?

Analyzing human liver cells to see if they contain the activating enzyme would indicate whether AAF is likely to be carcinogenic in humans.

How are cancer cells able to evade the immune system and thus able to proliferate seemingly uncontrolled?

Answers need to include having antigenically heterogenous populations; lacking or producing low levels of characteristic surface antigens and thereby replicating below the level of detection; having large numbers of cells can overwhelm the immune system; producting leukotoxins; and hiding (sequestering) in supporting tissues.

Where do Mad and Bub proteins accumulate?

At unattached kinetochores

1) The individual credited for coining the term cancer is A) Paget. B) Hippocrates. C) Folkman. D) Rous. E) Aristotle.

B) Hippocrates.

6) The presence of ________ in the microenvironment of cancer cells acts a potent inhibitor of cell proliferation. A) IL-1 B) TGF-beta C) TNF-alpha D) IL-2 E) INF-gamma

B) TGF-beta

19) A tumor is actively producing both VEGF and FGF, factors associated with angiogenesis. However, no network of blood vessels to the tumor has been established in spite of the fact that blood vessels are nearby. This observation most likely suggests that A) the VEGF and FGF are not functional. B) angiogenesis inhibitors are in greater concentration. C) only one of the molecules is active, not both. D) angiostatin is not produced by the cancer cells. E) the tumor is metastatic.

B) angiogenesis inhibitors are in greater concentration.

4) All of the following are ways cancer cells avoid growth and invasion restriction imposed by the immune system except A) they are heterogeneous groups of cells. B) cancer cells often respond to density-dependent growth factors. C) some cancer cells produce leukotoxins. D) some cancers often "hide" in dense supporting tissue. E) some cancers produce low levels of surface antigens.

B) cancer cells often respond to density-dependent growth factors.

23) Some compounds are themselves not carcinogens, but their metabolic activity on the compound produces intermediates that are carcinogenic. This process is known as A) precarcinogenesis. B) carcinogen activation. C) metabolic carcinogenesis. D) plasminogen activation. E) DNA mutagenesis.

B) carcinogen activation.

39) Changes in an organism that are the result of changes in gene action(s) are known as A) diseases. B) epigenetic. C) silencing. D) micro-RNA mediated. E) all of the above

B) epigenetic.

10) Genes that, when present, trigger the development of cancer are known as A) tumor suppressor genes. B) oncogenes. C) proto-oncogenes. D) apoptosis genes. E) p53.

B) oncogenes.

11) Aneuploidy (the gain or loss of chromsomes) is associated with which protein molecule in cancer cells? A) pRB B) p53 C) Myc D) Blc-2 E) all of the above

B) p53

8) PAHs (polycyclic aromatic hydrocarbons) found in tobacco smoke preferentially bind to regions within the ________ and trigger base substitutions. A) GAL-4 gene B) p53 gene C) DMBA gene D) homeogenes E) viral gene

B) p53 gene

33) In some forms of breast cancer, estrogen is a(n) A) initiator. B) promoter. C) progressor. D) inhibitor. E) mutagen.

B) promoter.

A strain of Drosophila known as dunce produces one-half the amount of cAMP phosphodiesterase than the wild type flies. Using your knowledge of cell signaling based upon cAMP, what effects would you expect in the dunce flies?

Basically, the students need to discuss the fact that cAMP will remain longer in the cell, resulting in prolonged cAMP levels within the cell.

Botulinum toxin blocks neuromuscular transmission, causing paralysis. How does it do this?

Botulinum toxin cleaves the t-SNARE, blocking fusion of the vesicle.

Epstein-Barr virus

Burkitt's lymphoma

17) Which of the following with regard to cancer cells is false ? A) Growth is not regulated by growth factors. B) The cell cycle is disrupted. C) Most cancer cells die in G1 phase. D) Growth is not stopped by high levels of DNA damage. E) The apoptosis pathway is blocked.

C) Most cancer cells die in G1 phase.

22) With regard to cancer cells in the process of metastasis to secondary sites, which of the following statements is not correct? A) If they enter via lymphatics, cancer cells may multiply in regional lymph nodes. B) Many cells from the primary mass may enter circulation. C) The population of cancer cells in the bloodstream is monoclonal. D) Very few cancer cells survive the bloodstream. E) The population of cancer cells is heterogeneous.

C) The population of cancer cells in the bloodstream is monoclonal.

38) During microscopic examination of potential cancer cells, some of the cells are graded as anaplastic. This means they A) divide slowly. B) are easily identified to tissue of origin. C) are poorly differentiated. D) respond well to chemotherapy. E) are not aggressive.

C) are poorly differentiated.

36) The difference between benign and malignant tumors is that A) benign tumors have not lost growth control. B) benign tumors do not stimulate angiogenesis. C) benign tumors have not spread to other sites. D) malignant tumors are adherent. E) benign tumors are cancers, while malignant tumors are not.

C) benign tumors have not spread to other sites.

31) Using polyethylene glycol, a cancer cell and a normal cell are fused. The resulting hybrid behaves like a normal cell. The best reason for this observation is the A) recombination between cancer and normal chromosomes. B) removal of environmental triggers. C) presence of tumor suppressor genes and gene products. D) exposure to polyethylene glycol. E) both choices A and C

C) presence of tumor suppressor genes and gene products.

2) Which of the following statements is true regarding factors associated with the immortalization of cancer cells? A) inhibition of growth B) stimulation of apoptosis C) telomerase activity D) tumor-suppressor activation E) both choices B and D

C) telomerase activity

The region of the centromere contains repeated DNA sequences known as ________.

CEN sequences

Each of the following is involved in DNA replication licensing during S phase except

CENP-A

Which of the following recruits proteins to form a kinetochore at the centromere ?

CENP-A

Each of the following is involved in DNA replication licensing during S phase except

CENP-A.

________ are genetically engineered proteins that allow cytosolic calcium fluxes to be observed by an increase in fluorescence.

Cameleons

Describe the first stage involved in metastasis. Select the two correct statements.

Cancer cells invade surrounding tissues and penetrate through the walls of lymphatic and blood vessels, thereby gaining access to the bloodstream. The first step is facilitated by decreased cell-cell adhesion, increased motility, and secretion of proteases that degrade the extracellular matrix and basal lamina.

Describe the third stage involved in metastasis. Select the two correct statements.

Cancer cells leave the bloodstream and enter particular organs, where they establish new metastatic tumors. During the third step, the sites to which cancer cells tend to metastasize are determined by the location of the first capillary bed encountered as well as organ-specific conditions that influence cancer cell growth.

Describe two pieces of evidence supporting the idea that cancer cells secrete molecules that stimulate angiogenesis. Cancer cells produce and secrete angiogenesis-activating proteins called vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF), which bind to receptor proteins on the surface of endothelial cells. The activated endothelial cells then organize into hollow tubes that develop into new blood vessels. Cancer cells when injected into mice with mutated blood vessels secrete proteins that profiltrate through blood vessel tissue and link up to the mutated blood vessels. Then these proteins produce endothelial cells that replace mutated cells, and so repair blood vessels. After all vessels are repaired new blood vessels start to grow. In a normal tissue cancer cells grow to reach enormous size. As the size increases the amount of blood vessels in the surrounding host tissues increases significantly. When cancer cells are removed after surgical intervention, some blood vessel cells die to reject the total amount of vessels. The only conclusion is that cancer cells produce molecules that activate angiogenesis. When cancer cells are placed in a chamber surrounded by a filter possessing tiny pores that cells cannot pass through, and the chamber is then implanted into animals, new capillaries proliferate in the surrounding host tissue. Since the cancer cells cannot pass through the filter, the most straightforward interpretation is that the cells produce molecules that diffuse through the tiny pores in the filter and activate angiogenesis in the surrounding normal tissue.

Cancer cells produce and secrete angiogenesis-activating proteins called vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF), which bind to receptor proteins on the surface of endothelial cells. The activated endothelial cells then organize into hollow tubes that develop into new blood vessels. When cancer cells are placed in a chamber surrounded by a filter possessing tiny pores that cells cannot pass through, and the chamber is then implanted into animals, new capillaries proliferate in the surrounding host tissue. Since the cancer cells cannot pass through the filter, the most straightforward interpretation is that the cells produce molecules that diffuse through the tiny pores in the filter and activate angiogenesis in the surrounding normal tissue.

Each of the following is involved in regulating mitotic Cdk activity except

Cdk synthesis and degradation

Animal cell centrosome MTOCs contain

Centrioles

After chromsomes condense, the ________________ is the region where the identical DNA molecules are most tightly attached to each other.

Centromere(s)

The ____________ are the organizing centers for microtubules involved in separating chromosomes during mitosis

Centrosome(s)

Different chemotherapeutic drugs can do each of the following except

Chemotherapeutic drugs can do all of the above.

Different chemotherapeutic drugs can do each of the following except inhibit DNA topoisomerases required for DNA replication. disrupt spindle microtubules. inhibit metabolic pathways required for DNA synthesis. chemically cross-link DNA strands. Chemotherapeutic drugs can do all of the above.

Chemotherapeutic drugs can do all of the above.

During interphase, most of the nucleus is filled with a complex of DNA and protein in a dispersed form called ______________

Chromatin

G1 and M, How can you tell where a cell is located ?

Chromosomes are in an extended form during G1, but in a condensed form during most of M phase

G1 and M

Chromosomes are in an extended form during G1, but in a condensed form during most of M phase.

G2 and M

Chromosomes are in an extended form during G2, but in a condensed form during most of M phase.

G2 and M, How can you tell where a cell is located ?

Chromosomes are in an extended form during G2, but in a condensed form during most of M phase.

Phosphorylation of __________ is directly required for chromosome condensation

Condensin

________ nucleotides are common signals in animal cells but not in plant cells.

Cyclic

Which of these is NOT correct?

Cyclic AMP binds to calmodulin.

In most eukaryotes, division of the nucleus is followed by ________, when the rest of the cell divides.

Cytokinesis

7) A cell that has lost its capacity to grow in vitro as a monolayer is now A) benign. B) malignant. C) transformed. D) anchorage independent. E) free ranging.

D) anchorage independent.

21) The correct order of events in metastasis of a cancer is A) invasion → angiogenesis → transport → new site B) transport → invasion → angiogenesis → new site C) transport → angiogenesis → invasion → new site D) angiogenesis → invasion → transport → new site E) angiogenesis → transport → invasion → new site

D) angiogenesis → invasion → transport → new site

25) The branch of medicine that investigates the occurrence and distribution of diseases is A) immunology. B) physiology. C) pathology. D) epidemiology. E) gene therapy.

D) epidemiology.

30) Which of the following is not a category for the gene product for an oncogene? A) growth factor receptor B) nonreceptor protein kinase C) transcription factor D) glycolytic enzyme E) growth factor

D) glycolytic enzyme

24) The promotion phase of carcinogenesis refers to A) enhanced levels or exposures to a carcinogen B) metabolic oxidation by a P450 cytochrome C) normal cell progression to a precancerous cell D) precancerous cell progression to a cancerous cell E) the amount of DNA damage in a cell

D) precancerous cell progression to a cancerous cell

13) A new compound developed in the lab was tested as a DNA mutagen. When the Ames test was performed, the results were numerous bacterial colonies following exposure. This result means A) the chemical is safe. B) the chemical is radioactive. C) the chemical is a carcinogen and a low-level mutagen. D) the chemical is a mutagen and may also be a carcinogen. E) the chemical can be moved to human trials.

D) the chemical is a mutagen and may also be a carcinogen.

G1 and S, How can you tell where a cell is located ?

DNA is being synthesized during S; little or no synthesis occurs during G1

G1 and S

DNA is being synthesized during S; little or no synthesis occurs during G1.

Epigenetic changes in gene expression that can lead to cancer by silencing tumor suppressor genes are mediated by

DNA methylation.

A eukaryotic cell G2-M checkpoint assesses the status of

DNA replication

A eukaryotic cell G2-M checkpoint assesses the status of

DNA replication.

what does DNA replication checkpoint ensure?

DNA synthesis is complete before the cell exit G2 by failing to undergo final dephosphorylation that activates cdk-cylcin complex.

Why does DNA contain thymine over uracil? What effect would the presence of uracil in the DNA have on repair?

Deamination of cytosine results in the formation of uracil. Uracil in DNA is detected by uracil-DNA glycosylase for repair. If DNA normally contained uracil, cytosine deamination could not be detected.

28) The viral oncogene associated with the Rous sarcoma virus is A) RAS. B) p53. C) ERBB-2. D) SIS. E) SRC.

E) SRC.

35) Familial adenomatous polyposis coli (APC) is characterized by a small deletion in chromosome 5. In which cells is this deletion present in affected individuals? A) somatic cells B) germline cells C) colon polyps D) colon epithelial cells E) all cells

E) all cells

37) The normal RB gene functions as A) an activator of transcription. B) a proto-oncogene. C) an activator of translation. D) a cell surface receptor. E) an inhibitor of transcription.

E) an inhibitor of transcription.

32) Most cancers are A) environmentally triggered. B) the result of life style. C) inherited. D) viral infections. E) both choices A and B

E) both choices A and B

15) Telomere integrity in cancer cells is the result of A) natural cell aging. B) active telomerase activity. C) exchange of DNA between chromosomes. D) viral infection. E) both choices B and C

E) both choices B and C

34) Hereditary retinoblastoma is the result of a(n) ________ in the RB gene of chromosome 13 in both homologues. A) insertion B) duplication C) inversion D) point mutation E) deletion

E) deletion

29) Which of the following is not a mechanism whereby proto-oncogenes are converted to oncogenes? A) point mutation B) gene amplification C) translocation D) deletion E) silent mutation

E) silent mutation

A key adhesion molecule is ________, which decreases cell adherence when present in insufficient quantities.

E-cadherin

A student wishes to develop a novel strategy to inhibit cancer metastasis involving the use of gene therapy to introduce a virus with a constitutively expressing gene into tumor cells to enhance cell-cell adhesion. Which of the following molecules should the student focus on to constitutively express through gene therapy?

E-cadherin

The appearance that the spindle and sister chromatids are inactive at metaphase is misleading because

Each sister chromatid is being pulled toward its respective pole

________ and ________ have been demonstrated to trigger DNA mutation associated with particular geographical cancers.

Environmental agents; life style factors

Match the infectious agent with the appropriate cancer type. Drag the appropriate labels to their respective targets.

Epstein-Barr virus = Burkitt's lymphoma hepatitis B virus = liver cancer human papilloma virus = cervical cancer Helicobacter pylori = stomach cancer parasitic flatworms = bladder cancer

True or false? P450 cytochromes is a category into which proteins encoded by oncogenes fit.

FALSE

________ is a new technique that has facilitated cell cycle studies.

Flow cytometry

A toxin that inhibits the production of GTP would interfere with the function of a signal transduction pathway that is initiated by the binding of a signal molecule to _____ receptors.

G-protein-linked

Cell growth primarily during which of the following cell-cycle phases ?

G1

Cells grow primarily during which of the following cell-cycle phases?

G1

Cells that will never divide again are likely to be arrested in this phase.

G1

Cells that will never divide again are likely to be arrested in what phase?

G1

The cell-cycle phase that varies most in duration in various eukaryotic adult cell types is

G1

G1 and G2, How can you tell in where a cell is located ?

G1 has the 2C amount of DNA; G2 has the 4C amount

G1 and G2

G1 has the 2C amount of DNA; G2 has the 4C amount.

Which of the following is eliminated in rapidly dividing embryonic cells that get smaller with each cell division ?

G1 phase

Which of the following is eliminated in rapidly dividing embryonic cells that get smaller with each cell division?

G1 phase

Chromosomes are present as diffuse, extended chromatin in what phase ?

G1, S, G2

Chromosomes are present as diffuse, extended chromatin.

G1, S, G2

Phases that are part of interphase ?

G1, S, G2

This phase is part of interphase.

G1, S, G2

A Cdk protein is present in the cell in what phase ?

G1, S, G2, M

A Cdk protein is present in the cell.

G1, S, G2, M

A cell cycle checkpoint has been identified in this phase

G1, S, G2, M

A cell cycle checkpoint has been identified in this phase.

G1, S, G2, M

In the cell cycle, a mitotic Cdk is present during

G1, S, G2, M

The cell-cycle phase that varies most in duration in various eukaryotic adult cell types is

G1.

The α-subunit of a heterotrimeric G protein is active when bound to ________.

GTP

necessary for the activation of heterotrimeric G proteins

GTP

How does genetic instability arise, and how might you test your hypothesis?

Genetic instability can arise by disruptions in DNA repair mechanisms, defective p53 pathways, disruptions in chromosome sorting during mitosis, and mutations associated with the mitotic spindle checkpoint. Experiments could involve adding specific defects by deletion or adding genes or by exposure to various mutagenic agents.

What is the restriction point influenced by ?

Growth factors, nutrients, cell size, and DNA damage.

In heterotrimeric G proteins, the ________ subunit stimulates adenylyl kinase.

Gα

Name some examples of viruses that can cause cancer.

HPV, Hepatitis B & C, and Epstein-Barr

precursor of diacylglycerol

IP3

Which virus has not been associated with a particular type of cancer?

Influenza virus

In dividing cells, most of the cell's growth occurs during _____________

Interphase

Based on the graph, how long does it take for maximal Ras activation to be achieved?

It takes approximately 1.5−2 min to reach maximal Ras activation GRAPHS MAY VARY

During mitosis, microtubules attach to chromosomes at the ______.

Kinetochore(s)

Mitotic cyclin is at its lowest level in what phase ?

M

Mitotic cyclin is at its lowest level.

M

Sister chromatids separate from each other in what phase ?

M

Sister chromatids separate from each other.

M

The nuclear envelope breaks into fragments in what phase?

M

The nuclear envelope breaks into fragments.

M

The primary cell wall of a plant cell forms in what phase?

M

The primary cell wall of a plant cell forms.

M

Which of the following outcomes would you expect to see if Ras were to acquire a mutation in which its GTPase activity were abolished ?

MAP kinases will be continuously activated, promoting continual and repeating mitotic divisions

The mechanism by which DNA is licensed to replicate only once during each S phase involves

MCM proteins binding only to nonreplicated DNA

How does the APC become inhibited at the spindle assembly checkpoint?

Mad and Bub proteins converted into multicomplex that blocks the Cdc20 protein

Cancer cell aneuploidy (gain or loss of chromosomes) is most likely caused by a defect in

Mad.

Cancer cell aneuploidy (the gain or loss of chromosomes) is most likely caused by a defect in

Mad.

The ____________________ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division.

Mitotic Spindle(s)

Imagine that you are a graduate student working in a cancer lab. You accidentally mix unlabeled tubes of carcinoma cells with tubes of normal epithelial cells. Which of the following is NOT a possible strategy to allow you to distinguish which tubes contain carcinoma cells?

Monitor the rate of cell division.

Why do eukaryotic chromosomes have multiple origins of replication? Design an experiment that allows you to test your hypothesis.

Multiple origin of replication sites allow the DNA to be more efficiently replicated. Theoretically, S phase would be prolonged in those cells replicating DNA with fewer origin sites (those lacking an origin of replication would not be replicated), while a similar DNA strand with additional origins of replication would be replicated more quickly.

________ is the second messenger associated with the regulation of blood pressure.

Nitric oxide

How could you determine which sample contains the cancer cells?

Normal cells: -need anchorage for growth -don't divide more than 50-60 times in culture Cancer Cells: -grow to higher population densities in culture -have mechanisms for replenishing their telomeres in culture -produce tumors being injected into nude mice -grow well in culture

Which of the following occurs during prometaphase (late prophase)?

Nuclear envelope fragmentation

small pieces of DNA synthesized on the lagging strand are called ________.

Okazaki fragments

Describe the second stage involved in metastasis. Select the two correct statements.

Only a tiny fraction of the cancer cells that enter the bloodstream survive the trip and establish successful metastases. During the second step, the cancer cells are transported by the circulatory system throughout the body.

spindle assembly checkpoint

Operates at the metaphase/anaphase transition to check for misaligned chromosomes (the third critical checkpoint).

A way of making multiple copies of a segment of DNA from a single template is known as ________.

PCR (polymerase chain reaction)

What kind of receptor is likely to be involved in responding to bacterial proteins?

Pertussis toxin ADP ribosylates certain G proteins. It would be likely that a neutrophil responds to bacterial proteins through a G protein-linked receptor.

________ produces the second messenger diacylglycerol (DAG).

Phospholipase C

How does the tumor microenvironment influence the growth, invasion, and metastasis of tumor cells? Design an experiment that allows you to test your hypothesis.

Possible examples include angiogenesis triggered by growth factor release, proteases to facilitate invasion of the basal lamina, etc. Possible experiments include removal of the factor to change the microenvironment or additon of the factor to the microenvironment

The generation time for a particular cell type is the time it takes a cell to

Progress through a complete cell cycle

Which of the following correctly orders the stages of mitosis ?

Prophase, prometaphase, metaphse, anaphase, telophase

Children with xeroderma pigmentosum usually cannot carry out excision repair. Why does this makes them so susceptible to developing cancer?

Pyrimidine dimers caused by exposure to sunlight can create mutations that lead to cancer, and one of the main mechanisms for repairing such defects is excision repair.

Main causes of cancer

Radiation, carcinogens, infectious agents, and hereditary

The ________ leads to the release of importin-bound proteins and stimulates microtubule assembly.

Ran-GTP complex

monomeric G protein

Ras

Why does Ras activity decline after a few minutes, even when EGF is still present?

Ras activity gradually decreases due to the action of Ras GAPs, which stimulate Ras to hydrolyze GTP to GDP, inactivating Ras.

Compare and contrast cell signalling via receptor serine/threonine kinases and Ras.

Receptor serine/threonine kinases act through receptor-regulated Smads and the accessory Smad4. Together, they enter the nucleus as a complex following receptor activation. Ras is regulated by GAPs and Sos (guanine-nucleotide exchange factor). This in turn activates a cascade of phosphorylation events, resulting in the activation of transcription factors that mediate gene expression.

The multiple sites of DNA replication along eukaryotic chromosomes are known as

Replicons

The ________ virus in chickens was the first association between viral infection and cancer.

Rous sarcoma

The first demonstration that cancer could be caused by a virus involved

Rous sarcoma virus in chickens.

Genomic DNA is replicated during which of the following cell-cycle phases ?

S

The amount of nuclear DNA in the cell doubles in what phase ?

S

The amount of nuclear DNA in the cell doubles.

S

Figure:

S= DNA replicates G2 = Centrosome replicates M = Mitotic spindle begins to form M = cell divides, forming two daughter cells G1= non dividing cells exit cell cycle, and cell commits to go through cycle

DNA replication produces two identical DNA molecules, called _______________, which separate during mitosis

Sister chromatid(s)

Using specific examples, distinguish between those mutations that are spontaneous and those that are the result of exposure to substances. How might some of the exposures be used in cellular biology?

Spontaneous mutations are those that are intrinsic to the DNA itself and include mismatching due to tautameric shifts, deamination, depurination, and depyrimidation. They occur at a relatively low frequency. Induced mutations are due to exogenous chemicals or radiation. Examples include pyrimidine dimers, frameshift mutations, base analogs, etc. They occur at a relatively high frequency. In cellular biology, ethidium bromide (an intercalating agent) has been used to allow us to visualize nucleic acids in gel electrophoresis, to intentionally induce mutations, and to base analogues in chemotherapy and antiviral treatment.

Why is this test almost useless as a tool for colon cancer screening?

Testing 100,000 people, the 2% false positive rate yields many more incorrect results (2,000) compared to real cancer cases (55).

How is a tumor suppressor gene different from an oncogene?

The absence of a tumor suppressor gene promotes cancer, whereas the presence of an oncogene promotes cancer.

Why do you think beta-blockers are effective in reducing blood pressure?

The binding of epinephrine to beta-adrenergic receptors causes a stimulation of heart function, both in terms of heart rate and with respect to the amount of work done in pumping blood. The effect appears to be mediated by cyclic AMP. When an antagonist such as the beta blocker propranolol is given to patients with hypertension, the cellular response caused by the binding of epinephrine to beta receptors is partially inhibited. Heart function is gradually restored over a period of time, with a corresponding decrease in blood pressure

Which of the following would be expected if the Rb protein were mutated such that it could not be phosphorylated by cyclin dependent kinases ?

The cell will not be able to enter S phase

Using these tools, describe how you could demonstrate that a hormone exerts its effect by (1) causing Ca2+ to enter the cell through channels or (2) releasing Ca2+ from intracellular stores such as the ER.

The chelator could be added to the extracellular medium to reduce the calcium levels outside the cell. Addition of the chelator to the extracellular medium should block the action of the hormone if it depends on calcium influx. If the action of the hormone depends solely on calcium release from intracellular stores, then addition of a calcium ionophore should mimic the action of the hormone. In this case, the ionophore should be effective even when EGTA is added to the extracellular medium to reduce the free calcium ion concentration.

To measure the G2 phase, radioactive thymidine (a DNA precursor) is added to the culture at some time t, and samples of the culture are analyzed autoradiographically for labeled nuclei at regular intervals thereafter. What specific observation would have to be made to assess the length of the G2 phase?

The first appearance of label in prophase nuclei would have to be observed.

You are an epidemiologist/pathologist working in a lab analyzing tissue samples. An oncologist brings two biopsies of two different tumors from the same patient. She would like to know which tumor is more malignant and requires more aggressive and timely treatment. Which of the following morphological features of the biopsies will dictate which tumor is more malignant?

The tumor with a high nucleus-to-cytoplasm ratio should require more aggressive and timely treatment.

What do the experiments with fusion of Sphase cells and G1 cells suggest?

These experiments suggest that molecules in the cytoplasm drive cells from G1 to S or G2 to M

Each of the following is a way cancer cells avoid growth and invasion restriction imposed by the immune system except

They respond to density-dependent growth factors.

________ synthesis is a damage-tolerant mechanism that allows synthesis of a new DNA strand from a damaged template.

Translesion

Many chemicals are more mutagenic after being processed in the liver. True False

True

In the cell cycle, controlled degradation of regulatory proteins occurs via the

Ubiquitin-proteasome pathway

The anti-angiogenic drug Avastin works by binding to and inhibiting the activity of

VEGF.

Consider the mechanism of Botulinum toxin. Is this toxin reversible?

Yes, however the cell must regenerate new t-SNAREs.

The normal RB gene product functions as

a cell-cycle protein.

cyclin-dependent kinases (Cdks)

a regulatory protein that depends upon the presence of cyclin to complete its function, also the phosphorylation of Cdks helps regulation of transition points.

Which of these is NOT an example of the protein product of an oncogene?

a tumor suppressor

What could be an oncogene or a proto-oncogene?

a viral gene that induces the S phase.

Epidemiologists at the CDC in Atlanta, GA, have called you in to investigate an increased incidence of leukemia in a remote region of Africa. Shortly after arriving, an RNA virus was isolated from patients and found to induce leukemia in mice. At this point you don't know the mechanism or viral gene product associated with the development of leukemia. One of your lab assistants has isolated a variant of the virus and reports that this variant is missing a portion (20%) of the genome of the original virus. Furthermore, this variant does not induce leukemia in mice. a) How would you determine which portion of the genome is associated with the development of leukemia? b) How would you determine the viral mechanism and product associated with the development of leukemia?

a) DNA sequence comparisons between the two strains of virus. b) Look for sequences of a known oncogene, or test cells for insertion near or in an proto-oncogene.

Based on your knowledge of cancer and carcinogenesis, address the following: a) What type of mutation would be directly expressed, and therefore dominant, in the development of cancer? Why? b) What type of mutation would be expressed as a recessive trait in the development of cancer? Why? c) Based upon your previous answers, how would you treat these situations using a gene therapy approach?

a) proto-oncogenes b) tumor suppressor genes c) many answers are possible, including using homologous recombination or site-specific deletion in part a and one good copy of the tumor suppressor gene in part b.

Which of the following statements regarding DNA replication is true? A) Bacterial replication is faster than eukaryotic replication. B) DNA replication during embryonic development occurs at a slower rate than in the early stages of neonatal life. C) Early-replicating genes are those that are not actively transcribed. D) The rate of DNA replication is constant at all stages of development in eukaryotes. E) Cyclin-dependent kinases (Cdk) are not involved in the DNA replication process.

a. Bacterial replication is faster than eukaryotic replication.

Which of the following proteins is observed exclusively in association with prokaryotic DNA replication? A) DNA polymerase I B) primase C) helicase D) single-strand binding proteins E) telomerase

a. DNA polymerase I

During the G2 checkpoint in eukaryotic cells, the cell is assessed with regard to A) DNA replication. B) chromosome attachment to the spindle. C) nutrients. D) DNA damage. E) presence of growth factors.

a. DNA replication.

Which of the following statements regarding Fas-mediated programmed cell death is false? A) Fas ligand binding with Fas receptor stimulates a specific G protein. B) Fas ligand and receptor interaction results in the recruitment of adaptor proteins in the target cell. C) Capases are activated in the process. D) The caspase cascade results in the cleavage of the proteins within the target cell. E) It ultimately results in death of the cell.

a. Fas ligand binding with Fas receptor stimulates a specific G protein.

Which of the following signalling proteins is specifically associated with development in animals? A) Hedgehog B) Zbtb7 C) Ryanodine D) calcium-dependent protein phosphorylases E) protein kinase A

a. Hedgehog

You obtain two different preparations of XFF, one of which contains the receptors for XFF. You perform a binding assay and obtain a standard curve. Based upon this data, what value would reflect the affinity of the receptor for the ligand? (Assume a 1 XFF-to-1 receptor interaction.) A) Kd B) Bmax C) Kd - Bmax D) 1/Bmax E) The affinity cannot be detertmined from the information available

a. Kd

Which of the following are associated with the binding of numerous signaling molecules and regulating their responses in multi-enzyme complexes? A) MAP kinase B) 14-3-3 proteins C) growth factor complexes D) alpha-factor E) G-protein activating protein

a. MAP kinase

Kinases are enzymes that A) add phosphate groups. B) do not alter target activity. C) are always inhibitory. D) remove phosphate groups. E) all of the above

a. add phosphate groups.

Which of the following pairings is not correct? A) adenylyl cyclase-ATP B) phospholipase C-diacylglycerol (DAG) C) phospholipase C-inositol triphosphate D) calmodulin-calcium ions

a. adenylyl cyclase-ATP

You have recently identified a molecule that you believe to be a ligand associated with a signal transduction mechanism. All you know about this ligand is that chemically it is hydrophilic. As a result, you expect it to interact with its receptor A) at the outer cell surface. B) within the cytoplasm of the cell. C) within the nucleus of the cell. D) on the cytoplasmic side of the plasma membrane. E) all of the above

a. at the outer cell surface.

Phosphorylation of ________ is required for chromosome condensation. A) condensin B) cyclin C) DNA gyrase D) topoisomerase II E) both choices A and B

a. condensin

Which of the following would be characterized as a juxtacrine signal? A) contact-dependent B) endocrine C) self-responding D) distal neighbors E) both choices B and D

a. contact-dependent

Desensitization of a cell to a ligand may involve all of the following except A) destruction of the ligand. B) a lessened response to the ligand. C) receptor down-regulation. D) receptor-mediated endocytosis. E) lowered affinity of a receptor for the ligand.

a. destruction of the ligand.

Cyclins modulate the progression of cells through the cell cycle by A) directly activating G proteins. B) inducing synthesis of constitutively active forms of growth cell receptors. C) activating protein kinases that are critical regulators of cell division. D) degrading histones. E) increasing the production of DNA polymerases.

a. directly activating G proteins.

Prostaglandins are not A) endocrine hormones. B) important in smooth muscle function. C) paracrine hormones. D) stimulators of inflammation. E) formed from arachidonic acid.

a. endocrine hormones.

An isolate of a mutant bacterium appears to grow more slowly than the population (wild type) from which it was isolated. Further studies showed that the slower growth was due to a markedly reduced DNA polymerase I activity. From this information, one would expect that this organism would also be deficient in the activity of DNA A) excision repair. B) recombination. C) transcription. D) translation. E) unwinding.

a. excision repair.

Kinases and phosphatases are essential in the cell because they A) help turn proteins "on and off" through changes in phosphorylation status. B) are enzymes that destroy damaged proteins. C) sense short poly-A tails in mRNA as a signal to degrade the mRNA. D) destroy second messengers, thereby turning off a signal transduction pathway. E) all of the above

a. help turn proteins "on and off" through changes in phosphorylation status.

The kinase central to second messenger signalling based cAMP is A) protein kinase A. B) ATPase. C) Avastin kinase. D) phosphorylase A. E) RNase PH.

a. protein kinase A.

The multiple sites of DNA replication along eukaryotic chromosomes are known as A) replicons. B) multireplication forks. C) helicase loaders. D) ARS elements. E) none of the above

a. replicons

DNA replication A) requires a type of RNA polymerase. B) is partially regulated by promoter/terminator sites. C) proceeds by making two continuous strands. D) is not edited once polymerization has occurred. E) is conservative.

a. requires a type of RNA polymerase.

Hydrophobic messengers include which of the following? A) retinoids B) cAMP C) pertussis toxin D) calcium ions E) ryanodine

a. retinoids

Which of the following families of proteins is associated with the contractile ring? A) rho B) alpha C) sigma D) kappa E) delta

a. rho

In order to be active, a Cdc-cyclin needs to be A) singly phosphorylated. B) acetylated. C) doubly phosphorylated. D) doubly methylated. E) cleaved by proteases.

a. singly phosphorylated.

Which of the following would be a histological indicator of a pre-cancerous or cancerous state in intestinal epithelial cells?

accumulation of beta-catenin in the nucleus of the colon epithelium

DAG

activates protein kinase C

Cyclins modulate the progression of cells through the cell cycle by directly

activating protein kinases that are critical regulators of cell division.

Mitotic Cdk

active only when bound to mitotic cyclin and the concentration of mitotic cyclin gradually increases through G1, S, G2 until it reaches a crucial threshold at the end of G2

The Gα subunit is responsible for activation of ________.

adenylyl cyclase

Each of the following is true regarding cancer cell metastasis to secondary sites except

all cancer cells circulating in the bloodstream are identical.

Which alteration could cause a cell to proliferate more than it should?

alteration of a protein that normally promotes apoptosis AND alteration of a protein that normally prevents progress through the cell cycle if there is something defective about the cell

Which of the following would NOT be a potential signal the cell would need in order to progress through the G1 checkpoint?

an active p53 protein

A cell that has acquired the capacity to grow suspended in solution is

anchorage-independent.

In actively dividing cancer cells, ________ often results, as three or more poles may be present during mitosis.

aneuploidy

Judah Folkman performed an experiment in which he found that small tumors floating in the anterior chamber of the eye grew little, whereas a similar tumor implanted directly onto the iris grew to thousands of times its original size. These results supported his idea that continued tumor growth is dependent on requirement of tumor growth for

angiogenesis.

A tumor is actively producing both VEGF and FGF, factors that stimulate angiogenesis, but no new network of blood vessels to the tumor has been established in spite of the fact that blood vessels are nearby. This observation suggests that most likely

angiostatin is present in greater concentration.

A type of programmed cell death associated with DNA fragmentation and caspases is known as ________.

apoptosis

Which microtubules shrink during mitosis?

astral and kinetochore microtubules

How does DNA damage arrest the cell cycle at various points?

at late G1,S, and G2: inhibit Cdk-cylcin by p53 being phosphorylated by checkpoint kinases by being phosphorylated by ATM. This prevents it from interacting with Mdm2

Compared to a normal cell, a cancer cell generally divides

at the same rate as a normal cell.

Which enzyme is involved in proofreading during DNA replication? A) 5' to 3' exonuclease B) 3' to 5' exonuclease C) 5' to 3' endonuclease D) 3' to 5' endonuclease E) DNA polymerase

b. 3' to 5' exonuclease

What is the ploidy of an organism that is 7n, where n = 5? A) 5 B) 7 C) 12 D) 35 E) 57

b. 7

Which of the following would not inhibit a cell preparing to undergo mitosis? A) chromosomal abnormalities B) Cdc-activating kinase activity C) Chk1 inhibtion of Cdc25 D) p21 inhibition of G1 E) environmental signals that no new cells are needed

b. Cdc-activating kinase activity

Which of the following proteins is observed exclusively in association with eukaryotic DNA replication? A) DNA polymerase I B) DNA gyrase C) single-strand binding proteins D) DNA ligase E) telomerase

b. DNA gyrase

Killer lymphocytes can elicit self-destruct mechanisms in target cells by interacting with A) Fas ligand. B) Fas receptors. C) Ras ligand. D) adaptor proteins. E) procaspase.

b. Fas receptors.

The phase of the cell cycle that varies most in duration in various cell types is A) M. B) G1. C) S. D) G2. E) both choices A and B

b. G1.

IL-2 is a growth factor that acts on A) embryonic cells. B) T lymphocytes. C) macrophages. D) muscle cells. E) epithelial cells.

b. T lymphocytes.

The phase of the cell cycle associated with the replication of DNA is A) anaphase. B) interphase. C) metaphase. D) prophase. E) telophase.

b. interphase.

Mice lacking the ability to make caspase-9 die as the result of numerous defects. During the necropsy (animal autopsy) of the animal you note that the brains of these mice are A) unregulated growth of the nerve cells. B) lack of apoptosis of some cells. C) overstimulation of G-protein-mediated transduction. D) overproduction of the Etr1 receptor protein. E) all of the above

b. lack of apoptosis of some cells.

It would be useful to determine if the mechanism of action for the XFFXFF receptor is similar to that of estrogen or epinephrine. To test this, you use a nonhydrolyzable analogue of GTP in the reaction mixture. If the mechanism is still similar to that of epinephrine, you would expect the cellular responses would be A) blocked. B) prolonged. C) delayed. D) both choices B and C E) The mechanism cannot be determined.

b. prolonged.

Ultraviolet (UV) light-treated bacteria would most likely have DNA damage in the form of A) analog incorporation. B) pyrimidine dimer formation. C) intercalation of the bases. D) direct transition of the bases. E) deamination.

b. pyrimidine dimer formation.

All of the following are associated with replicons except A) origin of replication. B) single-strand binding proteins. C) initiator proteins. D) minichromosome maintenance proteins. E) helicase loaders.

b. single-strand binding proteins.

DNA repair in eukaryotes that facilitates replication in regions of thymine dimers is mediated by a unique DNA polymerase A) α. B) η. C) β. D) σ. E) δ.

b. η.

parasitic flatworms

bladder cancer

In a cell with a diploid number of 12, how many chromatids are present at prophase of mitosis? A) 6 B) 12 C) 24 D) 48 E) none of the above

c. 24

Using polyethylene glycol (PEG), early G1 phase cells were fused with S phase cells. Of the following events, which would you expect to be induced in the G1 cells as a result of the fusion? A) cytokinesis B) condensation of chromosomes C) DNA replication D) mitosis E) spindle fiber formation

c. DNA replication

Ras is to Raf, as MEK is to A) Ras. B) tyrosine. C) MAPK. D) Cdc. E) cell growth.

c. MAPK.

Which of the following statements is false with regard to G-protein coupled receptors (GPCRs)? A) GPCRs can interact with specific receptor interacting proteins to modify ligand affinity. B) Adenylate cyclase is activated. C) Phosphodiesterase creates v cAMP molecules in response to moderate cAMP levels. D) Protein Kinase A is activated by cAMP. E) cAMP signals for its own degradation indirectly.

c. Phosphodiesterase creates v cAMP molecules in response to moderate cAMP levels.

G protein-adenyl cyclase activity has been shown, in some cases, to be associated with certain diseases. In the case of cholera, which of the following is not correct? A) Vibrio cholera bacteria colonize the gut. B) Cholera toxin is secreted by Vibrio cholera bacteria. C) The cholera toxin causes the cells of the gut to take in salts and fluids. D) Cholera toxin alters Gs so that it no longer hydrolyzes GTP. E) The toxin, by altering Gs, keeps intracellular cAMP levels high and doesn't allow them to decrease.

c. The cholera toxin causes the cells of the gut to take in salts and fluids.

Which of the following statements regarding the Ras protein is false? A) Ras is monomeric. B) It is regulated by GTPase activating proteins. C) The ligands are largely steroid hormones. D) It is regulated by Sos, a guanine nucleotide exchange factor. E) Ras activates a cascade of phosphorylation events.

c. The ligands are largely steroid hormones.

With regard to hormones, responses occurring over the shortest distance would be classified as A) paracrine. B) endocrine. C) autocrine. D) juxtacrine. E) All of the above choices work over similar distances.

c. autocrine.

You are testing a drug that might be marketed as an anti-inflammatory agent. It would be a good choice if it possessed which of the following responses? A) stimulates the release of prostaglandins B) blocks adenylate cyclase activity C) blocks an enzyme associated with arachidonic acid production D) stimulates the activation of platelets E) all of the above

c. blocks an enzyme associated with arachidonic acid production

The protein(s) that facilitate the unfolding of chromatin fibers ahead of the replication fork is (are) A) helicase. B) scaffold proteins. C) chromatin remodeling proteins. D) replisomal proteins. E) both choices A and B

c. chromatin remodeling proteins.

To have a hormone receptor system that is responsive to changes in hormone concentration, it is useful if the concentration of the hormone is A) always more than 10 times the Kd. B) never more than 10 times the Kd. C) far below the Kd before the stimulation of hormone secretion. D) far above the Kd before the stimulation of hormone secretion. E) always constant.

c. far below the Kd before the stimulation of hormone secretion.

A developing organism's failure to produce muscle tissue is most likely due to A) underdevelopment of the ectoderm. B) underdevelopment of the endoderm. C) fibroblast growth factor receptor mutations. D) adenylate cyclase mutations. E) missing chromosomes

c. fibroblast growth factor receptor mutations.

You add a large amount of XFF to cultured liver cells. Which of the following might you observe if XFF can bind to human epinephrine receptors? A) increased cell division B) decreased protein synthesis C) glycogen breakdown D) glucose-6-phosphate polymerization E) all of the above

c. glycogen breakdown

The proteins most actively synthesized during the S phase of the cell cycle are A) DNA polymerases. B) rRNA proteins. C) histones. D) single-strand binding proteins. E) cyclins.

c. histones.

In designing a new drug that may interfere with G-protein coupled receptor interacting protein functions, one possible target for drug action is not A) altering ligand affinity for the receptor. B) promoting close association with other signal proteins. C) modifying epinephrine production. D) promoting receptor dimerization. E) controlling receptor localization in the membrane.

c. modifying epinephrine production.

After determining which preparation contained the XFF receptor, you wish to determine the properties of the ligand receptor. Using a radioactive XFF, you wish to determine if the properties are similar to that of epinephrine and the epinephrine receptor. If so, you expect to find the radioactive XFF A) within the cell. B) associated with the ER. C) on the cell surface. D) associated with mitochondria. E) in the nucleus.

c. on the cell surface.

Which hormone is not an amino acid derivative? A) histamine B) norepinephrine C) prostaglandin D) epinephrine E) thyroxine

c. prostaglandin

DNA replication is A) conservative. B) dispersive. C) semiconservative. D) irregular. E) none of the above

c. semiconservative.

In the cell cycle, controlled degradation of regulatory proteins occurs via the A) P450 - protease pathway. B) cyclin proteolysis pathway. C) ubiquitin-proteosome pathway. D) kinase inhibition pathway. E) none of the above

c. ubiquitin-proteosome pathway.

In animal eggs, once fertilization occurs, ________ are the second messengers that trigger egg activation.

calcium ions

second messenger associated with prevention of penetration of an animal sperm cells

calcium ions

Which of these is activated by calcium ions?

calmodulin

protein that, when bound with calcium, can be second messenger

calmodulin

calcium

can bind calmodulin

The most frequent category of cancer is

carcinoma

________ are cancers that originate in epithelial cells and comprise 90% of all cancers.

carcinomas

The key mediators of apoptosis are the ________.

caspases

adenylate cyclase

catalyzes formation of cAMP from ATP

phospholipase C

catalyzes formation of second messenger diacylgycerol (DAG)

p53-po4 accumulation allows what two events

cell arrest and cell death by activating transcriptional factors on DNA after binding resulting in specific genes like p21 and PUMA, alo activates enzymes for DNA repair

What is G2-M transition influenced by?

cell size, DNA damage, DNA replication

Animal cell centrosome MTOCs contain

centrioles.

2. After chromosomes condense, the _____________ is the region where the identical DNA molecules are most tightly attached to each other.

centromere(s)

The _________ are the organizing centers for microtubules involved in separating chromosomes during mitosis.

centrosome(s)

human papilloma virus

cervical cancer

spindle assembly checkpoint

check for chromosome attachment to spindle by unattched spindle producing wait signal that inhibits APC which inhibits destruction of cohesion that holds the chromatids together.

During interphase, most of the nucleus is filled with a complex of DNA and protein in a dispersed form called __________

chromatin.

What is the Metaphase-anaphase transition influenced by?

chromosome attachments to spindle

Which protein holds the sister chromatids together?

cohesions

ligase

covalently links breaks in sugar-phosphate backbone

Oncogenes encode proteins in each of the following categories except

cytochrome P450 enzymes.

In most eukaryotes, division of the nucleus is followed by ____________, when the rest of the cell divides.

cytokinesis

During metaphase of mitosis, how many telomeres are present in a cell in which 2n = 12? A) 6 B) 12 C) 24 D) 48 E) 1200

d. 48

A population of T cells has been stimulated to proliferate in response to a particular antigen. A sample of 1000 cells is examined microscopically, revealing that 200 of these cells are in the various stages of mitosis. Of the remaining 800 in interphase, 400 have x amount of DNA, 250 have 2x, and the remaining 150 have amounts somewhere between x and 2x. Additional analysis reveals that the G2 phase of the cell cycle lasts 2 hours. What is the total length of the cell cycle? A) 2.5 hours B) 4 hours C) 6.4 hours D) 8 hours E) 13.3 hours

d. 8 hours

All of the following participate in apoptosis except A) caspases. B) death-promoting proteins. C) mitochondria. D) Bcl-2. E) calcium ions.

d. Bcl-2.

IP3 receptors are associated with A) plasma membranes. B) intracellular membranes. C) mitochondrial membranes. D) ER membranes. E) lysosomes.

d. ER membranes

Which of the following is not a receptor tyrosine kinase? A) EGF B) PDGF C) TGF D) FGF

d. FGF

A particular strain of yeast produces strains with a mutant cdc2 gene, resulting in little to no production of the Cdc2 protein kinase. As a result, one would expect that these cells would A) not enter M phase. B) not have the nuclear envelope disperse. C) lack chromosome condensation. D) all of the above E) none of the above

d. all of the above

Which of the following ligands would not have an intracellular receptor? A) cortisol B) retinoic acid C) thyroxine D) epinephrine E) progesterone

d. epinephrine

All of the following are second messengers, except A) cyclic adenosine monophosphate. B) inositol trisphosphate. C) diacylglycerol. D) epinephrine. E) calcium ions.

d. epinephrine.

A NASA probe returned samples of rocks from the surface of Mars. From these rocks, a prokaryotic organism was isolated and remained viable under conditions similar to that of Mars. The organisms are capable of dividing to replicate themselves. In order to determine whether the DNA replication of these organisms was semiconservative, an experiment using N15/N14 (similar to that of Mendelson and Stahl) was performed. If the method of DNA replication were conservative, after one generation one would expect to see A) all of the DNA in the heavy (N15) band. B) all of the DNA in the light (N14) band. C) all of the DNA at a point midway between the heavy and light bands. D) half of the DNA in the light band, the other half in the heavy band. E) none of the above

d. half of the DNA in the light band, the other half in the heavy band.

The longest phase of the cell cycle is A) metaphase. B) prophase. C) telophase. D) interphase. E) anaphase.

d. interphase.

MAPKs are activated by A) methylation. B) microtubules. C) membranes. D) mitogens. E) methionine.

d. mitogens.

Phosphatases are enzymes that A) add phosphate groups. B) are always inhibitory. C) do not alter target activity. D) remove phosphate groups. E) all of the above

d. remove phosphate groups.

Children with hereditary retinoblastoma inherit a chromosome 13 from one parent that has which defect in the RB gene?

deletion

Children with hereditary retinoblastoma inherit a chromosome 13 from one parent that has which of the following defects in the RB gene?

deletion

DNA glycosylase can repair this damage

demination

Each of the following can contribute to proliferation of cancer cells except

density-dependent inhibition of growth.

caused by spontaneous hydrolysis of a glycosidic bond

depurination

occurs with G but not C

depurination

Each of the following is true about anaphase except

during anaphase B, the spindle poles are pushed further apart as interpolar microtubules lengthen. during anaphase A, each chromosome is pulled to its respective pole as its kinetochore microtubules shorten. anaphase is the shortest stage of the mitosis. anaphase B may be coincident with or follow anaphase A, depending on the cell type.

Blood pressure is regulated by the second messenger A) cAMP. B) Ca2+. C) IP3. D) CO. E) NO.

e. NO.

All of the following are second messengers except A) calcium ions. B) IP3. C) DAG. D) cameleons. E) PDGF.

e. PDGF

The phase of the cell cycle associated with the doubling of the amount of DNA in the cell is A) G0. B) G1. C) G2. D) M. E) S.

e. S

) When nitric oxide is used in the dilation of smooth muscle cells, which of the following would interfere with the relaxation of the smooth muscle cells? Inhibitors of A) calcium release by the ER. B) nitric oxide. C) guanylyl cyclase. D) calmodulin. E) all of the above

e. all of the above

In the cell cycle, a mitotic Cdk is present during A) G1. B) G2. C) M. D) S. E) all of the above

e. all of the above

Which of the following is not a plant hormone? A) brassinosteroids B) ethylene C) abscisic acid D) auxin E) allomone

e. allomone

Synthetic compounds that inhibit receptors by preventing the natural messenger from binding are known as A) agonists. B) receptor upregulators. C) specific proteoglycans. D) syndecans. E) antagonists.

e. antagonists

You wish to determine if cytosolic calcium fluxes are associated with signal transduction in a particular cell type. One means of observing the calcium fluxes would be to utilize A) caspases. B) cytochrome c. C) nitric oxide. D) radioactive cAMP. E) cameleons.

e. cameleons.

Which of the following statements concerning the properties of ligands for intracellular receptor systems is correct? A) Steroids are produced from cholesterol. B) Changes in the composition of your diet can affect the concentration of some of these ligands in your body. C) Some ligands are bound to specific proteins when carried in the blood. D) both choices A and C E) choices A, B, and C

e. choices A, B, and C

Which of the following eukaryotic DNA polymerases replicates mitochondrial DNA? A) alpha B) beta C) delta D) epsilon E) gamma

e. gamma

A mutant strain of yeast possesses a mutation in the nda2 gene, resulting in no production of α1 tubulin. As a result, these cells would most likely A) not duplicate their chromosomes. B) not enter M phase. C) not enter S phase. D) keep the nuclear membrane intact. E) have little or no spindle formation.

e. have little or no spindle formation.

If one homogenizes liver cells, separates the membranes from the cytoplasm, and then adds epinephrine to only the cytoplasmic portion, A) cAMP will be produced. B) G-proteins will be activated. C) adenylyl cyclase will be activated. D) calcium ions will be released. E) none of the above

e. none of the above

All of the following circular DNAs exhibit theta replication except A) bacteria. B) mitochondria. C) chloroplasts. D) plasmids. E) protists.

e. protists.

You argue with one of your fellow students that other features of the protein suggest that the protein is much like EGF. To discredit this, you would show the data obtained with A) radioactive XFF. B) binding assay. C) use of nonhydrolyzable GTP analogues. D) amino acid phosphorylation. E) tyrosine kinase inhibition studies.

e. tyrosine kinase inhibition studies.

DNA polymerase III

elongates DNA strand

cdc2

encodes a protein kinase, , whose activity is needed for the G2 to M transition

hormones acting over long distances

endocrine hormones

The branch of medicine that investigates the frequency and distribution of human diseases is

epidemiology.

An ________ is the result of an alteration of gene expression rather than a mutation of a gene.

epigenetic change

Changes in gene action that are often associated with cancer cells are known as ________ changes.

epigentic

Organ transplant patients often develop cancers at rates higher than normal. This observation supports the idea that cancer formation is dependent on

evasion of immune surveillance.

heterokaryon

form a cell with two nuclei

Each of the following involves apoptosis except

generating a cancerous tumor.

cAMP

glucose mobilization

MCdk

halfway through mitosis, cyclin is abruptly degraded

Each of the following is a mechanism by which proto-oncogenes are converted to oncogenes except

histone methylation

What mechanism does not occur when proto-oncogenes are converted to oncogenes?

histone methylation

Each of the following is a mechanism by which proto-oncogenes are converted to oncogenes except

histone methylation.

Which of the following viruses has not been associated with a particular type of cancer?

influenza virus

pertussis toxin

inhibition of Gi

Which of the following would be a reasonable therapeutic strategy to inhibit cancer metastasis?

inhibition of VEGF/FGF secretion

What is another likely role of the SNARE mechanism of vesicle fusion, in addition to secretion of material?

insertion of membrane proteins into the plasma membrane

Dividing adult eukaryotic cells spend most of their time in which of the following?

interphase

4. In dividing cells, most of the cell's growth occurs during _______________

interphase.

________ is the direct migration and penetration of cancer cells into neighboring tissues.

invasion

Analysis of chromosomes in metaphase of mitosis is known as ________ .

karyotyping

Each of the following would inhibit cell progression through the cell cycle except

kinase phosphorylation of mitotic Cdk.

Proteins bound to CEN sequences form a complex known as the ________.

kinetochore

3. During mitosis, microtubules attach to chromosomes at the _________________

kinetochore(s).

A ________ is a cancer of blood cells in which the cells proliferate in the bloodstream.

leukemia

ATR

like ATM but for single stranded breaks instead of double stranded DNA breaks

hepatitis B virus

liver cancer

E-cadherin

low in invasive cells

Cancer cell aneuploidy (the gain or loss of chromosomes) is most likely caused by a defect in

mad

MDM2

marks p53 for destruction by ubiquitin

The enzyme ________ breaks down the extracellular matrix to facilitate angiogenesis.

matrix metalloproteinase

Overexpression of ________ lead to the development of cancer in mice, and variations in their structure or amounts have been documented in various types of cancer cells.

micro-RNAs

The type of DNA repair that fixes mistakes in nucleotide incorporation is known as ________ repair.

mismatch

5. The ____________ is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division.

mitotic spindle(s)

Each of the following is true with regard to cancer cells except

most cancer cells age and die after 50 divisions.

gyrase

nicks DNA ahead of replication fork to relax supercoiling in the DNA

The ________ pathway uses a set of proteins that bind to ends of two broken DNA fragments and join them together.

nonhomologous end-joining

Which of the following occurs during prometaphase (late prophase)?

nuclear envelope fragmentation

Fusion of a cancer cell and a normal cell using polyethylene glycol yields a hybrid cell that behaves like a normal cell because

of the presence of normal cell tumor suppressor genes and gene products in the hybrid cell.

v-myc

oncogene

v-ras

oncogene

v-src

oncogene

The expression of which genes contributes to development of cancer?

oncogenes

The expression of which of the following contributes to development of cancer?

oncogenes

IP3

opens calcium channels

cGMP

opens sensory-associated ion channels

Polycyclic aromatic hydrocarbons in tobacco smoke are potent carcinogens because they preferentially bind to, and trigger base substitutions, in the

p53 gene.

During the cell cycle, MPF activity

peaks in M and decrease in M.

A physician using a microscope to examine suspect cells in biopsy tissue would expect to find each of the following characteristics in metastatic cancer cells except

perfectly spherical nuclei.

Activated CDK-cyclin complex

phosphorylates lamin protein to aid in breakdown of lamina proteins and nuclear envelope

Increased ________ concentrations degrade the basal lamina and extracellular matrix and activate matrix metalloproteinases.

plasmin

Name the mechanisms where proto-oncogenes are converted to oncogenes.

point mutation, gene amplification, deletion, and translocation

Telomerases are important in the replication of linear chromosomes because there is no ________ at the ends of the lagging strands.

primer

helicase

primer removal and replacement

Chronic inflammation caused by infectious agents can increase the chance of cancer because immune cells fighting the infection

produce mutagenic oxygen-free radicals.

The generation time for a particular cell type is the time it takes a cell to

progress through a complete cell cycle.

Chromosome condensation indicates a cell has entered

prometaphase.

In some forms of breast cancer, estrogen is a(n)

promoter

In some forms of breast cancer, estrogen is a(n)

promoter.

MPF

promotes the entrance into mitosis (the M phase) from the G2 phase by phosphorylating multiple proteins needed during mitosis.

Which of the following correctly orders the stages of mitosis?

prophase - prometaphase - metaphase - anaphase - telophase

ATM

protein that phosphorylates checkpoint kinases

Cdk4

proto-oncogene

MYC

proto-oncogene

erbB

proto-oncogene

UV light generates which of the following as a "signature" mutation in a gene?

pyrimidine dimer formation

induced by ultraviolet light

pyrimidine dimer formation

EGF (epidermal growth factor) activates cell division by binding ________.

receptor tyrosine kinases

Most hereditary forms of breast and ovarian cancer arise in women who inherit a mutant copy of either the BRCA1 or BRCA2 gene, each of which encodes a protein involved directly in

repairing DNA double-strand breaks.

Most hereditary forms of breast and ovarian cancer arise in women who inherit a mutant copy of either the BRCA1 or BRCA2 gene, each of which encodes a proteins involved directly in

repairing DNA double-strand breaks.

DNA replication of linear chromosomes has multiple sites known as ________.

replicons

The multiple sites of DNA replication along eukaryotic chromosomes are known as

replicons

Each of the following occurs during apoptosis of a cell except

rupture of the cell, releasing cytoplasmic contents.

In situations where signaling pathway components need to be "fixed" in a particular position within the cell (e.g., in the yeast mating pathway), they are associated with ________.

scaffolding proteins.

The ultimate, coordinated response of cells to a vast array of signals from the environment is known as ________.

signal integration

Mitotic Cdk-cyclin is active when it is

singly phosphorylated.

1. DNA replication produces two identical DNA molecules, called _________ which separate during mitosis.

sister chromatid(s),

In the Ames Test, the appearance of his+ revertants in the presence of a non-mutagenic control compound indicates that _______. liver extract increases the potency of some mutagens there is some low-level contamination in most experiments some of the reversion mutations are not caused by the mutagen being tested the growth medium contains factors that are mildly mutagenic

some of the reversion mutations are not caused by the mutagen being tested

The viral oncogene associated with the Rous sarcoma virus is the

src gene.

Helicobacter pylori

stomach cancer

Which of the following is NOT a characteristic of a cell undergoing apoptosis?

swelling and cell rupture

primase

synthesizes RNA primers for DNA synthesis

Some cancer cells produce the enzyme ________, which avoids stimulating apoptosis based on the number of cell divisions.

telomerase

At least one aspect of aging has been determined to be the shortening of the ________ with each successive round of cell division.

telomeres

The purpose of the Ames Test is to _______. determine whether histidine has mutagenic effects in S. typhimurium test the mutagenic effects of chemicals study how the liver affects potential mutagens determine whether Salmonella typhimurium his- mutants can revert to his+

test the mutagenic effects of chemicals

primary signal associated with platelet activation

thrombin

A mitotic Cdk-cyclin complex __________.

triggers entry into mitosis

BRCA-1

tumor suppressor gene

p53

tumor suppressor gene

PUMA

turned on by p53, promotes apoptosis by binding to and inactivating a normally occurring inhibitor of apoptosis known as Bcl-2

p21 gene

turned on by p53; the products of this gene halt the cell cycle by binding to cdk's which allows time for DNA repair by inhibiting ckd-cyclin complex

DNA polymerase I

unwinds double-stranded DNA

What causes Mad and Bub to be no longer converted and stop inhibiting Cdc20 which in turn stops inhibiting APC

when all chromosomes are attached to spindles