Deck 21: The Genetic Basis Of Cancer

Question 1

Programmed cell death is called

A) cell lysis
B) apoptosis
C) cell popping
D) hemolysis
E) None of these are correct.

Answer 1

B

Question 2

What classifies a tumor as being malignant?

A) When cells do not invade surrounding tissue
B) When the tumor is under 10mm in diameter
C) When cells detach from the tumor and invade surrounding tissue
D) When the tumor is over 10mm in diameter
E) None of these are correct.

Answer 2

C

Question 3

Which of the following is not true regarding cancer?

A) It is a group of diseases.
B) Every type of cancer can be stopped with current medical treatments.
C) Some cancers grow aggressively while others grow slowly.
D) Cancer can originate in different tissues of the body.
E) All statements are true.

Answer 3

B

Question 4

Which statement is not true about checkpoints in the cell cycle?

A) They can halt cell cycle progression in response to environmental influences.
B) They are a complex machinery that uses cyclins and cyclin-dependent kinases to regulate cell cycling.
C) They occur only in the middle of the G? phase of the cell cycle.
D) All of these are correct.
E) None of these are correct.

Question 5

Which of the following causes cancer?

A) Mutations in genes that control cell growth and division
B) Mutations in genes that control pigmentation in skin
C) Mutations in genes that control the differentiation of cell types
D) All of these are correct.
E) None of these are correct.

Question 6

CDKs

A) phosphorylate cell cycle regulating proteins independently.
B) are inactivated by binding to a cyclin.
C) by controlling the progression through cell cycle checkpoints.
D) All of these are correct.
E) None of these are correct.

Question 7

The START checkpoint

A) controls entry into the S phase.
B) controls exit from the S phase.
C) controls entry into the G2 phase.
D) only occurs in yeast cells.
E) functions at mitosis.

Question 8

Which of the following cancers is most prevalent in the United States?

A) Breast cancer
B) Prostate cancer
C) Lung cancer
D) Pancreatic cancer
E) Leukemia

Question 9

What are cellular homologues of viral oncogenes called?

A) Non-cellular oncogenes
B) Adaptive oncogenes
C) Proto-oncogenes
D) Pre-oncogenes
E) Post-oncogenes

Question 10

Which of the following is the abiding characteristic of all cancer cells?

A) Caused by the presence of radiation
B) Uncontrolled growth
C) Multinucleated
D) Form a monolayer in culture
E) All of these are correct.

Question 11

Which property is not exhibited by tumor-causing retroviruses?

A) It contains a gene encoding a reverse transcriptase.
B) The gag gene encodes a viral surface protein.
C) The v-onc gene causes the tumor.
D) The viral oncogene usually has a cellular homolog.
E) The env gene encodes the capsid protein of the virion.

Question 12

Which of the following genes would be considered an oncogene?

A) Gag
B) Env
C) V-src
D) Gag and Env
E) All of these are correct.

Question 13

Which of the following properties is not characteristic of a malignant cell?

A) It no longer undergoes cell cycle regulation and growth arrest.
B) It has undergone mutations in a c-onc and in other genes.
C) It cannot leave its site of growth in the tumor.
D) It may have undergone a chromosome rearrangement.
E) All of these are correct.

Question 14

Mutations in _______ can actively promote cell division.

A) Tumor suppressor genes
B) Oncogenes
C) Operator genes
D) Promoter genes
E) Silencer genes

Question 15

Which enzyme family plays a crucial role in apoptosis?

A) Caspases
B) Lactases
C) Maltases
D) Kinases
E) Polymerases

Question 16

Mutations in __________ lead to a failure to repress cell division.

A) Tumor suppressor genes
B) Oncogenes
C) Operator genes
D) Promoter genes
E) Silencer genes

Question 17

The genetic basis for cancer was suspected long before the scientific evidence was uncovered.The suspicion was due to

A) the cancerous property of tumor cells is clonally inherited.
B) tumors can be induced by mutagenic chemicals and ionizing radiation.
C) some forms of cancers tend to run in families.
D) chromosomal arrangements were often associated with certain kinds of tumors.
E) All of these are correct.

Question 18

An agent that can irreversibly transform normal cells into cancerous cells is most correctly known as

A) tetragen
B) aneugen
C) mutagen
D) carcinogen
E) None of these are correct.

Question 19

Of the four genes found in the Rous sarcoma virus,which provides tumor suppression ability?

A) Gag
B) Env
C) Pol
D) V-src
E) Gag and Env

Question 20

Which group of genes was first discovered in RNA virus genomes and is known to induce tumors in vertebrate hosts?

A) Tumor suppressor genes
B) Oncogenes
C) Operator genes
D) Promoter genes
E) Silencer genes

Question 21

How does p53 respond to cell stress?
1)The level of p53 increases dramatically.
2)p53 stimulates the transcription of genes whose products arrest the cell cycle.
3)p53 activates another set of genes whose products ultimately cause the damaged cell to die.

A) 1
B) 2
C) 3
D) 1 and 2
E) All of these

Question 22

Tumor suppressor genes

A) were discovered by studies of rare cancers exhibiting a dominant inheritance pattern.
B) were suggested by Alfred Knudson's findings in his 1971 study of retinoblastoma.
C) function in more than one cellular process.
D) of particular classes function by binding to and inhibiting the activity of transcription factors controlling cell cycle progression.
E) All of these

Question 23

Which of the following is a key step in carcinogenesis?

A) Loss of p53 function
B) Gain of pRB function
C) Gain of p53 function
D) Loss of p53 function and Gain of pRB function
E) All of these

Question 24

How do cancers develop?

A) Through the activation of a singular proto-oncogene
B) Through the activation of a singular tumor suppressor gene
C) Through the accumulation of somatic mutations in proto-oncogenes and tumor suppressor genes.
D) Through the inactivation of a singular tumor suppressor gene
E) Through the inactivation of a singular proto-oncogene

Question 25

Which of the following genes have been implicated in hereditary forms of breast cancer?

A) BRCA1
B) BRCA2
C) RB
D) phMSH2
E) BRCA1 and BRCA2

Question 26

Burkitts lymphoma and chronic myelogenous leukemia are associated with which of the following?

A) Lack of tumor suppressor genes
B) Formation of thymidine dimers due to UV light exposure
C) Mutations induced by exposure to carcinogens in cigarette smoke
D) Reciprocal translocations on chromosomes
E) None of these

Question 27

Mutations in HPC1

A) cause glioblastomas in the brain.
B) lead to prostate cancer when mutations in TP53, RB, and NF2 also occur.
C) is the gene for the inherited form of prostate cancer.
D) require mutations in several other tumor suppressor genes to cause polyposis carcinomas.
E) None of these

Question 28

Why do v-oncs cause cancer whereas normal c-oncs do not?

A) More than one v-onc occurs in the tumor cell.
B) C-oncs are never expressed except when infected by a retrovirus.
C) Expression of both the v-onc and the c-onc is enough to cause transformation.
D) The v-oncs are expressed at much higher levels from the strong retroviral promoter than are c-oncs.
E) All of these are correct.

Question 29

Which of the following is true regarding the RB gene in relation to cancer and the cell cycle?
1)In many types of cancer both copies of the RB gene have been inactivated.
2)Inactivation of both copies of the RB gene impair the ability of the RB protein to bind E2F transcription factors.
3)pRB is phosphorylated through the action of cyclin-dependent kinases.

A) 1
B) 2
C) 3
D) 1 and 2
E) All of these

Question 30

What type of mutations are typically found in the DBD of p53?

A) Recessive loss of function mutations
B) Recessive gain of function mutations
C) Dominant loss of function mutations
D) Dominant gain of function mutations
E) None of these

Question 31

Which of the following is not a tumor suppressor gene?

A) p16
B) c-myc
C) RB
D) NF2
E) TP53

Question 32

Which of the following was found to be a difference between v-src and c-src?

A) C-src contained eleven introns whereas v-src had none.
B) V-src contained eleven introns whereas c-src had none.
C) C-src caused the formation of tumors in mice, whereas v-src caused tumor formation in chickens.
D) V-src caused the formation of tumors in mice, whereas c-src caused tumor formation in chickens.
E) None of these are correct.

Question 33

Where are most of the mutations that inactivate p53 located?

A) N-terminal transcription-activation domain
B) Central DNA-binding core domain
C) C-terminal homo-oligomerization domain
D) D-terminal binding domain
E) None of these

Question 34

Which statement is not true about the tumor suppressor gene pAPC?

A) Is involved in adenomatous polyposis coli, an inherited condition leading to colorectal cancer
B) Only regulates cell proliferation
C) Causes cancer by binding b-catenin, a regulator of apoptosis
D) Causes cancer in a heritable manner only when the FAP gene is mutated as well.
E) None of these

Question 35

Which of the following is true regarding tumor-inducing retroviruses?

A) Retroviruses are double-stranded DNA viruses.
B) The enzyme reverse transcriptase is essential for transcribing the viral DNA into RNA.
C) Cancer-causing genes encoded by the viral genome are called proto-oncogenes.
D) Each type of viral gene that can cause cancer can potentially regulate the expression of cellular genes.
E) Viral genes that can cause cancer are different from other viral genes because they possess introns.

Question 36

Mutations in which a single mutant allele is dominant in its ability to induce cancer are known as

A) recessive activators.
B) dominant activators.
C) heterozygous activators.
D) homozygous activators.
E) penetrant activators.

Question 37

Which of the following is not a component of Knudson's "two hit" hypothesis?

A) In the inherited cases of retinoblastoma, one of the inactivating mutations has been transmitted through the germ line.
B) Two mutational "hits" are required to knock out a gene that normally functions to suppress tumor formation.
C) A cancer develops only if a second mutation occurs in the somatic cells and if this mutation knocks out the function of the wild-type allele of the tumor suppressor gene.
D) All of these are true.
E) None of these are true.

Question 38

Which of the following is the best example of a tumor-suppressor gene?

A) The RB gene involved in retinoblastoma
B) Philadelphia chromosome in chronic myelogenous leukemia
C) C- ras involved in human bladder cancer
D) C-myc involved in Burkitt's lymphoma.
E) Platelet-derived growth factor (PDGF)

Question 39

Weinberg was the first to identify a link between a c-onc and cancer by

A) using a transfection test with liver DNA that transformed normal cells to hepatomas.
B) cloning a DNA fragment from human colon cancer and showing that it could transform normal cells to malignant cells.
C) serially transfecting DNA from bladder cells first into nontransformed cells and then into transformed cells.
D) cloning the transforming DNA fragment from the transformed cells and showing it transformed normal cells.
E) None of these

Question 40

The normal alleles of genes such as c-ras and c-myc produce proteins that regulate the cell cycle.When these genes are overexpressed,or when they produce proteins that function as dominant activators,the cell is

A) cancerous.
B) pre-disposed to become cancerous.
C) immune from becoming cancerous.
D) cancerous and Pre-disposed to become cancerous.
E) None of these

Question 41

How does the inactivation of mutations in the APC gene initiate tumor formation?

A) By causing the development of abnormal tissues within the intestinal epithelium
B) By causing the development of abnormal tissues within the breast tissue
C) By causing the development of abnormal tissues within the connective tissue
D) By causing the development of abnormal tissues within the nervous tissue
E) By causing the development of abnormal tissues within the muscular tissue

Question 42

Which of the following is not a hallmark of the malignant cancer pathway?

A) Cancer cells acquire self-sufficiency in the signalling processes that stimulate division and growth.
B) Cancer cells are normally sensitive to signals that inhibit growth.
C) Cancer cells can evade programmed cell death.
D) Cancer cells acquire limitless replicative potential.
E) Cancer cells develop ways to nourish themselves.

Question 43

Why do c-oncs have introns whereas v-oncs do not; and how would this benefit a retrovirus?

Question 44

Blood vessels are induced to grow among cancer cells through a process known as

A) angiogenesis.
B) cardiogenesis.
C) vasculargenesis.
D) arterialgenesis.
E) None of these

Question 45

How do c-ras mutations,like the c-H ras gene,cause cancer?

Question 46

Which of the following is a proto-oncogene implicated in the formation of glioblastomas?

A) EGFR
B) PDGF
C) AST
D) EGFR and PDGF
E) All of these

Question 47

How does the START checkpoint regulates cell cycle growth,and what happens when this checkpoint is deregulated? Explain your answer by discussing the appropriate cyclins and CDK molecules and their functions.

Question 48

Which of the following human behaviors contribute to the risk of cancer?

A) Cigarette smoking
B) Exposure to UV light
C) Consumption of fatty foods
D) All of these
E) None of these

Question 49

What is the role of the tumor suppressor gene in the regulation of the cell cycle? Include in your answer discussion of at least one specific tumor suppressor gene such as pRB.

Question 50

Outline the killing events that take place during the process of apoptosis and discuss how this process can relate to the formation of cancer.