Deck 24: Cell Cycle, Programmed Cell Death, and Cancer

Question 1

All of the following are true EXCEPT

A) p53 is a transcription factor that regulates cell cycle events.
B) p53 is associated with Li_Fraumeni syndrome.
C) p53 binds and regulates the activity of the E2F transcription factor.
D) p53 mutations are frequently found in the early stages of skin cancer.
E) p53 mutations reduce the severity of sunburn.

Answer 1

p53 binds and regulates the activity of the E2F transcription factor.

Question 2

How many times can a normal epithelial cell divide before reaching senescence?

A) 1
B) 2
C) 20
D) 50
E) 100

Answer 2

50

Question 3

What RAS activation step promotes interaction with the membrane?

A) Acetylation of N-terminal amino acid
B) Addition of farnesyl fatty acid
C) Addition of multiple phosphate groups
D) Dimerization
E) Formation of disulfide bonds

Answer 3

Addition of farnesyl fatty acid

Question 4

If an activating mutation in a single allele of a protogene is adequate to cause cancer to progress, what type of inheritance does this display?

A) Autosomal dominant
B) Autosomal recessive
C) Codominant
D) X-linked
E) Y-linked

Question 5

The phase in the mammalian cell cycle when the replicated chromosomes are segregated into the daughter cells is

A) Go.
B) G1.
C) S.
D) G2.
E) M.

Question 6

All of the following are characteristic of human RAS genes EXCEPT that

A) they encode proteins that have GTPase activity.
B) they are frequently found mutated in spontaneous human tumors.
C) they encode proteins of closely related structure.
D) they function as tumor suppressor genes.
E) they can gain an ability to transform cells when mutated.

Question 7

What ion is necessary for the function of metallo proteases?

A) Ca2+
B) Mg2+
C) Mn2+
D) Na+
E) Zn2+

Question 8

Which of the following statements, if any, is true about the RAS protein?

A) The RAS gene has a GC rich promoter region and contains a TATA box.
B) It directly acts upon nuclear proteins.
C) Its activity is inhibited by the GAP-stimulated, intrinsic GTPase activity.
D) It undergoes no post-translational modification.
E) None of the above.

Question 9

What type of proteases are linked to apoptosis?

A) Caspases
B) Collagenases
C) Elastases
D) Metalloprotease
E) Serine proteases

Question 10

Which one of the following nuclear RNA processing events is correct?

A) Many RNA transcripts have a cap of 7-methyl-guanine added to the end of the RNA.
B) The splice sites in precursors to mRNA are initially recognized by an enzyme that marks them by methylation.
C) A poly G tail of up to about 200 guanine residues is added to the end of most pre-mRNA molecules.
D) The 5' -end of many RNAs is capped using a 5 -5 link.
E) After synthesis of RNA on the DNA template, ribothymidine residues in the RNA are demethylated to uridine residues.

Question 11

What type of inheritance do tumor suppressor genes display?

A) Autosomal dominant
B) Autosomal recessive
C) Codominant
D) X-linked
E) Y-linked

Question 12

What do most mutations in RAS affect?

A) Binding to GAPRAS
B) Binding to Grb2
C) Binding to growth factor
D) GDP/GTP exchange
E) Hydrolysis of GTP

Question 13

Which is the most prominent protooncogene?

A) Bcl2
B) E2F
C) Fas
D) Jun
E) RAS

Question 14

How does the persistence of telomerase in cancer cells enable immortality?

A) Decrease in metastasis
B) Degradation of tumor suppressor proteins
C) Increase in rate of meiosis
D) Prevention of shortening of DNA
E) Promotion of angiogenesis

Question 15

Which protein prevents leakage through the mitochondrial pore?

A) Bad
B) Bak
C) Bax
D) Bcl-XL
E) Bid

Question 16

How is the binding of MdM2 to p53 inhibited?

A) Deacetylation of p53
B) Decrease inApaf1 expression
C) Dimerization of p53
D) Phosphorylation of p53
E) Ubiquitination of MdM2

Question 17

In which phase of the cell cycle is M-cyclin synthesized?

A) G0
B) G1
C) G2
D) M
E) S

Question 18

Which of the following statements is true?

A) p53 belongs in the category of oncogenes.
B) p53 is directly activated by the normal RAS protein.
C) Mutant p53s can contain either loss of function or gain of function mutations.
D) Mutant p53s are rarely found in human cancers.
E) Mutant p53s are located in the cellular membrane.

Question 19

What does necrosis result in that apoptosis does not?

A) Blebbing of cell membrane
B) Cell death
C) Engulfing of cells by phagocytic cells
D) Inflammatory response
E) Laddering of nuclear DNA

Question 20

What is the role of unphosphorylated retinoblastoma protein?

A) Phosphorylation of cyclins
B) Promotion of protein synthesis
C) Removal of phosphates from CDKs
D) Sequestration of translation factor E2F
E) Ubiquitination of proteins

Question 21

In the RAS signaling cascade what moves from the cytosol to the nucleus?

A) Grb2
B) MAPK
C) MAPKK
D) MAPKKK
E) RAS

Question 22

What is a "promoter" in the context of carcinogenicity?

A) A back mutation in an oncogene
B) A specialized microarray used to diagnose mutations
C) A vitamin deficiency that results in DNA strand breaks
D) An environmental factor that acts as a growth factor
E) An enzyme that catalyzes antioxidant reactions

Question 23

What is the carcinogenic mechanism of the papilloma virus?

A) Decrease in angiogenesis
B) Decrease in ubiquitination of Rb
C) Down-regulation of S-phase proteins
D) Increase in apoptosis
E) Release of E2F from Rb

Question 24

What is the role of FGF (fibroblast growth factor) and VEGF (vascular endothelial cell growth factor) in the progression of cancer?

A) Angiogenesis
B) Binding to tumor suppressor genes
C) Induction of synthesis of p53
D) Inhibition of contact inhibition
E) Release of E2F from Rb

Question 25

Where is plasminogen synthesized?

A) Adrenals
B) Intestine
C) Kidney
D) Liver
E) Lungs

Question 26

How does Rb protein work as a suppressor protein?

A) Degradation of the Bak, Bad, and Bax proteins
B) Excision of protooncogene from DNA
C) Increase in p21 synthesis
D) Inhibition of cytochrome c release from the mitochondrion
E) Sequestration of an elongation factor

Question 27

An increase in levels of which protein promotes DNA repair and cell death?

A) APC
B) M-cyclin
C) p53
D) Rb
E) Wee1

Question 28

Which two mitochondrial proteins enter the nucleus to promote DNA degradation?

A) AIF and endoG
B) XIAP and Smac
C) Apaf1 and caspase-9
D) Bax and Bak
E) Bcl2 and Bcl-XL

Question 29

Protooncogenes are:

A) viral genes that lead to cancer when inserted into mammalian genomes
B) human counterparts of viral genes that cause cancer
C) always have a dominant phenotype when introduced into cells
D) the same as tumor suppressor genes
E) are rarely mutated in human cancers

Question 30

What is the first thing that happens after growth factors bind extracellular receptors?

A) Activation of G-proteins
B) Formation of a covalent bond between growth factor and receptor
C) Increased phosphatase activity
D) Oligomerization of membrane proteins
E) Phosphorylation of receptor tyrosines

Question 31

When in the cell cycle is the decision made between cell death and cell division?

A) End of G2
B) End of S
C) Start of G2
D) Start of M
E) Start of S

Question 32

What is the meaning of the name of APC (anaphase-promoting complex)?

A) Inhibition of DNA synthesis
B) Inhibition of mitosis
C) Progression of cell into G0
D) Regeneration of plasma membrane
E) Separation of sister chromatids

Question 33

What is the name of the protein that acts as an intracellular adaptor in the extrinsic "death pathway"

A) Bak
B) Bax
C) DISC
D) FADD
E) Procaspase 8

Question 34

In primary epithelial cell culture, how many cellular changes have been shown to be the minimum required for transformation into a cancer phenotype?

A) 1
B) 4
C) 10
D) 50
E) 100

Question 35

The normal cellular product of a tumor suppressor gene

A) functions in signal transduction.
B) facilitates somatic recombination.
C) is produced by oncogenic viruses.
D) causes cancer when over expressed.
E) inhibits cellular proliferation.

Question 36

A tumor suppressor gene DIFFERS from an oncogene in that

A) the presence of a normally functioning protein product from a tumor repressor gene is required to initiate oncogenesis.
B) the presence of an altered protein product from a tumor suppressor gene is required to initiate oncogenesis.
C) deletion of both alleles is tumorigenic for an oncogene but may not be for a tumor suppressor gene.
D) deletion of both alleles is tumorigenic for a tumor repressor gene but is not for an oncogene.
E) amplification of a tumor suppressor gene results in oncogenesis.

Question 37

Transformation by DNA tumor viruses

A) is a consequence of their ability to synthesize reverse transcripts of oncogenes.
B) is a consequence of their ability to up-regulate nearby proto-oncogenes following integration of the viral genome into the host chromosome.
C) occurs in cells that are permissive to the replication of the viral genome.
D) results from the inappropriate, persistent induction of S phase.
E) B, C, and D are all correct.

Question 38

Which of the following statements pertaining to oncogenes is CORRECT?

A) Oncogenes derive from normal cellular genes involved in growth control termed "proto_oncogenes. "
B) A mutation that creates an oncogene can affect cell behavior even in the presence of a normal copy of the corresponding protooncogene.
C) Oncogenes generally differ from their normal counterparts as a consequence of a germline mutation (i.e., transmitted vertically from parent to offspring).
D) Both A and B are correct.
E) A, B, and C are all correct.

Question 39

What gene is transcribed when p53 levels rise?

A) Fos
B) Jun
C) Smac
D) Waf1/cip1
E) Wee1

Question 40

With regards to the normal p5 protein, which of the following statements, if any, are true?

A) It is located in the cytoplasm, is an oncogene and its presence in cells can lead to a decreased incidence of tumor formation.
B) It is located in the nucleus, is an oncogene and its absence in cells can lead to a decreased incidence of tumor formation.
C) It is located in the nucleus, is a tumor promoting protein and its presence in cells can lead to an increased incidence of tumor formation.
D) It is located in the nucleus, is a tumor suppressor protein and its absence in cells can lead to an increased incidence of tumor formation.
E) None of the above.

Question 41

What is the name of the shortened chromosome associated with leukemia?

A) Dallas
B) Miami
C) Omaha
D) Philadelphia
E) Sacramento

Question 42

Which is a property of a tumor suppressor pathway?

A) Inhibition of apoptosis
B) Inhibition of metastasis
C) Promotion of angiogenesis
D) Promotion of cell division
E) Promotion of immortality

Question 43

Which of the following statements, if any, is false concerning the RAS protein?

A) It can become oncogenic as a result of a single amino acid substitution.
B) It can bind the guanine nucleotides GTP and GDP.
C) It can cycle between an inactive GTP-bound state and an active GDP-bound state.
D) It has intrinsic GTPase activity.
E) None of the above.

Question 44

How is the inhibitory phosphate removed from the M-CDK/M-cyclin complex?

A) APC
B) Dissociation from M-CDR
C) M-Cdc25
D) M-Wee1
E) Ubiquitination

Question 45

Which protein is involved in mitochondrial pore formation?

A) Bad
B) Bax
C) Bid
D) Noxa
E) PUMA

Question 46

To what family of proteins do ERK and JNK belong?

A) Akt
B) MAPK
C) MAPKK
D) MAPKKK
E) Raf

Question 47

Which is a property of an oncogene pathway?

A) Inhibition of angiogenesis
B) Inhibition of immortality
C) Inhibition of metastasis
D) Promotion of apoptosis
E) Promotion of cell division

Question 48

By what mechanism does Smac/DIABLO promote apoptosis?

A) Degradation of DNA
B) Induction of Bak
C) Inhibition of caspase inhibitors
D) Inhibition of caspases
E) Prevention of loss of cytochrome c from the mitochondrion

Question 49

Which intramitochondrial protein is often extruded from the mitochondrion through pores generated by Bcl-2-like pro-apoptotic proteins?

A) Cytochrome bc1
B) Cytochrome c
C) Cytochrome oxidase
D) NADH dehydrogenase
E) Succinate dehydrogenase

Question 50

Which of the following statements about the cell cycle is/are true?

A) In cancer cells, the cell cycle is shortened primarily as a result of shortening of the S phase.
B) Regulation of the rate of growth of the cells appears to be controlled by regulation of the rate of DNA synthesis during S phase.
C) RNA synthesis and protein synthesis are not required for the synthesis of DNA in S phase.
D) Differentiated tissues such as muscle cells remain in G1 phase.

Question 51

What proteins are increased in the membranes of metastatic cancer cells?

A) Collagen helices
B) Cytokines
C) Laminin receptors
D) Proteases
E) Urokinases

Question 52

Which phase of the cell cycle occurs in the shortest time?

A) G0
B) G1
C) G2
D) M
E) S

Question 53

The key transition point in the cell cycle, subject to regulation by both protooncogenes and tumor suppressor genes, is:

A) G2-M
B) GO-G1
C) G1-S
D) M-G1
E) S-G2

Question 54

What is the function of Grb2?

A) A GTP/GDP exchange protein
B) Acting as an adaptor protein with no enzymatic activity
C) Binding to GAPRAS protein
D) Phosphorylation of adenylcyclase
E) Phosphorylation of GEFRAS protein