01:447:380 Lecture 23: Cancer Genetics

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olivebee315

11 Dec 2017

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Retinoblastoma (caused by 2 mutations, hypothesis explains genetic bases of usually develops in only one eye; if bilateral, age of onset is early and close relatives are also affected) Immortal cancer cells evade normal cell-death programs (apoptosis) 4: can metastasize and invade other tissues, can form blood vessels. 1: migrant populations take on cancer incidence of host country within a, cause somatic mutations, examples: tobacco use, diet, obesity, alcohol, radiation exposure (uv or. Incidence rate of different cancers varies throughout the world single generation: environmental factors that influence cancer development ionizing), chemical exposure. Fos: tumor suppressor genes: codes for protein product that inhibits cell division, mutations are recessive must be het to show phenotype (often predisposed to cancer, example: control cell cycle: , loss of heterozygosity. Can bind to gf: receptor changes conformation (dephosphorylated) can associate with ras(gdp) ras binds gtp and is activated, active ras(gtp) functions to activate raf protein and other proteins stimulates cell cycle.

Related Questions

QuestionGroup: #21 Gene expression 2

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The direct end result of gene expression is which of the following?

Amino acids

Translation

Proteins

Carbohydrates

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QuestionGroup: #22 Mutation

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Which of the following is the ways in which nucleotide mutations lead to altered proteins?

One nucleotide is substituted by another nucleotide, which can cause an early stop codon to be incorporated into the amino acid sequence resulting in a truncated protein.

One nucleotide is replaced by another nucleotide, which can change an amino acid in the protein sequence

Nucleotides are inserted into a nucleotide sequence causing a frameshift in the sequence.

All three choices may cause mutations.

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QuestionGroup: #23 Mutation 2

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Mutations are the result of which of the following?

Change in the normal nucleotide sequence in the DNA directly resulting in different carbohydrates

Change in the normal nucleotide sequence in the DNA directly resulting in different proteins

Change in the order of transfer RNA to messenger RNA so that the transfer RNA take over the role of Messenger RNA

Primarily an alteration in the sequence of nucleotides in the abnormal proteins

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QuestionGroup: #24 Cell division

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There are two major kinds of cell division. Which of the following plays a major role in promoting genetic diversity?

Meiosis since it causes the cells to make more daughter cells than mitosis

Mitosis since it causes the cells to duplicate and eventually have mutations

Meiosis since it causes the DNA sequences to be separated into new patterns in the daughter cells.

Mitosis since it essential for the ovaries in humans to separate and duplicate

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QuestionGroup: #25 Cancer

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Genes that slow down or stop the cell cycle are called...

Apoptotic genes

Oncogenes

Restriction genes

Tumor suppressor genes

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QuestionGroup: #26 Cancer2

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The common theme in the development of all cancers is...

Mutation

Evolution

Infection

Syncopation

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QuestionGroup: #27 Genetics

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Punnett's square is which of the following?

Example of all possible combinations of alleles

Example of all possible combinations of chromosomes

Example of only certain combination of alleles since some will not be expressed.

Example of all possible combinations of DNA

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QuestionGroup: #28 Embryo development

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Which of the following is the end of the cleavage phase?

A fetus

Formation of a blastocyst

Implantation to the lining of the uterus

Fewer number of cells

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QuestionGroup: #29 Development of organ system

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For organs to be differentiated, which of the following is the first step?

Stem cells trigger the development of differentiated cells

Tissues assemble into organ systems such as blood

Tissue specific genes in stem cells are triggered

Differentiated cells form tissues

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QuestionGroup: #30 Development and society

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A pregnant mother ingests a chemical which her mother said would be great for the baby. When the baby was born, it had a large head and flippers for arms. What caused this phenotype?

The chemicals were teratogens which influenced oxidative phosphorylation causing the changes in the phenotype.

The chemicals influenced the expression of different stem cells.

There is no way to assume the chemicals caused the phenotype since we have no data on other mothers who took this medicine. It could have been purely by chance.

The chemicals were teratogens which caused the baby to show early signs of evolution.

1. In Humans, many types of cancers have been linked to?

A. Duplications
B. Inversions
C. translocations
D. deletions
E all of these

2. 5- bromoouracil is mutagenic because it is a(n)

a. base-modifying agent
b. base analog
c. intercalating agent
d. alkylating agent.

3.Ultraviolet radiation creates __________ in DNA

A. 5-methyl cytosine residues
B. breakages
C point mutations
D. mutational hot spots
E thymine dimers

4. The telomeres of chromosomes is composed of

A. heterochromatin
b. nucleosome
c. histone
d. achromatic

5. In eukaryotes, a replicon is

a. the distance between the origin of replication and thetermination of replication
b. a single chromosome
c. the entire genome
d. one DNA strand of a single chromosome

6. In a nonreciprocal interchomosomal translocation, a segment of achromosome is

a. exchanged with an identical segment on a differentchromosome
b. exchanged with an identical segment on a sister chromatid
c. transferred to a different chromosome without a reciprocalexchange of genetic material
d. transferred to a new location on the same chromosome without areciprocal exchange of genetic material

7. Somatic mutations are always.

a. spontaneous
b. carcinogenic
c. heritable
d. lethal
e. none of these

8. A woman with an XO genotype is

a. aneuploid
b. euploid
c. diploid
d. poluploid

9. Spontaneous mutations may occur as a result of

a. all of these
b. errors in DNA replication
c. transposition
d. none of these
e. normal cell biochemistry

10. In the semi conservative model of DNA replication, progenydouble helices consist of

a. one parental DNA strand and one new strand
b. one parental DNA strand and one new RNA strand
c. two new RNA strands
d. two parental DNA strands
e. two new DNA strands

11. A mutation in a gene may alter a cellâs

a. phenotype
b. genotype and phenotype
c. genotype

12. During replication, the direction of synthesis of new DNA fromthe leading strand is

a. both 5â to 3â and 3â to 5â
b. none of these
c. 3â to 5â
d. from left to right only
e. 5â to 3â only

13. A mutation that results in a switch from a purine-pyramidingbase pair to a pyramiding-purine base pair is a _________mutation.

a. neutral
b. transition
c. missense
d. transversion
e. nonsense

14. A trisomic human cell would contain how many chromosomes?

a. 45
b. 46,
c. 47.
d. 48

15. In a strand of DNA, a _____________ bond connects the phosphategroup of one nucleotide to the sugar of the adjacentnucleotide

a. hydrogen
b. ester
c. phosphodiester
d. phosphate
e. disulfide

16. Cri-du-chat syndrome is caused by which type of chromosomalmutation?

a. deletion
b. duplication
c. translocation
d. transversion
e. inversion

17. During replication, the role of DNA primase is to

a. add nucleotide to the growing DNA chain
b. synthesize a short chain for RNA
c. untwist the double helix at the origin of replication
d. relax the super coiling of the double helix
e. synthesize the primo some

18. A(n) ____________ inversion involves the Centro mere

a. chromocentric
b. paracentric
c. epicentric
d. percentric
e. concentric

19. Which of the following substances mutates DNA by intercalatingbetween adjacent base pairs?

a. methyl methane sulfonate
b. all of these
c. nitrous acid
d. 2-amino urine
e. acridine orange

20. A molecule of RNA is always

a. double stranded
b. helical
c. nonparallel
d. all of these
e. none of these

21. Mutagenesis of cells using radiation or a chemicalintercalating agent could be used to create __________ mutations ina region of DNA.

a. random
b. both random and site-specific
c. site-specific

22. In Griffithsâs tranformation experiments, the mice died whenthey were injected with

a. living, no virulent bacteria
b. living, virulent bacteria
c. heat-killed, no virulent bacteria
d. living, nonvirulent bacteria
e. both B and D

23. A monoploid human cells

a. shows only the excessive phenotype of all these genes
b. would be functionally impaired
c. is normal
d. would not survive

24. Gametes containing an abnormal number of chromosomes may occuras a result of

a. paracentric inversion
b. reciprocal translocation
c. disjunction of chromosomes
d. unequal crossing over

25. DNA may be altered as a result of _____________ events thatoccur normally in cells

a. depurination
b. deamination
c. depyrimidation
d. all of the above
e. none of the above

26. Which enzyme prevents DNA from tangling up as the replicationfork migrates during replication?

a. DNA polymerase I
b. DNA helicase
c. topoisonmerase
d. DNA polymerase III
e. DNA gyrase

27. Which of the following enzymes play an important role in DNAreplication?

a. DNA helicase
b. DNA ligase
c. DNA primase
d. all of them
e. DNA polymerase III

28. A mutation gene sustains a mutation that restores the originalphenotype, This is a

a. frame shift mutation
b. transversion
c. reversion
d. transition
e. forward mutation

29. A dicentric chromosome has two

a. telomeres
b. mutations
c. arms
d. centromeres

30. Which type of chromosomal mutation cannot revert to thewild-type state

a. duplication
b. deletion
c. translocation
d. both A and C
e. all of them

31. Translation of histone mRNAs occurs during which phase of theeukaryotic cell cycle?

a. M
b. G1
c. G2
d. S
e. all of these

32. After removal of the RNA primers, Okazaki fragments are joinedthrough a reaction that involves which enzyme?

a. RNA polymerase
b. DNA helicase
c. DNA polymerase
d. DNA primase
e. DNA ligase

33. Which of the following is required for the synthesis of DNAduring replication?

a. DNA polymerase
b. magnesium ions
c. all of them
d. template DNA
e. dNTPs

34. Most of the genome of an active cell consists of

a. heterochromatin
b. histochromatin
c. poluchromatin
d. euchromatin

35. In eukaryotes, DNA replication begins,

a. a single origin of replication on each chromosome
b. a single origin of replication on each chromosome
c. multiple origins of replication on each chromosome
d. all of the above
e. none of the above

36. A human cell contains 2 sets of 24 chromosomes is

a. euploid
b. haploid
c. polyploid
d. aneuploid

37. Pseudodominance occurs as a result of which type ofmutation?

a. translocation
b. duppolication
c. all of these
d. point mutation
e. deletion

38. The enzymatic activity of a telomerase is best described asa

a. none of these
b. polymerase
c. ligase
d. reverse transcriptase
e. topoisomerase

39. A Barr body is an example of

a. constitutive heterochromatin
b. facultative heterochromatin
c. facultative euchromatin
d. constitutive euchromatin

40. An addition or deletion of one or two base pairs in a genecauses a ____________ mutation

a. Transition
b. frameshift
c. nonsense
d. transversion
e. neutral

41. A heterozygous chromosomal inversion can be detected

a. by cytogenetic observation of loops in chromosomes
b. through genetic studies indicating a decrease in the frequencyof recombination between genes
c. by observing a decrease in the number of viable progenyfollowing genetic crosses
d. all of the above

42. The mutagen 5-bromouracil is an analog of which base?

a. adenine
b. threonine
c. thymine
d. cystosine
e. uracil

43. A mutation that changes a codon from one that represents anamino acid to one that signals a chain termination is a______________ mutation.

a. neutral
b. missense
c. frame shift
d. nonsense

44. A chromosomal mutation that results in an increase in theamount of DNA is a(n)

a. duplication
b. inversion
c. deletion
d. both A and C
e. all of the above

45. Prior to replication, the DNA double helix must be untwisted bywhich type of enzyme?

a. topoisomerase
b. ligase
c. polymerase
d. helicase
e. primase

46. In his transformation experiments, Griffiths used cultures ofwhich bacterium?

a. Sacchromyces cerevisiae
b. Escherichia coli
c. Streptococcus pneumoniae.
d. Bacillus cereus
e. Eneterococcus faecalis

47. A mutation changes a codon from a UCG to a UAG. This is a____________ mutation?

a. point
b. nonsense
c. silent
d. both A and B
e. all of the above

48. In eukaryotes, DNA replication

a. is initiated at several sites on chromosomes
b. occurs bidirectional
c. is semidiscontinuous
d. all of the above
e. none of the above

49. Which of the following bacteria are used in the Amestest?

a. Pseudomonas aeruginosa
b. Escherichia coli
c. Vibrio cholera
d. Salmonella typhimurium
e. Rickettsia rickettsii

50. Which of the following changes represents a missensemutation?

a. UGA (stop) to UAG (stop)
b. AAA (lysine) to AGA (arginine)
c. UUU (phenylalanine) to UAA (stop)
d. AUG (methionine) to UGA (stop)
e. AAA (lysine) to AAG (lysine)

On the Edge Selling Personalized Genetics

Several companies on the Internet sell genetic tests directly to consumers including 23andMe, Navigenics, decode Genetics, DNA Tribes, Genelex, ScientificMatch, Consumer Genetics, Salugen, DNAprint Genomics, Genova Diagnostics, Suracell, and many more. The companies ask customers to collect a sample of their genes with a cheek swab and send it to them for testing. Most test by putting the customerâs gene sample on a small flat âDNA microarray chipâ that already contains pieces of DNA matching known genes (or gene mutations). If one of the customerâs genes matches one of the pieces of DNA on the chip, it binds to the DNA fragment which creates a tiny fluorescent glow showing that the gene indicated by the DNA fragment is in the sample. A computer then analyzes the pattern of glowing spots on the chip and prints out a list of the genes (or gene mutations) in the customerâs sample. Scientists have discovered a few genes that are associated with specific diseases or personal characteristics. Studies found, for example, genes that are linked to cystic fibrosis, Tay Sachs disease, and Lou Gehrigâs disease, genes that increase the risk of certain breast, colon, and thyroid cancers, and genes associated with sensation seeking, eye color, obesity, and lactose intolerance. They also found that some genes are more often found in people whose ancestors came from certain regions of the world. The companies say that based on these studies and their own gene tests, they can give customers valuable personalized information (for a price, of course). One company, Sciona, (no longer operating) said on its website: âSciona is a leader in nutrigenomics, the science of personalizing your nutrition and lifestyle choices to match your genesâ; Sciona gave customers âa personalized preventative dietary regimeâ that was supposed to prevent the diseases their genes put them at risk for. Another site promises: âBased upon the . . . [genetic] analysis, Suracell recommends to each client a personalized regimen of nutraceuticals [vitamin supplements].â Another states: âDNA Tribes . . . uses genetic material . . . to measure your genetic connections to individual ethnic groups and major world regions.â Another company claims to do it all: âWith a simple saliva sample weâll help you gain insight into your traits, from baldness to muscle performance. Discover risk factors for 95 diseases. Know your predicted response to drugs, from blood thinners to coffee. And uncover your ancestral origins.â Critics claim, however, that with a few exceptions, most studies have shown only weak connections between genes and specific traits, disease risks, drug responses, nutritional or vitamin needs, or ancestral origins. Many studies that link specific genes to a disease are only preliminary and the full picture has not yet been worked out. Moreover, critics say, it is wrong to tell customers their genes put them at risk of a deadly disease without proper counseling, especially when the scientific studies are weak and many other environmental, demographic, and lifestyle factors determine the actual onset of a disease. Ordinary consumers, they conclude, are being sold a product that they do not have the expertise to interpret. But defenders of the tests say consumers have a right to know what genes they carry and what science has learned about those genes. The companies charge from $140 to test for two or three genes, up to $999 to test for a full suite of genes. Evaluate the ethics of selling gene tests directly to consumers like these companies are doing. What would each of the three theories of a businessâs duties to consumers say about what the companies are doing? Under what conditions do you think selling the tests would be ethically legitimate? Check out the video of GAO interviews of gene-test company salespeople at http://www.gao.gov/products/gao-10-847t .

Based on this issue evaluate the ethics of selling gene tests directly to consumers. Watch the video showing GAO interviews of the gene-test company salespeople and evaluate the ethics of the selling practices shown on the video. Answer the following questions:

1. What would the three theories of business's duties to consumers say about what the companies are doing?

2. Is it ever ethical for direct-to-consumer selling of these tests?

3. Should the government-on its own discretion-be able to use the DNA data in the databases to solve crimes and catch criminals?

http://www.gao.gov/products/GAO-10-847T

01:447:380 Lecture 23: Cancer Genetics

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