Answers Practice Midsem G & D

Surname_____________________ Surname_________________________First ____First Name_______________________ Name_________________________Student __Student ID Griffith University School of Medical Science 1005MSC (GC) – Genes and Disease Practice Mid-Semester Exam - 2013

WORKING TIME:

1 Hour

EXAMINATION TYPE:

Multiple Choice and True/False

PERUSAL INSTRUCTIONS:

10 Minutes: Students may not write during perusal

EXAMINATION INSTRUCTIONS TO STUDENTS:

At the top of each page, complete your NAME and your STUDENT ID Answer ALL Questions on the MARK SENSE CARD provided

Total Marks :

50

STUDENTS ARE PERMITTED TO BRING THE FOLLOWING MATERIALS INTO THE EXAMINATION VENUE:

DICTIONARY: Non-medical, non-electronic English Translation Dictionary Allowed

OTHER MATERIALS ALLOWED: Non-programmable calculator

THE FOLLOWING MATERIALS ARE SUPPLIED BY GRIFFITH UNIVERSITY:

MARK SENSE CARD

1005MSC Genes and Disease Practice Mid Semester Examination

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Surname_____________________ Surname_________________________First ____First Name_______________________ Name_________________________Student __Student ID

1. The centromere is a region in which A) chromatids are attached to one another. B) metaphase chromosomes become aligned. C) chromosomes are grouped during telophase. D) the nucleus is located prior to mitosis. E) new spindle microtubules form.

2. In the following pedigree, the indicated trait is caused by what type of inheritance pattern?

A) B) C) D) E)

autosomal recessive autosomal dominant X-linked recessive X-linked dominant A or C

3. Which of the following statements is not true? A) Mitosis produces new nuclei with exactly the same chromosomal endowment as the parent nucleus entering mitosis. B) Mitosis may occur without cytokinesis. C) Mitosis and cytokinesis are required for asexual reproduction. D) All cells come from a preexisting cell. E) The mitotic spindles in prokaryotic cells are composed of microtubules.

4. Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not cytokinesis, the result would be a cell with A) a single large nucleus. B) high concentrations of actin and myosin. C) two abnormally small nuclei. D) two nuclei. E) two nuclei but with half the amount of DNA. 1005MSC Genes and Disease Practice Mid Semester Examination

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5. The formation of a cell plate is beginning across the middle of a cell and nuclei are reforming at opposite ends of the cell. What kind of cell is this? A) an animal cell in metaphase B) an animal cell in telophase C) an animal cell undergoing cytokinesis D) a plant cell in metaphase E) a plant cell undergoing cytokinesis

6. The correct sequence of steps in the M phase of the cell cycle is A) prophase, prometaphase, metaphase, anaphase, telophase. B) prophase, metaphase, prometaphase, anaphase, telophase. C) prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis. D) prophase, metaphase, anaphase, telophase, cytokinesis. E) cytokinesis, telophase, prophase, prometaphase, metaphase, anaphase.

7. Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle was the nucleus with 6 picograms of DNA? A) G0 B) G1 C) S D) G2 E) M

8. If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will usually A) move directly into telophase. B) complete the cycle and divide. C) exit the cycle and switch to a nondividing state. D) show a drop in MPF concentration. E) complete cytokinesis and form new cell walls.


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Surname_____________________ Surname_________________________First ____First Name_______________________ Name_________________________Student __Student ID 9. Cells that are in a non-dividing state are in which phase? A) G0 B) G2 C) G1 D) S E) M

The following questions consist of five fi ve phrases or sentences related to the control of cell division. For each one, select select the term below that is most closely related to it. Each term may be used once, more than once, or not at all.

A. B. C. D. E.

PDGF MPF protein kinase cyclin Cdk

10. a protein maintained at constant levels throughout throughout the cell cycle that that requires cyclin to become catalytically active E

11. a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex D

12. a general term for enzymes that activate or inactivate other proteins by phosphorylating them C

13. Which of the following is true concerning cancer cells? A) They do not exhibit density-dependent densit y-dependent inhibition when growing in culture. B) The may be considered immortal C) They are not subject to cell cycle controls. D) B and C only E) A, B, and C


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14. During prophase a homologous pair of chromosomes consists of A) four chromosomes and two chromatids. B) two chromosomes and two chromatids. C) two chromosomes and four chromatids. D) one chromosome and two chromatids. E) one chromosome and four chromatids.

15. Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to A) disruption of mitotic spindle formation. B) inhibition of regulatory protein phosphorylation. C) suppression of cyclin production. D) myosin denaturation and inhibition of cleavage furrow formation. E) inhibition of DNA synthesis.

16. Which of the following differentiates between independent assortment and segregation? A) The law of segregation requires describing two or more genes relative to one another. B) The law of segregation requires having two or more generations to describe. C) The law of independent assortment is accounted for by observations of prophase I. D) The law of segregation is accounted for by anaphase of mitosis. E) The law of independent assortment requires describing two or more genes relative to one another.

17. Which of the following statements about genes is incorrect ? A) Genes correspond to segments of DNA. B) Many genes contain the information needed for cells to synthesize enzymes and other proteins. C) During fertilization, both the sperm and the ovum contribute genes to the resulting fertilized egg. D) Under normal circumstances, each chromosome contains precisely one gene. E) Genetic differences can result from changes in the DNA called mutations.


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18. Mendel crossed yellow seeded and green seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were 6022 yellow and 2001 green seeds. The allele for green seeds had what relationship over the allele for yellow seeds? A) dominant B) incomplete dominant C) codominant D) recessive E) unable to determine from the information provided

19. At which stage of mitosis are chromosomes chromosomes photographed in the preparation of a karyotype? A) prophase B) metaphase C) anaphase D) telophase E) interphase

20. There is good evidence for linkage when A) two genes occur together in the same gamete. B) a gene is associated with a specific phenotype. C) two genes work together to control a specific characteristic. D) genes do not segregate independently during meiosis. E) two characteristics are caused by a single gene.

21. In animals, meiosis results in gametes, and fertilisation results in A) spores. B) gametophytes. C) zygotes. D) sporophytes. E) clones.

22. After telophase I of meiosis, the chromosomal makeup of each daughter cell is A) diploid, and the chromosomes are composed of a single chromatid. B) diploid, and the chromosomes are composed of two chromatids. C) haploid, and the chromosomes are composed of a single chromatid. D) haploid, and the chromosomes are composed of two chromatids. E) tetraploid, and the chromosomes are composed of two chromatids.


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Surname_____________________ Surname_________________________First ____First Name_______________________ Name_________________________Student __Student ID For the following questions, match the key event of meiosis with the stages listed below.

I. II. III. IV. V. VI. VII. VIII.

prophase I metaphase I anaphase I telophase I prophase II metaphase II anaphase II telophase II

23. Tetrads of chromosomes are aligned at the center of the cell; independent independent assortment soon follows. A) I B) II C) IV D) VII E) VIII 24. Synapsis of homologous homologous pairs occurs; crossing over may may occur. A) I B) II C) IV D) VI E) VII 25. Centromeres of sister chromatids uncouple and chromatids separate. A) II B) III C) IV D) V E) VII

26. Which of the following happens at the conclusion of meiosis I? A) Homologous chromosomes are separated. B) The chromosome number is conserved. C) Sister chromatids are separated. D) Four daughter cells are formed. E) The sperm cells elongate to form a head and a tail end.


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Surname_____________________ Surname_________________________First ____First Name_______________________ Name_________________________Student __Student ID 27. In the cross AaBbCc × AaBbCc, what is the probability of producing producing the genotype AABBCC? A) 1/32 B) 1/4 C) 1/64 D) 1/8 E) 1/16

28. A plant with purple flowers is allowed to self-pollinate. Generation after generation, it produces purple flowers. This is an example of A) hybridization. B) incomplete dominance. C) true-breeding. D) the law of segregation. E) polygenetics.

29. A cross between homozygous purple-flowered and homozygous white-flowered pea plants results in offspring with purple flowers. This demonstrates A) the blending model of genetics. B) true-breeding. C) dominance. D) a dihybrid cross. E) the mistakes made by Mendel.

30. The F1 offspring of Mendel's classic pea cross always looked like one of the two parental varieties because A) one allele was completely dominant over another. B) each allele affected phenotypic expression. C) the traits blended together during fertilization. D) no genes interacted to produce the parental phenotype. E) different genes interacted to produce the parental phenotype.

31. A 9:3:3:1 phenotypic ratio is characteristic of which of the following? A) a monohybrid cross B) a dihybrid cross C) a trihybrid cross D) linked genes E) both A and D


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Surname_____________________ Surname_________________________First ____First Name_______________________ Name_________________________Student __Student ID 32. P = purple, pp = white. The offspring of a cross between two heterozygous purpleflowering plants (Pp × Pp) results in A) all purple-flowered plants. B) purple-flowered plants and white-flowered plants. C) two types of white-flowered plants: PP and Pp. D) all white-flowered plants. E) all pink-flowered plants.

33. Black fur in mice ( B) is dominant to brown fur ( b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of the cross BbTt × BBtt will have black fur and long tails? A) 1/16 B) 3/16 C) 3/8 D) 1/2 E) 9/16

34. In snapdragons, heterozygotes have pink flowers, whereas homozygotes have red or white flowers. When plants with red flowers are crossed with plants with white flowers, what proportion of the offspring will have pink flowers? A) 0% B) 25% C) 50% D) 75% E) 100%

35. Sally has just given birth to a baby girl. The medical professional involved in her care has advised Sally that mosaic Down Syndrome is suspected in her baby. Sally had received prenatal screening which had suggested a low likelihood of a Down syndrome baby, so the diagnosis came as quite a shock. A sample of the baby’s blood has been taken for karyotype karyotype analysis. If the suspected mosaicism is confirmed, the karyotype analysis is most likely to show the following: A) Three of chromosome 21 in all 20 cells analysed B) Three of chromosome 21 in some of the 20 cells analysed C) Three of chromosome 18 in all 20 cells analysed D) Three of chromosome 18 in some of the 20 cells analysed E) A translocation in all cells analysed


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Surname_____________________ Surname_________________________First ____First Name_______________________ Name_________________________Student __Student ID 36. Further to the situation described in question 35. above, the the baby’s karyotype has indeed revealed mosaic Down Syndrome. It is more likely that the molecular event leading to the mosaicism was A) a non-disjunction during meiosis I in oogenesis B) a non-disjunction during meiosis II in oogenesis C) a non-disjunction during cell division in the early embryo D) a chromosomal duplication during meiosis in oogenesis E) a chromosomal duplication during meiosis in the early embryo

37. SRY is A) a gene present on the Y chromosome that triggers male development. B) a gene present on the X chromosome that triggers female development. C) an autosomal gene that is required for the expression of genes on the Y chromosome. D) an autosomal gene that is required for the expression of genes on the X chromosome. E) required for development, and males or females lacking the gene do not survive past early childhood.

38. In the following list, which term is least related to the others? A) Duchenne muscular dystrophy B) autosome C) sex-linked genes D) color blindness E) hemophilia

39. A man who carries an X-linked allele will pass it on to A) all of his daughters. B) half of his daughters. C) all of his sons. D) half of his sons. E) all of his children.

40. Which of these syndromes afflicts mostly males? A) Turner syndrome B) Down syndrome C) Duchenne muscular dystrophy D) cri du chat syndrome E) chronic myelogenous leukemia


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41. A man who carries a Y linked allele will pass it on to A) 50% of his sons B) 25% of his sons C) all of his sons D) 75% of his sons E) none of his sons

42. Punnett squares are used for A) determining the DNA sequence of a given gene B) predicting the outcome of gene crosses C) determining the degree of gene mutation D) predicting the sex of offspring E) A and B

43. Skin colour in a fish is inherited via a single s ingle gene with four different alleles. How many different types of gametes could a fish produce for this trait? A) 4 B) 2 C) 8 D) 16 E) 1

44. The ABO blood groups in humans is an example of A) polygenic inheritance B) co-dominance C) epistasis D) lethal alleles E) linkage

45. Huntington's disease is caused by a dominant dominant allele. If one of your your parents has the disease, the probability that you, too, will have the disease is A) 50% B) 25% C) 0% D) 75% E) 12.5%


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Surname_____________________ Surname_________________________First ____First Name_______________________ Name_________________________Student __Student ID 46. Patau Syndrome is characterised by A) Trisomy 18 B) Translocation between chr13 and chr21 C) Trisomy 13 D) Trisomy 21 E) Inversion of chromosome 21

47. If the nuclei of liver cells of an animal have 24 chromosomes its sperm cells have A) 6 chromosomes B) 24 chromosomes C) 12 chromosomes D) 48 chromosomes E) 36 chromosomes

48. In animals, meiosis results in gametes, and fertilization results in A) gametophytes B) zygotes C) mosaics D) disjunction E) ova

49. The synaptonemal complex disappears during A) late prophase of meiosis I B) late prophase of meiosis II C) early anaphase of meiosis I D) early anaphase of meiosis II E) early prophase of meiosis I and II

50. In a cell in which 2 n = 6, the independent assortment of chromosomes during meiosis can by itself give rise to how many genetically different gametes. A) 8 B) 16 C) 4 D) 10 E) 6

END OF EXAM


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Answers Practice Midsem G & D

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