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54 Cards in this Set
- Front
- Back
1. A genetic _____ indicates the distances between gene loci measured in terms of the frequency of recombination. |
A. map |
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2. Of the 23 pairs of human chromosomes, 22 pairs are homologous and are found in both males and females. These are called ________. |
B. autosomes |
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3. Traits that are controlled by genes located on the X chromosome are said to be ________________. |
C. sex-linked |
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4. Allele pairs are most likely to assort independently of one another when |
E. they are on different chromosomes. |
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5. The number of allele pairs that assort independently in an organism is generally much higher than the number of chromosome pairs. This phenomenon is due to |
C. crossing over. |
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6. The theory of chromosomal inheritance was first proposed by |
D. Sutton |
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7. In Drosophila, the sex of an individual is determined by |
B. the number of X chromosomes. |
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8. In Morgan's experiments, the white eye allele in Drosophila was shown to be |
A. located on the X chromosome. |
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9. The geneticist who discovered the white eye mutation in Drosophila and helped establish that genes are carried on chromosomes was |
E. Morgan. |
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10. Genetic exchange between 2 homologous chromosomes is called |
C. crossing over. |
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11. Occasionally, chromosomes fail to separate during meiosis, leading to daughter cells that have an abnormal number of chromosomes. This phenomenon is called |
B. nondisjunction. |
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12. Humans who have lost one copy of an autosome are called |
D. monosomic. |
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13. In humans, individuals with trisomy of the ______ chromosome are most likely to survive until adulthood. |
E. 21st. |
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14. If a human female has 2 Barr bodies per cell, it is almost certain that |
C. she developed from a fertilized egg with 3 X chromosomes. |
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15. A human female with only one X chromosome is said to have a condition called |
C. Turner syndrome. |
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16. The most common fatal genetic disorder of Caucasians is |
B. cystic fibrosis. |
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17. In sickle cell anemia, the defective hemoglobin differs from the normal hemoglobin by |
C. a single amino acid substitution. |
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18. Hemophilia is caused by a |
A. recessive allele on the X chromosome. |
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19. _______________ is a human hereditary disease that is caused by a dominant allele but does not show up in affected individuals until they are in middle age. |
D. Huntington's disease |
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20. Amniocentesis is a procedure that is normally used |
D. for diagnosis of genetic disorders. |
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21. Huntington's disease is caused by a single dominant allele. It is a lethal disease, yet it persists in the human population. Which of the following statements best describes why? |
D. Huntington's disease presents symptoms in mid-life, after most people have already had offspring. |
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22. In humans, the male has an X and a Y sex chromosome. The human female has two X chromosomes. In birds, the female has a Z and a W sex chromosome while the male has two Z chromosomes. Which of the following statements is accurate about which parent determines the gender of the offspring? |
C. In humans, the male determines the gender of the offspring, and in birds the female determines the gender. |
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23. Sickle cell anemia is caused by a defect in the |
A. oxygen-carrying pigment hemoglobin. |
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24. How many Barr bodies does a normal human female contain in each diploid cell? |
B. 1 |
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25. A test cross can be used to do all of the following except |
D. identify the chromosome on which a gene is located. |
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26. Which of the following animals is a genetic male? |
B. grasshopper XO |
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27. In humans, if non-disjunction led to an individual with a genotype of XO, that person would |
A. be female because each cell lacks a Y chromosome. |
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28. In humans, if non-disjunction led to an individual with a genotype of XXY, that person would |
B. be male because each cell has one Y chromosome. |
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29. In some species, sex determination is influenced by environmental temperature during development. If you wanted to determine the temperature at which one would obtain a 1:1 sex ratio in a particular species of turtle, which of the following experiments would best address this question? |
D. Grow the turtles in five different incubators at temperatures of 22ºC, 24ºC, 26ºC, 28ºC, and 30ºC. |
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30. Any genetic differences between individuals in a population are called |
C. polymorphisms. |
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31. The classic experiments performed by Creighton and McClintock in Maize |
D. provided evidence for the physical exchange of genetic material between homologues. |
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32. In humans, if an XY individual had a deletion of the SYR gene, that person would |
A. develop as a female. |
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33. Which statement about calico cats is false? |
A. Calico cats can be male or female. |
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34. If an XY human had a genetic disorder that causes insensitivity to androgens, that person's genotype and phenotype would be |
C. XY, female. |
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35. Which offspring inherit all their mitochondrial DNA from their mother and none from their father? |
C. both sons and daughters |
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36. Nondisjunction of a single pair of autosomes can lead to all of the following except |
D. euploidy. |
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37. If you needed to determine the order of genes on a chromosome, you should perform |
C. a three-point cross. |
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38. A 39-year-old woman is in her sixth week of pregnancy. Due to her advanced age, she is at higher risk for having a baby with Down's syndrome than younger pregnant women. She would like to find out as early as possible whether or not her baby has Down's syndrome. Her doctor should suggest |
C. chorionic villi sampling. |
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39. In Drosophila, dosage compensation is controlled by the male-specific lethal (MSL) complex consisting of MSL proteins and roX RNAs. Based on what you know about dosage compensation, the role of the MSL complex in males would be to |
A. double the level of expression of genes on the X chromosome. |
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40. Given that these 2 gene loci are very closely linked, the genotypic ratio in the F2 generation should be closest to |
A. 1:2:1 |
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41. Given that these 2 gene loci are very closely linked, the phenotypic ratio in the F2 generation should be closest to |
B. 1 brown, thin: 2 red, thin: 1 red, heavy |
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42. What would be the results of a test cross with the F1 flies? |
A. 1 brown, thin: 1 red, heavy |
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43. What is the relationship between recombination frequency and the actual physical distance on a chromosome? |
C. As physical distance increases, the recombination frequency first increases in a linear fashion, but gradually levels off to a frequency of 0.5. |
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44. In a two-point cross to map genes A and B, you obtained 98 recombinant types and 902 parental types among the offspring. How far apart are these genes? |
A. 9.8 cM |
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45. Morgan's student Sturtevant demonstrated that the recombination frequencies between a series of linked genes is additive. Examine the following recombination data from Sturtevant, and determine the proper order of the genes on the Drosophila X chromosome. Assume y is in the 0.0 position. |
B. y w v m |
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46. Which of the following will help you distinguish between the two final suspects? |
A. single nucleotide polymorphisms (SNPs) |
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47. Why can't you use mitochondrial DNA to distinguish between these two suspects? |
B. The brothers share the same mitochondrial DNA. |
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48. In some human populations, the proportion of individuals who are heterozygous for the sickle cell allele is much higher than would be expected by chance alone. Why? |
D. Heterozygous individuals have an advantage over individuals with two normal alleles. |
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49. A deletion of a particular stretch of chromosome 15 can cause either Prader-Willi syndrome or Angelman syndrome, depending on |
A. the parental origin of the normal and deleted chromosome. |
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50. How did the development of anonymous markers aid in the production of a human genetic map? |
A. Anonymous markers are genetic markers that do not cause a detectable phenotype, but can be detected by molecular techniques. The markers correspond to specific and unique chromosomal regions, thereby allowing for the identification and ordering of particular segments of DNA. Such information was essential to the generation of a human genetic map. |
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51. Why isn't mitochondrial DNA a unique identifier? |
B. Mitochondrial DNA is inherited through the maternal lineage. All offspring inherit their mother's mitochondria, and therefore the same mitochondrial DNA. As a result, all family members that share a maternal lineage would have the same mitochondrial DNA. Mitochondrial DNA can therefore be used to confirm or eliminate a person's relationship within a maternal line, but cannot be used to identify a specific individual. |
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58. Suppose you are carrying out a series of crosses with an insect where the mechanism of sex determination is unknown. You discover a mutant female with short bristles and decide to cross it with a wild type male that has normal bristles. Half of the F1 progeny have short bristles but all of these short-bristled F1 progeny are males. Based on these results, a valid hypothesis would be |
D. Males are ZZ, females are ZW, and short bristles are caused by a dominant allele on the Z chromosome |
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59. In 1910, Morgan did a series of experiments with the fruit fly Drosophila, an organism where females are XX and males are XY. When a mutant male fly with white eyes was crossed with a wild type female with red eyes, none of the F1 progeny had white eyes but 18% of the F2 progeny had white eyes. Unexpectedly, all of these white-eyed F2 flies were males. Based on these results, Morgan concluded that white eyes is caused by a recessive X-linked allele. Suppose Morgan has found that half of the F1 progeny had white eyes but all of these white-eyed F1 flies were females. In this case, a valid hypothesis would be |
C. White eyes is caused by a dominant X-linked allele |
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61. Genetic maps are based on recombination frequencies. Because both odd and even numbers of crossovers can occur between any 2 gene loci, as the physical distance between two loci increases, the maximum recombination frequency levels off at 50%. However, suppose you discovered a species where only an even number of crossovers can occur between any two gene loci. In this case, as the physical distance between two loci increases, you would expect the maximum recombination frequency to |
A. remain at zero |