Solutions attached 
1. The DNA of a single eukaryotic chromosome is:
a. not complexed with proteins
b. many small fragments of linear DNAs
c. circular
d. a single double helix.
2. In a normal DNA molecule, is it always true that A = T and G = C?
a. Yes
b. No
3. The position of functional genes in a chromosome is demarked by –
a. three-base sequences called codons
b. histone proteins
c. euchromatin
d. heterochromatin
4. If two chromosomes of a species are the same length and have similar centromeres but are not homologous, what is different about them?
a. They are telomeric chromosomes
b. They contain different genes
c. They divide at different times
d. Chromosome condensation is different
e. They recombine with each other
5. In order to diagnose a tumor type, a cytogeneticist photographs a metaphase cell and then cuts out each chromosome and lines them up so that she can see any abnormalities. This display of metaphase chromosomes is called
a. a karyotype
b. a spread
c. histone coiling
d. a telomere
6. On your microscope slide, you have several metaphase cells. You take some Feulgen stain and add it to your slideparts of the chromosomes you see become densely stained while the remainder is poorly stained. In which of the two areas would you expect there to be the most active genes?
a. the densely stained heterochromatic area
b. the densely stained euchromatic area
c. the poorly stained heterochromatic area
d. the poorly stained euchromatic area
7. Where are genes located in eukaryotic organisms?
a. in the nucleus
b. in chloroplasts
c. in mitochondria
d. in all of the above
8. A careless graduate student, after a sleep-deprived night in the lab, accidentally irradiates her yeast cells, creating a ton of mutants. She thinks this is fortuitous, as she is trying to create a histone-deficient mutant yeast and may have achieved her goal this way.
Do you think she can obtain histone deficient mutants?
a. yes, why not?.
b. No, histone-deficient yeast mutants would be unable to divide and propagate themselves
c. No, histone-deficient mutants would not undergo DNA replication
9. Which of the following is the correct order of increasing levels of chromosome packing (smallest to largest)?
a) Nucleosomes-loops-solenoid-supercoils
b) Solenoid-nucleosomes-loops-supercoils
c) Solenoid-nucleosomes-supercoils-loops
d) Nucleosomes-solenoid-loops-supercoils
e) Solenoid-loops-nucleosomes-supercoils
10. Prokaryotic chromosomes differ from eukaryotic chromosomes in that
a. they are not complexed with histone proteins
b. they are circular
c. they are not organized in a nucleus while eukaryotic chromosomes are
d. all of the above are true
11. Aliens from Planet Xenon have been reading our Genetics textbooks to gain insight into the human species. Unfortunately translation into the alien language has mangled Mendel’s laws. Which of the choices below are not acceptable translations:
a. members of a gene pair do not segregate from each other in somatic cells.
b. gene pairs show equal segregation from each other into the sex cells of an organisms
c. alleles assort independently in somatic cells
d. none of the above are misstated.
12. The horse, Equus caballus, has 32 pairs of chromosomes. The donkey, Equus asinus, has 31 pairs of chromosomes. How many chromosomes would be expected in the somatic tissue of a mule hybrid?
a. 31
b. 32
c. 63
d. 64
e. 62
13. Cyclins regulate the process of cell division. Cells without sufficient levels of cyclins are –
a. in metaphase
b. prevented from dividing
c. normal
14. DNA replication occurs during
a. Interphase G1
b. Interphase S
c. Metaphase
d. prophase
e. telophase
15. Which of the following does not happen in Prophase
a. Chromosomes synapse
b. The nuclear membrane disappears
c. Crossing over occurs
d. Chromosomes attach to spindle fibers
e. Chromatids separate
16. Exchange of genetic material between two homologous chromatids over during what stage of cell division?
a. prophase I of meiosis
b. prophase II of meiosis
c. prophase of mitosis
d. interphase of both meiosis and mitosis
e. metaphase of mitosis
17. In his experiments, Mendel noted that when two traits (flower color and seed shape) were involved in a genetic cross, they were inherited independently of one another. The reason for this is that
a. alleles on the same chromosome separate during the formation of gametes.
b. alleles of the same gene separate during the formation of gametes.
c. genes on different chromosomes separate independently during the formation of gametes.
18. Normal mitosis takes place in a diploid cell of genotype A/a B/b. Which of the following might represent possible daughter cells?
a. A; B
b. a; b
c. A; b
d. a; B
e. A/a B/b
19. Mitosis in ferns occurs
a. In the formation of the sporophyte following fertilization
b. In the formation of the gametophyte generation
c. In both formation of the gametophyte generation and formation of the sporophyte generation
20. The locus for gene A is on chromosome pair number 1. The locus for gene B is on chromosome pair number 5. Which of the following gametes can be produced by an individual who is heterozygous for both traits (AaBb)?
A. Aa
B. Bb
C. Ab
D. AA
E. BB
21. What is the inheritance pattern for the trait indicated below?
a. Dominant
b. Recessive
c. Intermediate or co-dominant
22. In lilies, white flowers (W) are dominant to purple flowers (w). If two plants that are heterozygous for flower color are mated, the offspring might have which genotype?
a. W W
b. W w
c. ww
d. any of the above
e. none of the above
23. Sucrase deficiency is a recessive hereditary disease in humans. People with this deficiency cannot digest disaccharides such as sucrose. In a family of 5 children, one has sucrase deficiency. What are the possible genotypes of the parents?
a. SS and ss
b. SS and Ss
c. Ss and Ss.
d. ss and ss.
24. Huntington's disease is characterized by dementia appearing in middle age. An individual with Huntington's disease marries a person without the disease. Fifty-percent of their children develop the disease. The disease appears in progeny of every generation. Males and females develop the disease in equal numbers. Huntington's disease is -
a. A dominant trait
b. A recessive trait
c. A sex-linked trait
d. Due to polygenic inheritance
e. Caused by environmental factors only.
In corn, the locus for bronze ear color has two alleles, Bz = bronze, bz = tan. The locus for leaf color has two alleles, V = dark green, v = virescent (yellow green). A plant which is heterozygous for both loci is self-pollinated. The cross is diagramed below: Chromosomes are indicated as /.
Bz//bz V//v X Bz//bz V//v
Use this information to answer the following two questions.
25. What proportion of the progeny do you expect to have bronze ear color and dark green leaves?
a. 9/16
b. 3/16
c. 1/16
d. 4/16
e. 7/16
26. What proportion of the progeny will have bronze ear color and virescent leaves?
a. 9/16
b. 3/16
c. 1/16
d. 4/16
e. 7/16
Assume that in the above cross, you actually get the following progeny.
Bronze ear, Dark-green leaf 46
Bronze ear, Yellow-green leaf 2
Tan ear, Dark-green leaf 4
Tan ear, Yellow-green leaf 12.
Perform a chi-square test to determine if this ratio fits the ration that you expected. Work in the space below or on the back of your test
Class Observed Expected O-E (O-E)2 / E
Bronze ear, Dark-green leaf 46 36 10 2.78
Bronze ear, Yellow-green leaf 2 12 10 8.33
Tan ear, Dark-green leaf 4 12 8 5.33
Tan ear, Yellow-green leaf 12 4 8 16
DF=3 32.44
27. Your chi square value (round to nearest whole number) is:
a. Less than 2.0
b. Between 2 and 15
c. Between 16 and 30
d. Between 31 and 45
e. Greater than 45
28. If the results of a chi-square test on a particular set of data show a probability value less than 0.05 (0.01 for example), then the hypothesis of no difference between the observed and expected data set
a. must be rejected.
b. must be accepted.
29. If both parents in a family are heterozygous carriers of a recessive disease and have three children, what is the probability that NONE of their children will be affected with the disease?
a. 1/4
b. 1/2
c. 3/4
d. 1/64
e. 0
30. In addition to ABO blood groups, humans can have a number of other blood types. For the MN blood group, individuals can be blood type M, N or MN. This is an example of
a. codominance
b. genetic anticipation
c. multiple alleles
d. incomplete penetrance
e. variable expression
31. Brittle bone disease is a dominant gene. Individuals with a single dominant allele can be severely affected or only slightly. This is called -
a. codominance d. incomplete penetrance
b. genetic anticipation e. variable expression
c. multiple alleles
32. For any gene with multiple alleles, a diploid organism may have a maximum of ________ alleles for that locus.
a. 1 d. 10
b. 2 e. 100
c. 6
Vanessa has obtained two true-breeding strains of mice, each homozygous for an independently discovered recessive mutation that prevents the formation of hair on the body. The discoverer of one of the mutant strains calls his mutation naked, and the other researcher calls her strain hairless. To determine whether the two mutations are simply alleles for the same gene, Vanessa crosses naked and hairless mice with each other. All the offspring are phenotypically wild-type. After intercrossing these F1 mice, however, Vanessa observes 115 (approximately 9/16) wild-type mice and 85 mutant mice in the F2. Answer the next two questions.
33. Are naked and hairless the same gene?
a. yes b. no
34. Given the observed F2 ratios, which of the following can best explain the naked/hairless phenotype
a. one gene with homozygous recessive lethal
b. two genes with either A or B producing hair
c. two genes with either aa or bb blocking hair production
d. three or more genes
35. Roan color in horses is due to a mixture of white and colored hair. It is a codominant trait (Rn1//Rn2 = roan). The Belgium Register of Horse Breeding was examined to determine the frequency of roan and non-roan foals from roan X roan matings. Roan X roan matings resulted in 122 non-roan foals and 249 roan foals. How can this result be explained?
a. Roan is dominant to non-roan
b. One homozygous class is lethal
c. Epistasis
d. Expressivity
e. Penetrance
36. The distinctive fur pattern of Siamese cats results when genes that are responsible for coat color are influenced by
a. temperature.
b. age.
c. gender.
d. X-inactivation.
e. all of the above
37. A person who is known to have a particular dominant gene does not show the phenotype specified by the gene. This is an example of
a. incomplete dominance.
b. epistasis.
c. incomplete penetrance.
d. phenotype switching.
e. sex reversal.
38. Homozygosity for the yellow coat gene (AyAy) in mice is lethal. The molecular basis for lethality is:
a. A deletion in the adjacent ral structural gene
b. An A→T mutation in the A+ gene
c. A deletion in the A+ gene
d. A mutation in the A+ promoter
39. A man and a woman, both with blood type O, get married and have a baby whose blood type is A. The man claims that he can't be the baby's father and asks for a divorce. The woman, whose genotype is HH ii, insists that the child is his. For her husband to be the father of the baby, his genotype must be
a. HH ii d. Hh ii
b. Hh IA i e. none of the above
c. hh IA i
40. In the model organism Neurospora, several thiamine auxotrophic mutants were recovered (thiA- and thiB-) following irradiation. A haploid fungus that was thiA- was crossed with a haploid that was thiB- The progeny were all auxotrophic for thiamine. Are thiA- and thiB- in the same gene?
a. yes
b. no
c. the data are insufficient to answer this question
41. Which of the following is an example of a genetic mosaic?
a. Calico coat color in cats.
b. Albinism in humans.
c. Anhidrotic ectodermal displasia in humans.
d. both A and C
e. all of the above
42. Examine pedigree A above. How is the trait (black) most likely inherited?
a. autosomal dominant
b. X-linked recessive
c. X-linked dominant
d. autosomal recessive
e. Y-linked (holandric)
43. In the pedigree above, what is the probability that person “1” in generation II is a carrier for the trait?
a. ¼
b. ½
c. ¾
d. 100%
e. 0%
44. A rare dominant trait, when exhibited in men, is transmitted to half their sons and to half their daughters. The gene for this trait is carried:
a. on the X chromosome.
b. on an autosome.
c. on the Y chromosome.
d. in the mitochondria.
e. None of the above.
45. A male is identified with 1 Barr body. What are possible chromosome configurations for him?
a. XXY
b. X-sry X
c. XY
d. A or B are possible
e. B or C are possible
46. Which of the following is a human autosome?
a. chromosome 2
b. X chromosome
c. Y chromosome
d. both b and c
e. all of the above
47. What is the inheritance pattern for the trait shown in the pedigree below?
a. Autosomal dominant
b. Autosomal recessive
c. Sex-linked dominant
d. Sex-linked recessive
e. holandric
48. Mom is a carrier for hemophilia. Dad does not have the disease. What proportion of her male children are expected to have the disease?
a. 25%
b. 50%
c. 75%
d. 100%
49. A fruit fly with the genotype AAAXXY would be phenotypically
a. male.
b. female.
c. intersex
d. super (meta) male
e. super (meta) female.
50. What is the chromosome configuration of the person above
a. XX
b. XXX
c. XXY
d. XO
e. XXXXX
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