MOCK EXAM 3
1. In a test cross between a homozygous recessive white flower and an unknown purple flower, the cross results in ½ white flowers and ½ purple flowers. What is the genotype of the unknown purple flower?
A. Homozygous dominant
B. Heterozygous
C. Homozygous recessive
D. None of the above
2. A cross between two heterozygous purple flowers results in a ______genotype and a ______phenotype.
A. 1:2:1, 3:4
B. 2:3, 1:4
C. 1:2:1, 3:1
D. 2:1:2, 1:4
3. A true breeding parental crosses result in ______F1 offspring.
A. Heterozygous
B. Homozygous Dominant
C. Homozygous recessive
D. None of the above
4. A di-hybrid cross between 2 yellow round pea plants heterozygous for both seed shape and seed color result in a ______phenotypic ratio?
A. 9:3:4
B. 3:1
C. 9:3:3:1
D. 1:2:1
5. A botanist breeds a red flower with a white flower and observes that their offspring are white, red, and pink. What sort of dominance does this plant display?
A. Complete dominance
B. Codominance
C. Incomplete Dominance
D. Blending Hypothesis
6. Two Black Labs with the genotype BbEe are mated together. What is the chance that they have a puppy that has a yellow coat?
A. 9/16
B. 3/16
C. 1/4
D. Not a possible coat color
7. Type AB blood possesses ______surface antigens and can receive ______blood.
A. AB/ All blood types
B. A only/ type O
C. B only/ All blood types
D. No/ Only A and B
8. Frizzled chickens possess a single gene that causes them to be resistant to high heat and causes them to have frizzled feathers. This gene is an example of ______.
A. Epistasis
B. Multifactorial gene
C. Pleiotropy
D. Polygenic Inheritance
one gene many traits..
9. Modifiers that control the color of the eye affect ______.
A. Amount of pigment
B. Tone of pigment
C. Where pigment is deposited
D. All of the above
10. John and Katy each have a sibling with Thalassemia, but neither John nor Katy nor any of their parents have the disease. Calculate the probability that if this couple has a child, the child will have Thalassemia.
A. 1/8
B. 1/4
C. 1/9
D. 2/3
11. Using the previous question’s information, what would the probability be if a test revealed that John is a carrier and Katy is not?
A. 1/4
B. 0
C. 2/3
D. 1/9
12. If a plant is heterozygous for 3 traits (complete dominance) is allowed to self fertilize, what proportion of it’s offspring do you expect to be homozygous recessive for all 3 traits?
A. 1/9
B. 1/32
C. 1/64
D. 1/8
13. Newly discovered recessively inherited disease is expressed only in individuals with type O blood, although the disease and blood groups are independently inherited. A normal man with type A blood and a normal woman with type B blood have already had a child with the disease. The woman is now pregnant for a second time. What is the probability that the second child will also have the disease? Assume that both parents are heterozygous for the gene causing the disease.
A. 1/8
B. 1/4
C. 1/32
D.1/16
14. In the ZW system the homogametic sex is ______.
A. the females
B. both sexes
C. the males
D. such a system doesn’t exist.
15. If a male that has Agammaglobulinmia mates with a female that is not a carrier for the same disease, what percentage of their offspring will potentially be carriers?
A. 25%
B. 50%
C. 75%
D. 100%
16. If a female carrier mates with a color-blind male what is the percentage that each child born to them will be color-blind?
A. 25%
B. 50%
C. 75%
D. 100%
17. A mitochondrial disease will be passed on to ______.
A. only males
B. only females
C. males and females equally
D. not heritable
18. The epigenetic silencing observed in Prater-Willi and Angelmann’s syndrome is an example of ______.
A. epistasis
B. genomic imprinting
C. translocation
D. deletion
19. The inactivation of an X chromosome is called ______.
A. epistasis
B.Polygenics
C.Lyonization
D. Single X hypothesis
20. A male with ______could be confused with a woman if a scientist looked at a tissue sample.
A. Turner’s Syndrome
B. Triple X
C. XYY
D.Kleinfelter’s Syndrome
21. A di-hybrid grey-bodied normal wing female fly is crossed with a double mutant black body vestigial wing male. The cross yielded,: 30 gray normal, 4 black normal, 40 black-vestigial, and 26 grey vestigial. How many map units are the genes for body color and wing type located from each other?
A. 70 MU
B. 40 MU
C. 30 MU
D. unable to tell from information
22. In a cross between a yellow round pea plant with the genome YyRr and a green wrinkled pea plant with the genome yyrr, what phenotypes represent the recombinants of the cross?
A. Yellow round
B. green round
C. green wrinkled
D. Yellow wrinkled
E. Both B and D
23. Nondisjunction during meiosis 2 results in ______.
A. 2 triploid cells and 2 monosomiccells gametes
B. 2 monosomic cells and 2 diploid cells gametes
C.one triploid one monosomic and 2 diploid gametes
D. the shutdown of meiosis
24. Is non-disjunction in Meiosis 1 or 2 more dangerous (per say)?
A. Meiosis 1
B. Meiosis 2
C. Mathematically they are equally as dangerous as each other
D. Not enough is known about nondisjunction
25. In which genomic sequence is an inversion present:ABCDE
A.ACDEB
B.ACDE
C.AABCDE
D.ADCBE
26. There are three genes in question: S, A, and T. According to recent experiments it has been determined that T and A share a 12% recombination frequency, S and A share a 6% recombination frequency, and S and T share a 18% recombination frequency. What order are there genes located in in a chromosome?
A. AST
B. STA
C. TAS
D. not enough information to determine
27. By convention, each map unit corresponds to 1% recombination frequency. T or F
28. The amount of individuals that carry a gene that actually express a gene is called ______.
A. modification
B.expressivity
C. penetrance
D. polyploidy
29. What is the percentage of Thymine in a DNA backbone if you know: Adenine = 30.3%, Guanine = 19.5%, and Cytosine = 19.5%.
A. 19.5%
B. 27.7%
C. 30.3%
D. 19.3 %
30. The Hershey chase experiment proved that DNA was the genetic material found in living organisms because radiolabeled 35-S was found inside the bacterial cells. T or F
31. A color-blind man marries a woman with normal vision whose father is color-blind. What is the probability that they will have a colorblind daughter? What is the probability that their first son will be color-blind?
A. 1/4, 1/4
B. 1/2, 1/4
C. 1/4, 1/2
D. 1/3 , 1/4
32. A white-eyed female Drosophila is mater with a red-eyed wild type male. What phenotypes and genotypes do you predict for the offspring?
A. all white eyed females, all red eyed males
B. all red eyed heterozygous females, all white eyed males
C. none of the above
D. both A and B
33. Which of the following is not true of RNA processing?
A. exons are cut out before mRNA leaves the nucleus
B. Nucleotides may be added at both ends of the RNA
C. Ribozymes may function in RNA splicing
D. RNA splicing can be catalyzed by splisosomes
E. A primary transcript is often much longer than the final RNA molecule that leaves the nucleus
34. Which of the following is not true of a codon?
A. it consists of 3 nucleotides
B.it may code for the same AA as another codon
C. it never codes for more than one AA
D. it extends from one end of a tRNA molecule
E. it is the basic unit of genetic code
35. The anticodon of a particular tRNA molecule is
A. complementary to the corresponding mRNA codon
B. complementary to the corresponding rRNA codon
C. the part of the tRNA that bonds to a specific amino acid
D. changeable depending on the AA that attatches to the tRNA
E. catalytic, making the tRNA a ribozyme
36. Which component is NOT directly involved in translation?
A. mRNA
B. DNA
C.tRNA
D. ribosomes
E. GTP
37. In a nucleosome, the DNA is wrapped around
A. polymerase
B. ribosomes
C. histones
D. thymine dimer
E.satelite DNA
38. The repressor protein in an operon system is made by the ______.
A. RNA Polymerase
B. functional genes
C. regulatory genes
D. promoter region
39. In a trp operon system, if excess intracellular tryptophan is high it will bind to the repressor causing the repressor to become ______.
A. activated
B. inactivated
C. bound to the operator
D. unbound from the operator
E. Both A and C
F. Both B and D
40. In the lac operon, bacteria make their repressors in the ______form.
A. inactive
B. unprocessed
C. active
D. depends on if lactose is present
41. In the lac operon, ______binds to CAP. CAP then binds to ______.
A.cAMP, lactose
B. lactose, cAMP
C. lactose, the promoter region
D.cAMP, the promoter region
42. Regulatory genes are found ______the promoter region in an operon system.
A. before (upstream)
B. within
C. after (downstream)
D. all of the above
43. 4. Which of the following matings cannot produce a child with the blood type O? The letter refers to the blood types (phenotypes).
A. O x O
B. O x AB
C. A x A
D. A x B
E. All of the above could produce a child with the blood type O.
44. The pedigree for a particular family is shown below.
Is the trait recessive or dominant? Is the mother of the first generation homozygous or heterozygous?
A. recessive/ homozygous
B. recessive heterozygous
C. dominant/ homozygous
D. dominant/ heterozygous
E. There is not enough information available to answer the question.
45. On a linkage map, eye color and eye shape are 56 map units apart, while eye color and vision are 15 map units apart. Which will have a higher rate of recombinants?
A. Eye color and eye shape
B. Eye color and vision
C. What is a map unit?
D. None of the abovE.
46. Why are individuals with an extra chromosome 21, which causes Down syndrome, more numerous than individuals with an extra chromosome 3 or chromosome 16?
A. Chromosome 21 is a sex chromosome, and 3 and 16 are not.
B. There are probably more genes on chromosome 21 than on the others.
C. Nondisjunction of chromosomes 3 and 16 probably occurs much less frequently.
D. Extra copies of other chromosomes are probably fatal to the developing embryo.
E. Down syndrome is not more common, just more serious.
47. Which of the following enzyme is not correctly paired with its function?
A. Single-strand proteins-keep separated strands of DNA from reconnecting
B. Topoisomerase- helps to relieve the strain off of the rest of the strand of DNA
C. Helicases- rewind the double helix after replication
D. Primase- synthesizes a small RNA segment called a primer
E. All of the above are paired correctly.
48. DNA polymerase adds nucleotides to the ______of the leading strands and to the ______of the lagging strands.
A. 5’ end….. 5’ end
B. 5’ end…… 3’ end
C. 3’ end…… 5’ end
D. 3’ end…… 3’ end
E. sugar group….. Phosphate group
49. What is the basis for the difference in how the leading and lagging strands of DNA molecules are synthesized?
A. DNA ligase works only in the 3’ toe 5’ direction.
B. The origins of replication occur only at the 5’ end.
C. Polymerase can work on only one strand at a time.
D. Helicases and single-strand binding proteins work at the 5’ end.
E. DNA polymerase can join new nucleotides only to the 3’ end of a growing strand.
50. How are Okazaki fragments connected?
A. The nucleotides are in close enough proximity that they form together spontaneously.
B. DNA ligase joins the fragments together.
C. DNA polymerase joins the fragments together as the primer is replaced.
D. The cell heats up during DNA replication to ensure the fragments have enough energy to bond together.
E.The Okazaki fragments don’t have to be connected.
51. Which of the following is true regarding how mistakes are fixed in DNA replication?
A. Nuclease cuts out the faulty DNA sequence.
B. DNA polymerase lays down new DNA to replace the faulty sequence.
C. DNA ligase seals the 3’ end of the new DNA to the 5’ end of the existing DNA.
D. All of the above are true.
E. None of the above are true.
52. Which of the following statements about replication origins is correct?
A. In both prokaryotes and eukaryotes, replication proceeds in both directions from each origin.
B. The two strands of DNA at the origin are separated, allowing the formation of a replication bubble.
C. Bacterial chromosomes have a single origin, but eukaryotic chromosomes have many origins.
D. In eukaryotic cells, the many replication bubbles fuse once replication is complete.
E. All of the above.
53. Which is true regarding the recognized model of DNA replication?
A. The conservative model is recognized.
B. Of the two daughter DNA double-strands one is composed completely of paternal DNA and one is composed completely of new DNA.
C. The semi-conservative model is recognized.
D. In each daughter DNA double-strand, one strand is composed of paternal DNA and the other strand is composed of new DNA.
E. A and B
F. C and D
54. A cell biologist found that two different proteins with largely different structures were translated from two different mRNAs. These mRNAs, however, were transcribed from the same template within the cell nucleus. Which mechanism below could best account for this?
A. A point mutation might have altered the gene.
B. The two proteins have different functions in the cell.
C. Different systems of DNA unpacking could result in two different mRNAs.
D. Exons from the same gene could be spliced in different ways to make different mRNAs.
E. Different transcription factors were involved in the transcription of the two mRNAs.
55. Which of the following is NOT true regarding eukaryotic transcription?
A. The promotor is the location where RNA polymerase binds.
B. The promotor follows the sequence GAGA.
C. Transcription factors are special proteins that help RNA polymerase bind.
D. The promotor, transcription factors, and RNA polymerase form the transcription initiation complex.
E. All of the above are true.
56. What happens directly after a tRNA moves to the P site?
A. It leaves the ribosome.
B. It transfers its growing peptide to the amino acid on the tRNA in the A site.
C. It accepts the growing peptide from the tRNA in the A site.
D. The ribosome breaks apart and protein synthesis ceases.
E. None of the above.
57. Which of the following is NOT true of RNA processing?
A. Nucleotides may be added at both ends of the RNA.
B. A primary transcript is often much longer than the final RNA molecule that leaves the nucleus.
C. RNA splicing can be catalyzed by splicesomes.
D. The poly A tail often assists in helping the mRNA find its way out of the nucleus and to a ribosome.
E. All of the above are true.
58. 3.Most human-infecting viruses are maintained in the human population only. However, a zoonosis is a disease that is transmitted from other vertebrates to humans, at least sporadically, without requiring viral mutation. Which of the following is the best example of a zoonosis?
A.rabies
B.herpesvirus
C.Smallpox
D.HIV
E.Hepatitis virus
59. 4.Which of the following accounts for someone who has had a herpesvirus-mediated cold sore or genital sore getting flare-ups for the rest of his or her life?
A.Re-infection by a closely related herpesvirus of a different strain
B.Re-infection by the same herpesvirus strain
C.Co-infection with an unrelated virus that causes the same symptoms
D.Copies of the herpesvirus genome permanently maintained in host nuclei
E.Copies of the herpesvirus genome permanently maintained in host cell cytoplasm
60.Why do RNA viruses appear to have higher rates of mutation?
A.RNA nucleotides are more unstable than DNA nucleotides.
B.Replication of their genomes does not involve proofreading.
C.RNA viruses replicate faster.
D.RNA viruses can incorporate a variety of nonstandard bases.
E.RNA viruses are more sensitive to mutagens.
Refer to the treatments listed below to answer the following questions (12-14).
You isolate an infectious substance that is capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, viroid, or prion. You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent.
I.Treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectious.
II.Filtering the substance to remove all elements smaller than what can be easily seen under a light microscope
III.Culturing the substance by itself on nutritive medium, away from any plant cells
IV.Treating the sample with proteases that digest all proteins and then determining whether it is still infectious
61.Which treatment could definitively determine whether or not the component is a viroid?
A.I
B.II
C.III
D.IV
E.First II and then III
62.If you already knew that the infectious agent was either bacterial or viral, which treatment would allow you to distinguish between these two possibilities?
A.I
B.II
C.III
D.IV
E.Either II or IV
63.Which treatment would you use to determine if the agent is a prion?
A.I only
B.II only
C.III only
D.IV only
E.Either I or IV
64.Antiviral drugs that have become useful are usually associated with which of the following properties?
A.abilities to remove all viruses from the infected host
B.interference with viral replication
C.prevention of the host from becoming infected
D.removal of viral proteins
E.removal of viral mRNAs