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Honors Biology Final Exam Study Guide

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SHORT ANSWER
1. Diagram 2 Sample answer: in diagram 2, there are two cell divisions, so this process is meiosis. In diagram 1, there is only one cell division.
2. Mitosis. Sample answer: Mitosis and meiosis are different because meiosis involves two cell divisions.
3. I (Also accept anaphase II.)
4. J. Sample answer: The cells in part J of the diagram have fewer chromosomes. The cells in part D of the diagram have more chromosomes.
5. Sample answer: Homologous chromosomes line up randomly along the equator of the cell. Two chromosomes, one from the mother and one from the father, go to each new cell. So, each cell has one of four possible chromosome combinations.
6. testcross
7. ff
8. Ff
9. Ff. Sample answer: The offspring include both heterozygous and homozygous recessive organisms. Since the offspring get one recessive allele from the white-flowered parent, the other parent must be able to donate either a dominant or a recessive allele.
10. All of the offspring would have the same phenotype. They would all be purple.
11. C2C2
12. pink
13. Parents are C1C1 and C2C2; all offspring are C1C2.
14. 1 = C1C1, 2 = C1C2, 3 = C1C2, 4 = C2C2; incomplete dominance

15. Codominance. The phenotypes of both parents are expressed fully and separately in the offspring.


16. a pedigree chart
17. individuals with a given phenotype
18. The phenotype is caused by a dominant allele because the father has genotype ww and does not have the phenotype. Additionally, the mother has genotype Ww and has the phenotype.
19. There are more females than males with the phenotype. When a gene is sex-linked, there will be more males than females with the phenotype.
20. Students should draw Punnett square with W/w at the the top and w/w at the left side; resulting offspring Ww, Ww, ww, ww


21. translation
22. tRNA
23. 4
24. 5; the small ribosomal unit binds to mRNA in the cytoplasm. The binding attracts a tRNA with methionine to the start codon.
25. When the ribosome encountered a stop codon, the peptide strand would be released and the ribosome would fall apart.
26. frameshift mutation, insertion
27. Sample answer: The reading frame is thrown off because all of the nucleotides are shifted to the right.
28. Sample answer: The resulting protein could have a different amino acid sequence and, as a result, a different shape.
29. Sample answer: no, because body cells do not give rise to gametes, so the mutation would not be passed on.
30. Yes, the human body has DNA repair enzymes that help find and fix mutations.
31. DNA fingerprints for three people
32. This technology is used to identify people at the molecular level.
33. Each band represents the size of DNA fragments, which depends on the number of repeating nucleotide sequences.
34. Yes. Sample answer: The DNA fingerprint for person 3 looks like a combination of the other two DNA fingerprints.
35. Sample answers: DNA fingerprints can be used to study biodiversity, locate GM crops, and identify species and their evolutionary relationships.
36. Plasmid; plasmids are tiny rings of DNA found in bacteria.
37. Restriction enzymes are used to cut out a foreign gene and to cut a plasmid so that each structure has complementary sticky ends.
38. recombinant DNA
39. Transgenic refers to an organism that has one or more genes from another organism inserted into its genome. Sample answer: The recombinant DNA is put into bacteria. Then the bacteria are used to infect plants. The recombinant DNA becomes part of the plant's DNA, and the plant is then transgenic.
40. Transgenic plants are used to increase crop yield. Transgenic crops can be made to be more resistant to frost, disease, and insects.
41. homologous structures
42. Structure A is a human arm, which is used for lifting and carrying items. Structure B is the fin of a whale and is used for swimming. Structure C is the wing of a bat and is used for flying.
43. They share a common ancestor.
44. the wing of a flying insect
45. The three forelimbs are adapted for different functions, but they are formed from similar bones. All three forelimbs have a similar structure. This indicates that the organisms share a common ancestor.


46. the lamprey


47. the Rhesus monkey
48. After the lamprey, the frog's hemoglobin shares the fewest amino acids with that of humans.
49. The Rhesus monkey and humans have the most similar amino acids in the hemoglobin protein. This shows that they share a more recent common ancestor than the other organisms do.
50. Humans and lampreys; this is because they have the greatest difference in the amino acids of the hemoglobin protein.
51. They eat cacti with fewer spines more often.
52. From about 90 spines to about 110 spines.
53. The mean number of spines on each cactus has shifted to the right, or toward a higher number of spines.
54. The wild pigs prefer to eat cactus plants that have fewer spines, so more cacti that are very spiny are surviving to reproduce. Their offspring are also very spiny.
55. directional selection
56. mass extinctions

57. between four and five families per million years


58. between 400 and 600 million years ago (Also allow: about 500 million years ago; about 480 million years ago.)
59. The background rate is more than four families per million years; the highest rate is about 19 families per million years.
60. During a mass extinction many species are wiped out. One well-adapted species can diversify and evolve to live in a wide range of environments that were left empty by all the extinct species. This is called adaptive radiation.
61. Precambrian time
62. Quaternary period
63. The largest mass extinction event divided the Paleozoic and the Mesozoic eras. (Also accept: the Permian and the Triassic periods.)
64. the Cenozoic era
65. Cambrian period, Ordovician period, Silurian period, Devonian period, Carboniferous period, Permian period
66. Australopithecus afarensis
67. Homo neanderthalensis and Homo sapiens; or, Australopithecus afarensis and Homo habilis.
68. Homo brain size and shape more closely resembled those of modern humans.
69. Homo habilis. Stone tools were found alongside these skeletons.
70. Homo sapiens
71. according to their physical and structural similarities
72. the bear
73. Each level is included in all of the more general levels above it.
74. kingdom, phylum, and class
75. the wolf, dog, and bear
76. Accept either of the following answers: they are prokaryotes (or cells without nuclei); they are single-celled organisms.
77. Eukarya
78. Protista
79.

Plantae and Animalia


80. Both the Linnaean system and this chart include the kingdom level. However, the Linnaean system did not include domains, and originally included only two kingdoms.
ESSAY
81. - 1 credit for identifying two of the following: pedigree chart, karyotyping, gene linkage map, chromosome mapping

- 1 credit for describing each method and for explaining that the human genome is so large that any one method is insufficient. Several of the methods are tedious, time-consuming, and inefficient. None gives a comprehensive picture of the human genome.


82. - 1 credit for defining a bacteriophage as a virus that infects bacteria and for identifying it as a good choice for the experiment because it contains little more than DNA and protein

- 1 credit for describing the procedure as follows: 1) Phages with radioactive sulfur atoms in their protein molecules were used to infect bacteria. No radioactivity was found inside the bacteria. 2) Phages with radioactive phosphorus atoms in their DNA molecules were used to infect bacteria. Radioactivity was found inside the bacteria.

- 1 credit for concluding that because phosphorus entered the bacteria, but sulfur did not, the bacteriophages' DNA entered the bacteria, and the protein did not. So, the scientists reasoned that the transforming principle was DNA.
83. - 1 credit for defining a clone as a genetically identical copy of a gene or of an organism

- 1 credit for identifying one potential opportunity for treating disease made possible by cloning. Acceptable answers include, but are not limited to, cloning of organs for transplants or cloning healthy genes to be used in gene therapy.

- 1 credit for predicting that cloning could help save an endangered species by increasing its population. However, people fear that cloning might also reduce biodiversity.

84. - 1 credit for defining natural selection as the mechanism by which individuals that have inherited traits that better suit the environment will survive and produce more offspring

- 1 credit for describing the four main principles of natural selection as variation, overproduction, adaptation, and descent with modification. Variations are the heritable differences that exist in a population and adaptations are the variations that allow an individual to survive better in an environment. Overproduction, which is having many offspring, increases the chance that some will survive. Descent with modification states that over time, as beneficial traits are passed down, more individuals will have those traits in every following generation.

- 1 credit for predicting that individual deer that have difficulty eating food other than the shrubs killed by the drought will die out. Larger deer that are able to reach the leaves of taller trees will survive better and reproduce more offspring.


85. - 1 credit for defining three of the following four factors: gene flow as the movement of alleles from one population to another, genetic drift as the changes in allele frequencies in a population due to chance, sexual selection as occurring when certain traits increase mating success, and mutation as the formation of new alleles.

- 1 credit for explaining that gene flow increases genetic variation; genetic drift reduces genetic variation; sexual selection favors traits that increase mating success; mating introduces new alleles to the gene pool

- 1 credit for examples for three of the following four factors: gene flow, genetic drift, sexual selection, and mutation. Sample answers: gene flow among two populations of ground squirrels when a few individuals move from one population to the other; genetic drift (bottleneck effect) caused by a disease that kills 90 percent of a population of tigers; male bighorn sheep butting heads to compete for females; a mutation that results in an allele associated with a new fur color in foxes.
86. - 1 credit for identifying the five conditions required for Hardy-Weinberg equilibrium as very large populations, no gene flow, no mutations, random mating, and no natural selection

- 1 credit for correctly explaining that populations that meet all the conditions are not evolving and that populations that do not meet all the conditions are evolving


87. - 1 credit for correctly identifying the process as permineralization and sedimentary rock as the type in which most permineralized fossils are found

- 1 credit for describing the most likely environments for fossilization as near or in bodies of water, such as oceans, lakes, bogs, rivers, flood plains, river deltas, and wetlands

- 1 credit for correctly describing circumstances of death needed for fossilization as organisms dying near or in water or in an area of continuous sedimentation; or undergoing rapid burial
88. - 1 credit for explaining the premise as the more time that has passed since two species diverged from a common ancestor, the more mutations will have built up in each lineage

- 1 credit for describing how scientists can connect geological events known to have separated two species with the mutations that happened after the two species diverged from their common ancestor. Fossil evidence can reveal the first appearance of a given species.



- 1 credit for explaining that any physical characteristic passed down from one generation to another will have a genetic basis. The more similar the genes between two species, the closer their relationship is likely to be.


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