Final Exam (S2) Honors Biology

1. Final Exam (S2) Honors Biology Ms. Phillips 2013-2014

2. Which of the following is a true statement about sexual vs. asexual reproduction? • Asexual reproduction, but not sexual reproduction, is characteristic of plants and fungi. • In sexual reproduction, individuals transmit 50% of their genes to each of their offspring. • In asexual reproduction, offspring are produced by fertilization without meiosis. • Sexual reproduction requires that parents be diploid. • Asexual reproduction produces only haploid offspring.

3. If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants? • Backtrack through her previous experiments to obtain another plant with the same traits. • Breed this plant with another plant with much weaker traits. • Clone the plant asexually to produce an identical one. • Force the plant to self-pollinate to obtain an identical one. • Add nitrogen to the soil of the offspring of this plant so the desired traits continue.

4. The human genome is minimally contained in which of the following? • every human cell • each human chromosome • the entire DNA of a single human • the entire human population • each human gene

5. In the human species, all somatic cells have 46 chromosomes. Which of the following can also be true? • A plant species (privet shrubs) has 46 chromosomes per cell. • Some adult humans have 69 chromosomes per cell. • Some adult humans have 23 chromosomes per cell. • A certain fungal species has only one chromosome per cell. • A certain bacterial species has 23 chromosomes

6. Which of the following might result in a human zygote with 45 chromosomes? • Failure of the egg nucleus to be fertilized by the sperm. • Fertilization of a 23 chromosome human egg by a 22 chromosome sperm of a closely related species. • An error in the alignment of chromosomes on the metaphase plate. • Lack of chiasmata in prophase I. • An error in either egg or sperm meiotic anaphase.

7. A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following? • It must be human. • It must be a primate. • It must be an animal. • It must be sexually reproducing. • Its gametes must have 23 chromosomes

8. Which of the following is true of a species that has a chromosome number of 2n = 16? • The species is diploid with 32 chromosomes per cell. • The species has 16 sets of chromosomes per cell. • Each cell has eight homologous pairs. • During the S phase of the cell cycle there will be 32 separate chromosomes. • A gamete from this species has four chromosomes.

9. What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants? • There is considerable genetic variation in garden peas. • Recessive genes occur more frequently in the F1 generation than do dominant ones. • Genes are composed of DNA. • Traits are inherited in discrete units, and are not the results of "blending." • An organism that is homozygous for many recessive traits is at a disadvantage

10. Why did the F1 offspring of Mendel's classic pea cross always look like one of the two parental varieties? • One phenotype was completely dominant over another. • No genes interacted to produce the parental phenotype. • Each allele affected phenotypic expression. • The traits blended together during fertilization. • Different genes interacted to produce the parental phenotype

11. What do we mean when we use the terms monohybrid cross and dihybrid cross? • A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid cross involves only one. • A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents. • A monohybrid cross produces a single progeny, whereas a dihybrid cross produces two progeny. • A monohybrid cross is performed for one generation, whereas a dihybrid cross is performed for two generations. • A monohybrid cross results in a 9:3:3:1 ratio whereas a dihybrid cross gives a 3:1 ratio.

12. When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result? • The gene involved is on the Y chromosome. • The gene involved is on the X chromosome. • The gene involved is on an autosome, but only in males. • Other male-specific factors influence eye color in flies. • Other female-specific factors influence eye color in flies.

13. Sturtevant provided genetic evidence for the existence of four pairs of chromosomes in Drosophila in which of these ways? • Drosophila genes cluster into four distinct groups of linked genes. • There are four major functional classes of genes in Drosophila. • The overall number of genes in Drosophila is a multiple of four. • The entire Drosophila genome has approximately 400 map units. • Drosophila genes have, on average, four different alleles.

14. Which of the following is the meaning of the chromosome theory of inheritance as expressed in the early 20th century? • Individuals inherit particular chromosomes attached to genes. • Mendelian genes are at specific loci on the chromosome and in turn segregate during meiosis. • Homologous chromosomes give rise to some genes and crossover chromosomes to other genes. • No more than a single pair of chromosomes can be found in a healthy normal cell. • Natural selection acts on certain chromosome arrays rather than on genes.

15. Thomas Hunt Morgan's choice of Drosophila melanogaster has been proven to be useful even today. Which of the following has/have continued to make it a most useful species? • I and IV only • II and III only • I, II, and III only • II, III, and IV only • I, II, III, and IV • its four pairs of chromosomes • a very large number of visible as well as biochemically mutant phenotypes • easy and inexpensive maintenance • short generation time and large number of offspring

16. A woman is found to have 47 chromosomes, including three X chromosomes. Which of the following describes her expected phenotype? • masculine characteristics such as facial hair • enlarged genital structures • excessive emotional instability • normal female • sterile female

17. Males are more often affected by sex-linked traits than females because: • males are hemizygous for the X chromosome. • male hormones such as testosterone often alter the effects of mutations on the X chromosome. • female hormones such as estrogen often compensate for the effects of mutations on the X chromosome. • X chromosomes in males generally have more mutations than X chromosomes in females. • mutations on the Y chromosome often worsen the effects of X-linked mutations.

18. SRY is best described in which of the following ways? • a gene present on the X chromosome that triggers female development • an autosomal gene that is required for the expression of genes on the Y chromosome • an autosomal gene that is required for the expression of genes on the X chromosome • a gene required for development, and males or females lacking the gene do not survive past early childhood. • a gene region present on the Y chromosome that triggers male development

19. In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male? • tortoiseshell females; tortoiseshell males • black females; orange males • orange females; orange males • tortoiseshell females; black males • orange females; black males

20. Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents? • XCXcand XCY • XcXcand XcY • XcXc and XCY • XCXC and XcY • XCXC and XCY

21. Calico cats are female because: • the males die during embryonic development. • a male inherits only one of the two X-linked genes controlling hair color. • the Y chromosome has a gene blocking orange coloration. • only females can have Barr bodies. • multiple crossovers on the Y chromosome prevent orange pigment production.

22. In his transformation experiments, what did Griffith observe? • Mutant mice were resistant to bacterial infections. • Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form. • Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains. • Mice infected with a pathogenic strain of bacteria can spread the infection to other mice. • Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic.

23. How do we describe transformation in bacteria? • assimilation of external DNA into a cell • the creation of a strand of DNA from an RNA molecule • the creation of a strand of RNA from a DNA molecule • the infection of cells by a phage DNA molecule • the type of semiconservative replication shown by DNA

24. After mixing a heat-killed, phosphorescent strain of bacteria with a living nonphosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observations would provide the best evidence that the ability to fluoresce is a heritable trait? • DNA passed from the heat-killed strain to the living strain. • Protein passed from the heat-killed strain to the living strain. • The phosphorescence in the living strain is especially bright. • Descendants of the living cells are also phosphorescent. • Both DNA and protein passed from the heat-killed strain to the living strain.

25. Which of the following variations on translation would be most disadvantageous for a cell? • translating polypeptides directly from DNA • using fewer kinds of tRNA • having only one stop codon • lengthening the half-life of mRNA • having a second codon (besides AUG) as a start codon

26. The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following? • A gene from an organism can theoretically be expressed by any other organism. • All organisms have experienced convergent evolution. • DNA was the first genetic material. • The same codons in different organisms translate into the different amino acids. • Different organisms have different numbers of different types of amino acids.

27. Which of the following provides some evidence that RNA probably evolved before DNA? • RNA polymerase uses DNA as a template. • RNA polymerase makes a single-stranded molecule. • RNA polymerase does not require localized unwinding of the DNA. • DNA polymerase uses primer, usually made of RNA. • DNA polymerase has proofreading function.

28. The role of a metabolite that controls a repressible operon is to: • bind to the promoter region and decrease the affinity of RNA polymerase for the promoter. • bind to the operator region and block the attachment of RNA polymerase to the promoter. • increase the production of inactive repressor proteins. • bind to the repressor protein and inactivate it. • bind to the repressor protein and activate it.

29. Which of the following is a protein produced by a regulatory gene? • operon • inducer • promoter • repressor • corepressor

30. Altering patterns of gene expression in prokaryotes would most likely serve the organism's survival in which of the following ways? • organizing gene expression so that genes are expressed in a given order • allowing each gene to be expressed an equal number of times • allowing the organism to adjust to changes in environmental conditions • allowing young organisms to respond differently from more mature organisms • allowing environmental changes to alter the prokaryote's genome

31. In response to chemical signals, prokaryotes can do which of the following? • turn off translation of their mRNA • alter the level of production of various enzymes • increase the number and responsiveness of their ribosomes • inactivate their mRNA molecules • alter the sequence of amino acids in certain proteins

32. Viral envelopes can best be analyzed with which of the following techniques? • transmission electron microscopy • antibodies against specific proteins not found in the host membranes • staining and visualization with the light microscope • use of plaque assays for quantitative measurement of viral titer • immunofluorescent tagging of capsid proteins

33. 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? • Herpes virus • Smallpox • HIV • Hepatitis virus • Rabies

34. Which of the following accounts for someone who has had a herpes virus-mediated cold sore or genital sore getting flare-ups for the rest of his or her life? • re-infection by a closely related herpes virus of a different strain • re-infection by the same herpes virus strain • co-infection with an unrelated virus that causes the same symptoms • copies of the herpes virus genome permanently maintained in host nuclei • copies of the herpes virus genome permanently maintained in host cell cytoplasm

35. How does a bacterial cell protect its own DNA from restriction enzymes? • by adding methyl groups to adenines and cytosines • by using DNA ligase to seal the bacterial DNA into a closed circle • by adding histones to protect the double-stranded DNA • by forming "sticky ends" of bacterial DNA to prevent the enzyme from attaching • by reinforcing the bacterial DNA structure with covalent phosphodiester bonds

36. A principal problem with inserting an unmodified mammalian gene into a BAC, and then getting that gene expressed in bacteria, is that: • prokaryotes use a different genetic code from that of eukaryotes. • bacteria translate polycistronic messages only. • bacterial RNA polymerase cannot make RNA complementary to mammalian DNA. • bacterial DNA is not found in a membrane-bounded nucleus and is therefore incompatible with mammalian DNA. • bacteria cannot remove eukaryotic introns.

37. FA03/S2/20-03 Why are yeast cells frequently used as hosts for cloning? • They easily form colonies. • They can remove exons from mRNA. • They do not have plasmids. • They are eukaryotic cells. • Only yeast cells allow the gene to be cloned.

38. FA03/S2/20-04 Why is it so important to be able to amplify DNA fragments when studying genes? • DNA fragments are too small to use individually. • A gene may represent only a millionth of the cell's DNA. • Restriction enzymes cut DNA into fragments that are too small. • A clone requires multiple copies of each gene per clone. • It is important to have multiple copies of DNA in the case of laboratory error.

39. FA03/S2/21-01 For mapping studies of genomes, most of which were far along before 2000, the three-stage method was often used. Which of the following is the usual order in which the stages were performed, assuming some overlap of the three? • genetic map, sequencing of fragments, physical map • linkage map, physical map, sequencing of fragments • sequencing of entire genome, physical map, genetic map • cytogenetic linkage, sequencing, physical map • physical map, linkage map, sequencing

40. FA03/S2/21-02 What is metagenomics? • genomics as applied to a species that most typifies the average phenotype of its genus • the sequence of one or two representative genes from several species • the sequencing of only the most highly conserved genes in a lineage • sequencing DNA from a group of species from the same ecosystem • genomics as applied to an entire phylum

41. FA03/S2/21-03 What is bioinformatics? • a technique using 3-D images of genes in order to predict how and when they will be expressed • a method that uses very large national and international databases to access and work with sequence information • a software program available from NIH to design genes • a series of search programs that allow a student to identify who in the world is trying to sequence a given species • a procedure that uses software to order DNA sequences in a variety of comparable ways

42. Catastrophism, meaning the regular occurrence of geological or meteorological disturbances (catastrophes), was Cuvier's attempt to explain the existence of • the fossil record. • evolution. • uniformitarianism. • the origin of new species. • natural selection.

43. Charles Darwin was the first person to propose • that evolution occurs. • a mechanism for how evolution occurs. • that Earth is older than a few thousand years. • a mechanism for evolution that was supported by evidence. • that population growth can outpace the growth of food resources

44. Which of these conditions should completely prevent the occurrence of natural selection in a population over time? • All variation between individuals is due only to environmental factors. • The environment is changing at a relatively slow rate. • The population size is large. • The population lives in a habitat where there are no competing species present. • none of the above

45. Natural selection is based on all of the following except • genetic variation exists within populations. • the best-adapted individuals tend to leave the most offspring. • individuals who survive longer tend to leave more offspring than those who die young. • populations tend to produce more individuals than the environment can support. • individuals adapt to their environments and, thereby, evolve.

46. During an individual organism's lifetime, which of these is most likely to help the organism respond properly to changes in its environment? • microevolution • change in allele or gene frequency • change in gene expression • change in average heterozygosity • none of the above

47. Although each of the following has a better chance of influencing gene frequencies in small populations than in large populations, which one most consistently requires a small population as a precondition for its occurrence? • genetic drift • mutation • nonrandom mating • natural selection • gene flow

48. Which of the following is a true statement concerning genetic variation? • It is created by the direct action of natural selection. • It arises in response to changes in the environment. • It tends to be reduced by the processes involved when diploid organisms produce gametes • A population that has a higher average heterozygosity has less genetic variation than one with a lower average heterozygosity. • It must be present in a population before natural selection can act upon the population.

49. Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing • nonrandom mating. • geographic isolation. • genetic drift. • gene flow. • none of the above

50. Dog breeders maintain the purity of breeds by keeping dogs of different breeds apart when they are fertile. This kind of isolation is most similar to which of the following reproductive isolating mechanisms? • reduced hybrid fertility • hybrid breakdown • mechanical isolation • habitat isolation • gametic isolation