1. Viruses Can Vary with Respect to All of the Following Characteristics Except _____

BY 123 Mock Exam 4 (Chp. 19, 22, 23, 24, 25, 26, 27)

1. Viruses can vary with respect to all of the following characteristics except _____.

1. DNA or RNA as the genetic material
2. the absence of metabolic machinery
3. single- or double-stranded nucleic acids
4. the presence or absence of a membranous envelope
5. the type of host cell it can infect

2. Which of the following, if any, may be a component of a virus?

1. single-stranded (ss) RNA
2. protein
3. double-stranded (ds) DNA
4. phospholipid bilayer
5. All of the listed responses are correct.

3. Why are phages useful in treating bacterial infections in humans?

1. Because of their host specificity, they only attack bacteria. They do not affect eukaryotic cells.
2. Because of their specificity, a phage can be used that will only infect the pathogenic bacteria, leaving helpful bacteria alone.
3. Because phages are free to evolve, bacteria are less likely to develop a lasting resistance to them.
4. They are not useful, and the practice has been banned in all countries.
5. The first three answers are correct.

4. In the lytic life cycle of phages _____.

1. the cell typically dies, releasing many copies of the virus
2. the entire phage is taken into the bacterium
3. phage DNA is incorporated into the host cell's genome
4. the viral capsid is assembled according to the genetic information of the bacterium
5. DNA replication is not part of the life cycle

5. Restriction enzymes help defend bacteria against viral infections by _____.

1. cutting viral DNA once it has entered the cell
2. preventing the synthesis of viral capsomeres in the cell
3. preventing entry of the viral DNA into the cell
4. preventing integration of the viral genome into the host chromosome
5. preventing the binding of the virus to the cell surface

6. A prophage is a(n) _____.

1. prion that has been integrated into a bacterial cell's chromosome
2. viral genome that has been incorporated into a bacterial cell's chromosome
3. emerging virus
4. type of retrovirus
5. virus that infects bacteria

7. How do retroviruses, such as HIV, differ from other viruses?

1. They can transcribe a DNA copy from a RNA template.
2. They can reproduce only inside living cells.
3. They contain DNA that is used as a template to make RNA.
4. They contain nucleic acids that code for proteins.
5. They have much simpler reproductive cycles than other RNA viruses.

8. Cancer cells often have protein receptor molecules on their surfaces that differ from those on normal body cells. Given this fact, how might viruses be used to treat cancer?

1. Viruses are pathogenic and will infect the host. This treatment will not work.
2. Viruses sometimes cause cancer. This is a bad idea.
3. Viruses could be used to carry genes exclusively to the normal body cells. These genes could encode proteins that would help destroy the cancer cells.
4. Viruses could be engineered to infect only cancer cells by altering viral surface proteins to recognize only the receptors on cancer cells.
5. Viruses could be engineered to attach to the surface receptors on cancer cells to alert the immune system to the presence of cancer.

9. Prions are _____ that are thought to cause disease by _____.

1. an abnormal type of capsid ... dramatically enhancing the rate of viral infection
2. DNA molecules ... jumping around the genome and mutating genes
3. mutant DNA molecules ... encoding toxic proteins
4. abnormally shaped proteins ... inducing similar but normally shaped proteins in the brain to adopt the abnormal form
5. RNA molecules ... encoding toxic proteins

10. Which of the following is a key observation that must be explained in a unifying theory about life?

1. All living things require oxygen to survive.
2. Many basic characteristics are shared by all living things.
3. Evolution is based on descent with modification.
4. The Earth is very old.
5. Organisms are rarely well-suited to their environments

11. In Darwin's view of descent with modification _____.

1. an organism's traits only affect its own survival
2. natural selection can improve the match between an organism and its environment
3. individuals can evolve
4. environmental changes have no effect on the organisms living in that environment
5. natural selection only operates when an organism needs to evolve

12. During periods of rapid environmental change, what can happen to a species that was well-suited to the former environment?

1. he species may go extinct.
2. Individuals with particular traits that provide an advantage in the new environment will have higher reproductive success.
3. The population may change so much in adapting to the new environment that it is considered a new species.
4. Traits that were favorable in the original environment may be detrimental in the new environment.
5. All of the listed responses are correct.

13. A population of zooplankton is exposed to a small number of predatory fish that feed on the larger-sized (adult) zooplankton. Which of the following predictions would most likely occur based on the principles of natural selection?

1. The predatory fish will evolve smaller mouths so that they do not drive their prey to extinction.
2. The zooplankton will become sexually mature at larger sizes.
3. The predatory fish will evolve poor eyesight so as to preserve their food supply.
4. Adult zooplankton will start to reach sexual maturity when they are still relatively small.
5. The first and the third listed responses are both good predictions.

14. Which of the following must exist in a population before natural selection can act upon that population?

1. genetic variation among individuals
2. variation among individuals caused by environmental factors
3. sexual reproduction
4. Three of the responses are correct.
5. Two of the responses are correct.

15. Of the following anatomical structures, which is homologous to the bones in the wing of a bird?

1. cartilage in the dorsal fin of a shark
2. bones in the hind limb of a kangaroo
3. chitinous struts in the wing of a butterfly
4. bony rays in the tail fin of a flying fish
5. bones in the flipper of a whale

16. Over evolutionary time, many cave-dwelling organisms have lost their eyes. Tapeworms have lost their digestive systems. Whales have lost their hind limbs. How can natural selection account for these losses?

1. Natural selection cannot account for losses, only for innovations.
2. Natural selection accounts for these losses by the principle of use and disuse.
3. Under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.
4. The ancestors of these organisms experienced harmful mutations that forced them to find new habitats that these species had not previously used.

17. What must be true of any organ that is described as vestigial?

1. It must be analogous to some feature in an ancestor.
2. It must be homologous to some feature in an ancestor.
3. It must be both homologous and analogous to some feature in an ancestor.
4. It need be neither homologous nor analogous to some feature in an ancestor.

18. If one wanted to find the largest number of endemic species, one should visit which of the following geological features (assuming each has existed for several millions of years)?

1. an isolated ocean island in the tropics
2. an extensive mountain range
3. amidcontinental grassland with extreme climatic conditions
4. a shallow estuary on a warm-water coast

19. In modern terminology, diversity is understood to be a result of genetic variation. Which of the following is a recognized source of variation for evolution?

1. mistakes in translation of structural genes
2. mistakes in protein folding
3. rampant changes to the dictionary of the genetic code
4. binary fission
5. recombination by crossing over in meiosis

20. A trend toward the decrease in the size of plants on the slopes of mountains as altitudes increase is an example of

1. a cline.
2. a bottleneck.
3. relative fitness.
4. genetic drift.
5. geographic variation

21. Over time, the movement of people on Earth has steadily increased. This has altered the course of human evolution by increasing

1. nonrandom mating.
2. geographic isolation.
3. genetic drift.
4. gene flow

22. During breeding season, one should expect female house finches to prefer to mate with males with the brightest red feathers. Which of the following terms are appropriately applied to this situation?

1. sexual selection
2. mate choice
3. intersexual selection
4. All of the Above
5. A&B

23. Adult male humans generally have deeper voices than do adult female humans, which is the direct result of higher levels of testosterone causing growth of the larynx. If the fossil records of apes and humans alike show a trend toward decreasing larynx size in adult females and increasing larynx size in adult males, then

1. sexual dimorphism was developing over time in these species.
2. intrasexual selection seems to have occurred.
3. stabilizing selection was occurring in these species concerning larynx size.
4. selection was acting more directly upon genotype than upon phenotype

24. Which of the following is most likely to produce an African butterfly species in the wild whose members have one of two strikingly different color patterns?

1. artificial selection
2. directional selection
3. stabilizing selection
4. disruptive selection
5. sexual selection

25. Heterozygote advantage should be most closely linked to which of the following?

1. sexual selection
2. stabilizing selection
3. random selection
4. directional selection
5. disruptive selection

26. Which of the various species concepts distinguishes two species based on the degree of genetic exchange between their gene pools?

1. phylogenetic
2. ecological
3. biological
4. morphological

27. 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?

1. reduced hybrid fertility
2. hybrid breakdown
3. mechanical isolation
4. habitat isolation
5. gametic isolation

28. Two species of frogs belonging to the same genus occasionally mate, but the offspring fail to develop and hatch. What is the mechanism for keeping the two frog species separate?

1. thepostzygotic barrier called hybrid inviability
2. thepostzygotic barrier called hybrid breakdown
3. the prezygotic barrier called hybrid sterility
4. gametic isolation

29. The origin of a new plant species by hybridization, coupled with accidents during nuclear division, is an example of

1. allopatric speciation.
2. sympatric speciation.
3. autopolyploidy.
4. habitat selection.

30. According to the concept of punctuated equilibrium, the "sudden" appearance of a new species in the fossil record means that

1. the species is now extinct.
2. speciation occurred instantaneously.
3. speciation occurred in one generation.
4. speciation occurred rapidly in geologic time.
5. the species will consequently have a relatively short existence, compared with other species.

31. In order for speciation to occur, what must be true?

1. The number of chromosomes in the gene pool must change.
2. Changes to centromere location or chromosome size must occur within the gene pool.
3. Large numbers of genes that affect a single phenotypic trait must change.
4. Large numbers of genes that affect numerous phenotypic traits must change.
5. At least one gene, affecting at least one phenotypic trait, must change.

32. Rocky Mountain juniper (Juniperusscopulorum) and one-seeded juniper (J. monosperma) have overlapping ranges. If pollen grains (which contain sperm cells) from one species are unable to germinate and make pollen tubes on female ovules (which contain egg cells) of the other species, then which of these terms is applicable?

1. behavioral isolation
2. mechanical isolation
3. hybrid breakdown
4. reduced hybrid viability

33. Which of the following is the correct sequence of events in the origin of life?

I. formation of protobionts

II. synthesis of organic monomers

III. synthesis of organic polymers

IV. formation of DNA-based genetic systems

1. I, II, III, IV
2. I, III, II, IV
3. II, III, I, IV
4. II, III, IV, I

34. Which of the following characteristics should have been possessed by the first animals to colonize land?

1. were probably herbivores (ate photosynthesizers)

2. had four appendages

3. had the ability to resist dehydration

4. had lobe-finned fishes as ancestors

5. were invertebrates

1. 3 only
2. 3 and 5
3. 1, 3, and 5
4. 2, 3, and 4
5. 1, 2, 3, and 4

35. An organism has a relatively large number of Hox genes in its genome. Which of the following is true of this organism?

1. These genes are fundamental, and are expressed in all cells of the organism.
2. The organism must have multiple paired appendages along the length of its body.
3. The organism has the genetic potential to have a relatively complex anatomy.
4. Most of its Hox genes owe their existence to gene fusion events.
5. Its Hox genes cooperate to bring about sexual maturity at the proper stage of development.

36. The first genes on Earth were probably

1. DNA produced by reverse transcriptase from abiotically produced RNA.
2. DNA molecules whose information was transcribed to RNA and later translated in polypeptides.
3. auto-catalytic RNA molecules.
4. oligopeptides located within protobionts

37. Which of the following statements provides the strongest evidence that prokaryotes evolved before eukaryotes?

1. Prokaryotic cells lack nuclei.
2. The meteorites that have struck Earth contain fossils only of prokaryotes.
3. Laboratory experiments have produced liposomes abiotically.
4. Liposomes closely resemble prokaryotic cells.
5. The oldest fossilized cells resemble prokaryotes.

38. Bagworm moth caterpillars feed on evergreens and carry a silken case or bag around with them in which they eventually pupate. Adult female bagworm moths are larval in appearance; they lack the wings and other structures of the adult male and instead retain the appearance of a caterpillar even though they are sexually mature and can lay eggs within the bag. This is a good example of

1. allometric growth.
2. paedomorphosis.
3. sympatric speciation.
4. adaptive radiation.
5. changes in homeotic genes.

39. The various taxonomic levels (namely, genera, classes, etc.) of the hierarchical classification system differ from each other on the basis of

1. how widely the organisms assigned to each are distributed throughout the environment.
2. their inclusiveness.
3. the relative genome sizes of the organisms assigned to each.
4. morphological characters that are applicable to all organisms.

40. Which of the following pairs are the best examples of homologous structures?

1. bones in the bat wing and bones in the human forelimb
2. owl wing and hornet wing
3. bat wing and bird wing
4. eyelessness in the Australian mole and eyelessness in the North American mole

41. When using a cladistic approach to systematics, which of the following is considered most important for classification?

1. shared primitive characters
2. analogous primitive characters
3. shared derived characters
4. the number of homoplasies
5. overall phenotypic similarity

42. The reason that paralogous genes can diverge from each other within the same gene pool, whereas orthologous genes diverge only after gene pools are isolated from each other, is that

1. having multiple copies of genes is essential for the occurrence of sympatric speciation in the wild.
2. paralogous genes can occur only in diploid species; thus, they are absent from most prokaryotes.
3. polyploidy is a necessary precondition for the occurrence of sympatric speciation in the wild.
4. having an extra copy of a gene permits modifications to the copy without loss of the original gene product

43. Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology?

1. Dogs and wolves have very similar morphologies.
2. Dogs and wolves belong to the same order.
3. Dogs and wolves are both members of the order Carnivora.
4. Dogs and wolves shared a common ancestor very recently

44. The typical prokaryotic flagellum features

1. an internal 9 + 2 pattern of microtubules.
2. an external covering provided by the plasma membrane.
3. a complex "motor" embedded in the cell wall and plasma membrane.
4. a basal body that is similar in structure to the cell's centrioles.
5. a membrane-enclosed organelle with motor proteins.

45. Which statement about the genomes of prokaryotes is correct?

1. Prokaryotic genomes are diploid throughout most of the cell cycle.
2. Prokaryotic chromosomes are sometimes called plasmids.
3. Prokaryotic cells have multiple chromosomes, "packed" with a relatively large amount of protein.
4. The prokaryotic chromosome is not contained within a nucleus but, rather, is found at the nucleolus.
5. Prokaryotic genomes are composed of circular DNA

46. Although not present in all bacteria, this cell covering often enables cells that possess it to resist the defenses of host organisms, especially their phagocytic cells.

1. endospore
2. sex pilus
3. cell wall
4. capsule

47. Prokaryotes' essential genetic information is located in the

1. nucleolus.
2. nucleoid.
3. nucleosome.
4. plasmids.
5. exospore.

48. Which of the following is least associated with the others?

1. horizontal gene transfer
2. genetic recombination
3. conjugation
4. transformation
5. binary fission

49. Regarding prokaryotic genetics, which statement is correct?

1. Crossing over during prophase I introduces some genetic variation.
2. Prokaryotes feature the union of haploid gametes, as do eukaryotes.
3. Prokaryotes exchange some of their genes by conjugation, the union of haploid gametes, and transduction.
4. Mutation is a primary source of variation in prokaryote populations.
5. Prokaryotes skip sexual life cycles because their life cycle is too short

50. Hershey and Chase performed an elegant experiment that convinced most biologists that DNA, rather than protein, was the genetic material. This experiment subjected bacteria to the same gene transfer mechanism as occurs in

1. transduction.
2. transformation.
3. conjugation.
4. binary fission.
5. endosymbiosis.