1. What Is the Primary Reason Why Viruses Are Not Considered to Be Alive?

Biology 123 SI- Dr. Raut’s Class

Mock Exam Four

1. What is the primary reason why viruses are not considered to be alive? A. They do not have proteins. B. They do not have genetic material. C. They cannot replicate without a host cell. D. Viruses are alive. E. None of the above.

2. Which of the following is NOT true regarding the replication of viruses? A. The lytic cycle involves the lysing of the host cell. B. The lysogenic cycle involves the integration of the viral genome into the host cell’s genome. C. Viruses are considered obligate parasites since they cannot replicate outside of the host cell. D. All viruses undergo both the lytic cycle and the lysogenic cycle. E. All of the above are true regarding viruses.

3. Why are phages useful in treating bacterial infections in humans? A. Because of their host specificity, they only attack bacteria. They do not affect eukaryotic cells. B. Because phages are free to evolve, bacteria are less likely to develop a lasting resistance to them. C. Because of their specificity, a phage can be used that will only infect the pathogenic bacteria, leaving helpful bacteria alone. D. They are not useful, and the practice has been banned in all countries. E. A, B, and C are correct.

4. What composes the viral envelope? A. It is a coat composed of proteins that are coded for in the viral genome. B. It is composed of the host cell’s plasma membrane. C. It is composed of the viral genome. D. There is no such thing as a viral envelope. E. None of the above.

5. Reverse transcription, carried out by retroviruses, is the process by which ______. A. RNA information is copied into DNA. B. DNA is duplicated. C. RNA information is “read” to form a protein molecule. D. Information is copied from a protein molecule into RNA. E. DNA information is copied into RNA.

6. A biologist has collected a pathogen that has been infecting a local frog species. He is testing the pathogen for presence of protein and nucleic acids to determine the identity of the pathogen. Which of the following would be the correct result for a virus, a viroid, and a prion? A. Virus: positive for protein, negative for nucleic acids; viroid: positive for protein, positive for nucleic acids; prion: positive for protein, negative for nucleic acids B. Virus: positive for protein, positive for nucleic acids; viroid: positive for protein, negative for nucleic acids; prion: negative for protein, positive for nucleic acids C. Virus: positive for protein, positive for nucleic acids; viroid: negative for protein, positive for nucleic acids; prion: positive for protein, negative for nucleic acids D. Virus: positive for protein, positive for nucleic acids; viroid: positive for protein, positive for nucleic acids; prion: positive for protein, negative for nucleic acids E. Virus: positive for protein, positive for nucleic acids; viroid: negative for protein, positive for nucleic acids; prion: positive for protein, positive for nucleic acids

7. The coccyx (a.k.a. the tailbone) helps to attach the tail to the body in most animals. However, in humans, it has lost functionality. This is most closely and example of: A. convergent evolution B. a vestigial structure C. homology D. adaptation E. None of the above.

8. Which of the following is an example of convergent evolution? A. Blind cave fish possess remnants of eye structures under their scales. B. Cats and bats have similar skeletal configurations in their forelimbs. C. Dolphins and sharks have a similar fusiform (streamlined) body shape. D. Both gymnosperms and angiosperms produce seeds. E. Human embryos and fish embryos both have pharyngeal pouches.

9. Which of the following is NOT true regarding natural selection? A. In natural selection, individuals with certain heritable traits survive and reproduce at higher rates than other individuals because the traits are fit to the environment. B. Over time, natural selection can increase the match between a species and the environment. C. If an environment changes, or if individuals move to a new environment, natural selection may result in adaptation to these new conditions sometimes giving rise to a new species. D. B and C are both not true. E. A, B, and C are true.

10. A population of zooplankton is exposed to a small number of predator 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? A. The predatory fish will evolve smaller mouths so that they do not drive their prey to extinction. B. The predatory fish will evolve poor eyesight so as to preserve their food supply. C. The zooplankton will become sexually mature at larger sizes. D. Adult zooplankton will start to reach sexual maturity when they are still relatively small. E. All of the above could happen. 11. Darwin proposed that new species evolve from ancestral forms by A. The gradual accumulation of adaptations to changing or different environments. B. The struggle for limited resources. C. The excessive production of offspring. D. The inheritance of acquired adaptations to the environment. E. The accumulation of mutations.

12. Which of the following is a source of genetic variation? A. The formation of new alleles through mutation. B. Rapid reproduction. C. Sexual reproduction. D. B and C E. All of the above.

13. Which of the following is NOT a requirement for Hardy-Weinberg equilibrium? A. No mutations B. No natural selection C. A very large population D. Random mating E. All of the above are requirements for Hardy-Weinberg equilibrium.

14. In a population that is in Hardy-Weinberg equilibrium for two alleles, C and c, 16% of the population show the recessive trait. What percent of the population are heterozygous? A. 84% B. 48% C. 32% D. 54% E. 36%

15. If a population has the following genotype frequencies-- AA = .64, Aa= .32, and aa= .4— what are the allele frequencies? A. A=.8, a= .2 B. A= .64, a= .4 C. A=.32, a=.2 D. A=.16, a=.1 E. None of the above.

16. A small group of aliens from Mars come and land on planet earth. They are now separated from the rest of their species and suffer from severely reduced genetic variation. This is an example of: A. the bottleneck effect B. genetic drift C. the founder effect D. disruptive selection E. C and D

17. Genetic drift is likely to be seen in a population A. that has a high migration rate. B. that has a low mutation rate. C. in which natural selection is occurring. D. that is very small E. for which environmental conditions are changing

18. Sparrows with averaged length wings fare storms better than sparrows with long or short wings. Over time, this would result in: A. Disruptive selection B. Stabilizing selection C. Directional selection D. Sexual selection E. relative fitness

19. True or false: It is believed that eventually natural selection will produce the perfect organism.

20. The males of differet species of fruit fly that live in the same parts of the Hawaiian Islands have different elaborate courtship rituals. What type of reproduction isolation does this represent? A. gametic isolation B. habitat isolation C. temporal isolation D. postzygotic barriers E. behavioral isolation

21. What categorizes a species according to the biological species concept? A. a population or group of populations that have similar phenotypic characteristics B. a population or group of populations in which members are a very close match according to genetic testing C. a population or group of populations with the same number of chromosomes D. a population or group of populations that can interbreed in nature, but do not interbreed with other such groups in nature E. All of the above.

22. For which of the following is the biological species concept least appropriate? A. plants B. animals C. prokaryotes D. fossils E. both c and d

23. Which of the following is a way that sympatric speciation can occur? A. After a new food source is introduced, half of a population of trout begin to feed on the new food source, while the other half continue to feed on the old food source. B. Different members of the species begin to differ in sexual selection. C. A large lake’s water line lowers, forming a land mass separating the two halves of the lake, a species of fish get separated into the two different halves and begin to form two different species in the different environments. D. A and B E. All of the above.

24. Which of the following is an example of a postzygotic barrier? A. Two squirrel species produce an offspring that is very weak and dies at a very young age. B. Two sea urchin species have sperm that are incapable of fertilizing eggs of the other species. C. Of two similar beetle species, one lives in the trees, while the other lives in the ground. D. Of two similar bird species, one mates in the early fall, while the other mates in the early spring. E. None of the above.

25. What is a protocell? A. The first prokaryote. B. The group of macromolecules that are considered to be the important precursors to life. C. A membranous sac with an inside chemistry differing from the chemistry of its surroundings. D. The environment that helped to support the evolution of life. E. None of the above. 26. Which period and description below are incorrectly matched? A. Denovian: Diversification of bony fishes; first tetrapods and insects appear B. Premian: Radiation of reptiles; origin of most present-day groups of insects; extinction of many marine and terrestrial organisms at the end of the period (end of the Paleozoic Era) C. Jurassic: Gymnosperms continue as dominant plants; dinosaurs abundant and diverse D. Cretaceous: Extensive forests of vascular plants form; first seed plants appear; origin of reptiles; amphibians dominant E. All of the above are correctly paired.

27. The products of Hox genes______. A. can cause paedomorphosis B. provide positional information in animal embryos C. control the rate of timing and developmental events D. may cause polyploidy in some plants E. result in heterochrony

28. What were the first replicating molecules? A. Viruses B. Phospholipids C. Proteins D. DNA E. RNA

29. Adaptive radiations are often seen after______. A. sexual selection takes place B. mass extinctions C. major new evolutionary adaptations, such as flight, occur D. bacteria and plants both have flagellated gametes E. B and C

30. Which is the least inclusive grouping below? A. family B. class C. order D. phylum E. kingdom

31. What is the focus of the branch of biology called taxonomy? A. the environment B. genetics C. the classification of life-forms by their similarities and differences D. evolution E. the history of the field of biology

32. True or false: Bacteria often grow in groups called colonies.

33. Which of the following is a shape of a bacteria? A. Spiral B. Rod-shaped C. Spherical D. Hexagon-shaped E. A, B, and C

34. Bacteria that ______tend to have abundant internal membranes. A. are photosynthetic B. are gram-negative C. are pathogenic D. have flagella E. All of the above.

35. Which of the following structure is NOT correctly matched with its function? A. Pili-exchange of genetic material B. Fimbrae-attachment of the bacteria to its surrounding or other cells C. Flagella-provides motility D. plasmids-an extra layer added to the bacterial cell wall E. All of the above are correctly matched.

36. A gram-negative cell wall consists of ______. A. a thick layer of peptidoglycan surrounded by an outer membrane containing lipopolysaccharides B. a thin layer of peptidoglycan surrounded by an outer membrane containing lipopolysaccharides C. peptidoglycan and cellulose D. a thin layer of peptidoglycan surrounded by a capsule E. cholesterol and peptidoglycan