SC214 General Biology II Problem Set #2

12) Which of the following statements is consistent with the assertion that protists are paraphyletic? A) There is no common set of synapomorphies that define a protist. B) Protists all share a common set of synapomorphies. C) Protists are all more primitive than land plants and animals. D)Protists are more closely related to each other than to other groups of eukaryotes.

A

13) According to the phylogenetic tree in the accompanying figure, G. intestinalis constitutes a _______________ group. A) paraphyletic B) monophyletic C) polyphyletic

A

15) Which of the following might be a result of adding a secondary consumer to the aquatic ecosystem in the accompanying illustration? A) A decrease in the number of primary consumers B) A decrease in the population of decomposers C) An increase in atmospheric carbon dioxide D) An increase in the population of scavengers E)A decrease in the carbon sink

A

32) Fungi that absorb nutrients from decaying plant matter are called ____________________. A) saprobes B) mycorrhizae C) mushrooms D) yeasts E)molds

A

4) You need to identify the major type of bacteria living on the shower curtain in your bathroom and find out what they use as a food source. What is the most efficient method for answering this question? A) Enrichment culture B) Producing a molecular phylogeny C) Direct sequencing D)Enrichment culture and direct sequencing are equally efficient methods.

A

21) The major function of medicinal compounds in plants is to____________________ . A) attract pollinators for seed dispersal B) attract insects and birds to spread seeds and fruits C) defend the plant against herbivores D)defend the plant against microbes

C

1) Which of the following traits do archaea and bacteria share? A) Composition of the cell wall B) Lack of a nuclear envelope C) Presence of plasma membrane D) Composition of a cell wall and lack of a nuclear envelope E)Lack of a nuclear envelope and presence of a plasma membrane

E

19) According to the endosymbiotic theory, why was it adaptive for the larger (host) cell to keep the engulfed cell alive, rather than digesting it as food? A) The engulfed cell provided the host cell with adenosine triphosphate (ATP). B) The engulfed cell provided the host cell with carbon dioxide. C) The engulfed cell allowed the host cell to metabolize glucose. D) The host cell was able to survive anaerobic conditions with the engulfed cell alive. E)The host cell would have been poisoned if it had digested the engulfed cell

A

30) Which of the following is an important role for fungi in the carbon cycle? A) Fungi release fixed carbon back to the environment for other plants and photosynthetic organisms to utilize. B) Fungi provide fixed carbon to plants for the production of plant cellular tissues. C) Fungi fix carbon by undergoing photosynthesis. D)Fungi reduce atmospheric carbon dioxide.

A

37) Studies have shown that in some forest ecosystems carbon can move from one tree to another via mycorrhizal fungi. Which of the following features of fungal biology enables this? A) The cells of fungal hyphae are connected by pores that allow passage of cytoplasm from cell to cell. B) Fungal cells have large numbers of transporter proteins for moving digested materials around the mycelia. C) Fungal cells have flagella, which can help with movement of materials. D)Mycorrhizae form symbiotic associations with bacteria that assist with transport.

A

39) It has been hypothesized that fungi and plants have a mutualistic relationship because fungi provide critical nitrogen for the plants' use. How do we know this happens? In experiments using radioactively labeled . A) nitrogen, plants acquired more radioactive nitrogen when they were associated with fungi B) nitrogen, labeled nitrogen showed up in fungi when the fungi were symbiotic with plants C) carbon, plants acquired more radioactive carbon when they were associated with fungi D)proteins, plants transported labeled proteins to adjacent fungi

A

9) You acquire a soil sample and run an enrichment culture on it. You provide the organisms in the culture with all of the ingredients required for growth except for nitrogen. What result do you expect to have at the end of your experiment? A) Nitrogen-fixing bacteria will significantly outnumber those incapable of fixing nitrogen. B) Nitrogen-fixing bacteria will not be present in the culture. C) Nitrogen-fixing bacteria will be present but not at significantly greater numbers than nonnitrogen-fixing species. D)Nitrogen-fixing bacteria will be present, but will be significantly outnumbered by nonnitrogen-fixing species.

A

14) Which of the following statements best describes the term synapomorphy? A) A trait that is shared by more than one monophyletic group B) A trait that evolved in the most recent common ancestor of a monophyletic group C) The state of having several traits in common with different monophyletic groups D)A trait that evolved in several different monophyletic groups simultaneously

B

18) Consider the following points: (a) many excavates live in environments where oxygenavailability is low; (b) many excavates lack mitochondria; and (c) all excavates have some mitochondrial genes. Based on this information, which of the following statements is TRUE of the excavate lineage? A) Their ancestors were eukaryotes that existed prior to the origin of mitochondria. B) Their ancestors had mitochondria, but the mitochondria were lost over time in some lineages. C) Their ancestors were not able to metabolize glucose. D)Excavates are in the process of acquiring mitochondria through evolutionary adaptation.

B

2) What is the goal of bioremediation? A) To improve human health with the help of living organisms such as bacteria B) To clean up areas polluted with toxic compounds by using bacteria C) To improve soil quality for plant growth by using bacteria D) To improve bacteria for production of useful chemicals E)To kill pathogenic bacteria with the use of antibiotics

B

20) In the process of alternation of generations, the __________________________. A) sporophyte is haploid and produces gametes B) sporophyte is diploid and produces spores C) gametophyte is haploid and produces spores D) gametophyte is diploid and produces gametes E)spores unite to form a zygote

B

22) Over human history, which process has been most important in improving the features of plants long used by humans as staple foods? A) Genetic engineering B) Artificial selection C) Natural selection D) Sexual selection E)Pesticide and herbicide application

B

24) The most direct ancestors of land plants were probably _________________. A) kelp (brown alga) that formed large beds near the shorelines B) green algae C) photosynthesizing prokaryotes (cyanobacteria) D)liverworts and mosses

B

3) Some researchers have begun attempting to clean up oil spills by adding nonindigenous microbial hydrocarbon degraders to the spill, in the hope that these bacteria will neutralize the dangerous chemicals in the spill. This is an example of . A) bioremediation via fertilization B) seeding C) production of a new antibiotic D)use of extremophiles for cleanup of organic solvents

B

33) All fungi are _____________. A) symbiotic B) heterotrophic C) flagellated D) pathogenic E)decomposers

B

38) It has been hypothesized that fungi and plants have a mutualistic relationship because plants make sugars available for the fungi's use. What is the best evidence in support of this hypothesis? A) Fungi survive better when they are associated with plants. B) Radioactively labeled sugars produced by plants eventually show up in the fungi with which they are associated. C) Fungi associated with plants have the ability to undergo photosynthesis and produce their own sugars, whereas those not associated with plants do not produce their own sugars. D) Radioactive labeling experiments show that plants pass crucial raw materials to the fungus for manufacturing sugars.

B

40) Some fungal species can kill herbivores while feeding off of sugars from its plant host. What type of relationship does this fungus have with its host? A) Parasitic B) Mutualistic C) Commensal D)Predatory

B

41) Lichens are symbiotic associations of fungi and __________________ . A) mosses or algae B) cyanobacteria or algae C) green algae or liverworts D) mosses or cyanobacteria E)mosses or sponges

B

43) Which of the following supports the argument that viruses are nonliving? A) They lack genetic material. B) They are not cellular. C) Their DNA does not encode proteins. D) They have RNA rather than DNA. E)They do not evolve.

B

44) Viruses _____________________ . A) manufacture their own ATP, proteins, and nucleic acids B) use the host cell to copy themselves and make viral proteins C) use the host cell to copy themselves and then viruses synthesize their own proteins D)metabolize food and produce their own ATP

B

45) When people die from HIV infections, it is usually because they __________. A) have too many HIV particles in their lymphatic system, which causes it to shut down B) have too few T cells to adequately fight infection C) have too many T cells, and this overwhelms their immune systems D)divert too much energy toward replicating the virus

B

47) Which of the following statements does NOT explain the reason populations have been so adversely affected by pandemics such as the influenza pandemic of 1918 or the current AIDs pandemic? A) There have been no effective vaccines developed for these two viruses. B) Both viruses are very virulent and kill their hosts very rapidly. C) There was no cure for individuals infected with these viruses. D) The immune system could not keep up with the multiplication and spread of the influenza virus in the host cells. E)The immune system was targeted and slowly destroyed by the HIV I virus.

B

48) HIV is inactivated in the laboratory after a few minutes of sitting at room temperature, but the flu virus is still active after sitting for several hours. What are the practical consequences of these findings? A) HIV can be transmitted more easily from person to person than the flu virus. B) The flu virus can be transmitted more easily from person to person than HIV. C) This property of HIV makes it more likely to be a pandemic than the flu virus. D)Disinfecting surfaces are more important to reduce the spread of HIV than of the flu.

B

50) What is the function of reverse transcriptase in retroviruses? A) It hydrolyzes the host cell's DNA. B) It uses viral RNA as a template for DNA synthesis. C) It converts host cell RNA into viral DNA. D) It translates viral RNA into proteins. E)It uses viral RNA as a template for making complementary RNA strands.

B

53) Poliovirus is an RNA virus of the picornavirus group, which uses its RNA as mRNA. At its 5' end, the RNA genome has a viral protein (VPg) instead of a 5' cap. This is followed by a nontranslated leader sequence, and then a single long protein-coding region (~7000 nucleotides), followed by a poly-A tail. Observations were made that used radioactive amino acid analogues. Short period use of the radioactive amino acids results in labeling of only very long proteins, while longer periods of labeling result in several different short polypeptides. What conclusion is most consistent with the results of the radioactive labeling experiment? A) Host-cell ribosomes only translate the viral code into short polypeptides. B) The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones. C) The RNA is translated into short polypeptides, which are subsequently assembled into large ones. D)The large radioactive polypeptides are coded by the host, whereas the short ones are coded for by the virus.

B

55) Viruses use the host's machinery to make copies of themselves. However, some human viruses require a type of replication that humans do not normally have. For example, humans normally do not have the ability to convert RNA into DNA. How can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires? A) The virus causes mutations in the human cells, resulting in the formation of new enzymes that can perform these roles. B) The viral genome has genes coding for enzymes needed for its own reproduction. C) The virus infects only those cells and species that can perform all the replication roles necessary. D)Viruses can stay in a quiescent state until the host cell evolves this ability.

B

Use the following information to answer the question below. Harold and Kumar are premed and pre-pharmacy students, respectively. They complain to their biology professor that they should not have to study about plants because plants have little relevance to their chosen professions. 28) Which adaptations of land plants are likely to provide Harold with future patients? I. Sporophyte dominance II. Defenses against herbivory III. Adaptations related to wind dispersal of pollen A) I and II B) II and III C) I and III D)I, II, and III

B

11) Protists and bacteria are grouped into different domains because . A) protists eat bacteria B) bacteria are not made of cells C) protists have a membrane-bounded nucleus, which bacterial cells lack D) bacteria decompose protists E)protists are photosynthetic

C

17) A particular species of protist has obtained a chloroplast via secondary endosymbiosis. You know this because the chloroplasts ________________. A) have nuclear and cyanobacterial genes B) are exceptionally small C) have three or four membranes D)have only a single pigmen

C

26) Which of the following was a challenge to the survival of the first land plants? A) Too much sunlight B) A shortage of carbon dioxide C) Desiccation D)Animal predation

C

27) Angiosperms are the most successful terrestrial plants. Which of the following features is unique to them and helps account for their success? A) Wind pollination B) Dominant gametophytes C) Fruits enclosing seeds D) Embryos enclosed within seed coats E)Sperm cells without flagella

C

31) When pathogenic fungi are found growing on the roots of grape vines, grape farmers sometimes respond by covering the ground around their vines with plastic sheeting and pumping a gaseous fungicide into the soil. The most important concern of grape farmers who engage in this practice should be that the _______________________ . A) fungicide might also kill the native yeasts residing on the surfaces of the grapes B) lichens growing on the vines' branches are not harmed C) fungicide might also kill mycorrhizae D)sheeting is transparent so that photosynthesis can continue

C

35) Why is it more difficult to treat fungal infections than bacterial infections in humans? A) Fungi are larger organisms than bacteria and thus require stronger drugs to stop an infection. B) Most fungi are multicellular and thus the drugs required to treat a fungal infection must be able to kill several types of cells; bacteria, on the other hand, are unicellular and thus simpler to kill. C) Fungal and animal cells and proteins are similar. Thus, drugs that disrupt fungal cell or protein function may also disrupt human cell or protein function. D) Fungi are able to mutate more quickly than bacteria, so they quickly develop resistance to antifungal drugs.

C

36) You are a forester charged with increasing productivity in a South American forest newly planted with pines from Oregon. You believe that the southern forest lacks the fungal diversity needed by the North American pines and that this lack of fungi is affecting the pines' productivity, but you have no evidence to support your ideas. Which of the following would be the best approach to assess the diversity of fungi likely contributing to tree productivity in the Oregon forest? A) Count the number of fungal species visible on the leaves of one tree species and then multiply by the number of trees in the forest. B) Collect all the fruiting structures (mushrooms, morels, etc.) found aboveground. C) Do direct sequencing on representative soil samples from across the forest. D) Expose the trees to radiolabeled phosphorus and then collect the soil samples with the greatest radioactivity and do direct sequencing.

C

42) Which of the following best describes the physical relationship of the partners involved in lichens? A) Fungal cells are enclosed within algal cells. B) Lichen cells are enclosed within fungal cells. C) Photosynthetic cells are surrounded by fungal hyphae. D) The fungi grow on rocks and trees and are covered by algae. E)Algal cells and fungal cells mix together without any apparent structure.

C

6) Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in . A) their sources of energy B) their electron acceptors C) their mode of nutrition D)the way that they generate

C

Use the accompanying figure and information to answer the question(s) below. Cells were infected with approximately 1000 copies of either virus A or virus B at the 0 time point. At 5-minute intervals, a sample of the virus and cell mixture was removed. The intact cells were removed from the sample, and the number of viruses per milliliter of culture was determined. 54) Using the data in the figure, how long does it take for virus A to go through one lytic cycle? A) 15 minutes B) 30 minutes C) 45 minutes D)90 minutes

C

Use the following information to answer the question below. The mechanism of cell crawling in protist species is not well defined. Pseudopodia extension involves interactions between actin and myosin (the same molecules that are involved in vertebrate muscle contraction). However, prior to the study described below, no one had provided convincing data that actin and myosin were actually involved in cell crawling in protists. Anatomical studies had identified the cytoskeletal protein actin just below the surface of the cell membrane in several species of protist, but physiological studies had failed to show a functional link among actin, myosin, and cell crawling.In a study by N. Poulsen et al. (Diatom gliding is the result of an actin-myosin motility system, Cell Motility and the Cytoskeleton 44 [1999]: 23-22), researchers tested whether motility in a particular species of diatom involves interactions between actin and myosin. 16) Refer to the study by Poulsen et al. and the accompanying figure. Latrunculin A is a reversible toxin that disrupts the formation of actin fibers. A culture of a particular species of diatom was treated with this toxin diluted in a buffer, while another culture was treated only with the buffer (no toxin; control). The motility of cells in each culture was assessed by counting the number of cells that were moving during a defined period of time. Which of the following conclusions is reasonable based on the figure? A) Formation of actin fibers is not necessary for the movement in this species of diatom. B) The buffer alone largely inhibited movement in this species of diatom. C) In this species of diatom, fully formed actin fibers are necessary for movement. Answer: C

C

46) What is the difference between an epidemic and a pandemic? A) An epidemic is a disease that spreads or becomes more common; a pandemic is a disease that remains stable in terms of numbers affected. B) An epidemic is a disease; a pandemic is a treatment. C) An epidemic is restricted to a local region; a pandemic is global. D) An epidemic has low mortality; a pandemic has higher mortality. E)An epidemic is caused by a bacterial infection; a pandemic is caused by a viral infection.

C

49) A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day, this mixture is sprayed on tobacco plants. We expect that the plants would _________________ . A) develop some but not all of the symptoms of the TMV infection B) develop symptoms typically produced by viroids C) develop the typical symptoms of TMV infection D) not show any disease symptoms E) become infected, but the sap from these plants would be unable to infect other plants Answer: C

C

51) Some viruses can be crystallized and their structures analyzed. One such virus is yellow mottle virus, which infects beans. This virus has a single-stranded RNA genome containing about 6300 nucleotides. Its capsid is 25—30 nm in diameter and contains 180 identical capsomeres. If the yellow mottle virus begins its infection of a cell by using its genome as mRNA, which of the following would you expect to be able to measure? A) Replication rate B) Transcription rate C) Translation rate D) Accumulation of new ribosomes E)Formation of new transcription factors

C

56) You are a physician, and you suspect your patient has a viral infection that has never been seen in humans. The infection is localized in the cells along the lining of the small intestine. The cells in this area are regularly sloughed off and replaced with new cells; that is, these cells are constantly dividing. When you isolate this new virus and incubate it in culture, you discover that it does not replicate well in cultures that have slowly dividing cells, but it does much more damage in cultures that have actively dividing cells. What do these findings suggest about this new virus? A) It is a double-stranded RNA virus. B) It is a negative-sense, single-stranded RNA virus. C) It is a double-stranded DNA virus. D)It is a single-stranded DNA virus.

C

57) In the accompanying figure, at the arrow marked II, what enzyme(s) is (are) being utilized? A) Reverse transcriptase B) Viral DNA polymerase C) Host cell DNA polymerase D) Host cell RNA polymerase E)Host cell DNA and RNA polymerases

C

25) Why are seedless vascular plants considered paraphyletic rather than monophyletic? A) Some of the groups within the seedless vascular plants are more closely related to each other than to other groups (such as Lycophyta). B) They share a more recent common ancestor with seeded plants than they do with the nonvascular plants. C) All of the groups contained within the seedless vascular plants do not have the same ancestor. D)The group includes their common ancestor but also the seeded descendants of that same ancestor.

D

34) Which of the following is major characteristic of fungi that distinguishes them from other eukaryotes? A) Acquiring nutrition through ingestion B) Sessile lifestyle C) Cells with nuclei and mitochondria D) Nutrient acquisition via external digestion E)Decomposition of dead organisms

D

5) Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains? A) Microscopic examination of staining characteristics of the cell wall B) Metabolic characteristics such as the production of methane gas C) Metabolic characteristics such as chemoautotrophy and photosynthesis D) Genetic characteristics such as ribosomal RNA sequences E)Ecological characteristics such as the ability to survive in extreme environments

D

8) A biologist trying to determine the mechanism of adenosine triphosphate (ATP) production in a newly discovered bacterium provides several different substrates on which the bacteria can feed. Which of the following results would indicate that the species uses fermentation to produce ATP? A) The bacteria utilize glucose and produce carbon dioxide as a by-product of respiration. B) After the bacteria break down their substrate, the biologist notices a rotten egg smell. C) The biologist discovers that the bacteria are able to produce organic molecules by metabolizing methane. D)After exposure to amino acids, the bacteria produce a smell like rotting flesh.

D

Researchers tested nitrogen loss from soil where the moss Dawsonia was growing and compared it to soil from which Dawsonia had been removed. The data are presented in the accompanying figure. Researchers decided to test the hypothesis that if the 20-cm-tall Dawsonia acts as a physical buffer, then it would reduce water's ability to erode the soil and carry away its nitrogen. They began with four equal-sized areas where Dawsonia mosses grew to a height of 20 cm above the soil surface. One of the four areas was not modified. In the second area, the mosses were trimmed to a height of 10 cm above the soil surface. In the third area, the mosses were trimmed to a height of 5 cm above the soil surface. In the fourth area, the mosses were trimmed all the way to the ground, leaving only the rhizoids. Water, simulating rainfall, was then added in a controlled fashion to all plots over the course of 1 year. The accompanying figure presents four graphs depicting potential results of this experiment. 23) In the figure, which graph of soil nitrogen loss over time most strongly supports the hypothesis that if the 20-cm-tall Dawsonia acts as a physical buffer, then it reduces water's ability to erode the soil and carry away its nitrogen? A) A B) B C) C D) D E)None of these graphs support the hypothesis.

D

Use the following information to answer the question below. The herpes viruses are important enveloped DNA viruses that cause disease in vertebrates and in some invertebrates such as oysters. Some of the human forms are herpes simplex virus (HSV) types I and II, causing facial and genital lesions, and the varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three actively infects nervous tissue. Primary infections are fairly mild, but the virus is not then cleared from the host; rather, viral genomes are maintained in cells in a latent phase. The virus can later reactivate, replicate again, and infect others. 52) In electron micrographs of HSV infection, the intact virus initially reacts with cell-surface proteoglycans, then with specific receptors. This is later followed by viral capsids docking with nuclear pores. Afterward, the capsids go from being full to being "empty." Which of the following best fits these observations? A) Viral capsids are needed for the cell to become infected; only the capsids enter the nucleus. B) The viral envelope is not required for infectivity, since the envelope does not enter the nucleus. C) Only the genetic material of the virus is involved in the cell's infectivity and is injected like the genome of a phage. D) The viral envelope mediates entry into the cell, the capsid mediates entry into the nuclear membrane, and the genome is all that enters the nucleus. E)The viral capsid mediates entry into the cell, and only the genomic DNA enters the nucleus, where it may or may not replicate.

D

29) Chemicals, secreted by soil fungi, which inhibit the growth of bacteria are known as___________________________ . A) antibodies B) aflatoxins C) hallucinogens D) antigens E)antibiotics

E

58). Which of the three types of viruses shown in the accompanying figure has a capsid? A) I only B) II only C) III only D) I and II only E)I, II, and III

E

7) A newly discovered organism is found to use sulfide (S2−) for aerobic respiration and carbon dioxide (CO2) from the air as a source of carbon, much like a plant. This organism must be a ___________________. A) photoautotroph B) chemoorganoautotroph C) photoheterotroph D) chemolithotrophic heterotroph E)chemolithoautotroph

E

10) Some of the most useful phylogenetic trees are constructed from the alignment of 16S or 18S ribosomal RNA. What is the advantage of using rRNA over mRNA for the construction of phylogenetic trees? A) There is no advantage per se, rRNA is more commonly used because it was the first method developed. B) Only higher eukaryotes possess rRNA; therefore, phylogenetic trees constructed from these sources are more accurate. C) mRNA transcripts vary greatly, as they are dependent upon the genome of the organism, whereas rRNA is found in all organisms. D)mRNA transcripts are too conserved among organisms and therefore cannot be used to construct phylogenies.

c