answers to tutorials understanding diversity, viruses, bacteria, protista

Understanding Diversity: Systematics


LEARNING OBJECTIVES

After studying this chapter in the text, the student should be able to:

1. State at least two justifications for the use of scientific names and classifications of organisms.

2. Arrange the Linnaean categories in hierarchical fashion, from most inclusive to least inclusive.

3. Describe the three domains and six kingdoms of organisms introduced in this chapter, and give the rationales for and against this system of classification.

4. Based on its distinguishing characters, classify an organism in the appropriate domain and kingdom.

5. Critically summarize the difficulties encountered in choosing taxonomic criteria.

6. Apply the concept of shared derived characteristics to the classification of organisms.

7. Identify methods of molecular biology now used by taxonomists, and summarize the advantages of molecular taxonomy.

8. Contrast monophyletic, paraphyletic, and polyphyletic taxa.

9. Compare and contrast two approaches to systematics: evolutionary systematics and phylogenetic systematics (cladistics).

MULTIPLE CHOICE QUESTIONS

1. Humans depend on other organisms to provide all of the following except:

*A. soil.*B. declining biodiversity.*C. pharmaceuticals.*D. a balance of CO2 and O2 in the atmosphere.*E. recycling of nutrients.

2. The worldwide variety of organisms and ecosystems is termed:

*A. biodiversity.*B. biomixtures.

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*C. ecodiversity.*D. biological multiplicity.*E. organismal diversity.

3. Taxonomy is the science of:

*A. making new biological species.*B. generating cladograms that represent evolutionary relationships

between organisms.*C. naming, describing, and classifying organisms.*D. conserving biodiversity.*E. comparing macromolecules to assess evolutionary relationships.

4. About __________ different species have been described and named to date.

*A. 160,000*B. 265,000*C. 750,000*D. 1.75 million*E. 6.25 million

5. The scientific study of the diversity of organisms and the evolutionary relationships between them is:

*A. taxonomy.*B. ecology.*C. biological classification.*D. evolutionary biology.*E. systematics.

6. What is the correct format for the scientific name of an extinct carnivorous dinosaur?

*A. tyrannosaurus Rex*B. Tyrannosaurus Rex*C. Tyrannosaurus rex*D. Tyrannosaurusrex*E. tyrannosaurus rex

7. The binomial system of nomenclature is a product of the work of:

*A. Charles Darwin.*B. Carolus Linnaeus.

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*C. Gregor Mendel.*D. Paul Hebert.*E. Ernst Haeckel.

8. Which classification level would contain the greatest number of species?

*A. class*B. division or phylum*C. domain*D. family*E. order

9. Which classification level would be the least inclusive?

*A. genus*B. family*C. phylum*D. order*E. class

10.Zea mays is the scientific name of the corn plant. Zea is the ____________ name.

*A. class*B. division*C. genus*D. ordinal*E. species

11.Closely related or similar genera are grouped into a single:

*A. class.*B. phylum.*C. order.*D. species.*E. family.

12.How would the scientific name of the yellow perch, Perca flavescens, be abbreviated?

*A. Perca f.*B. Perca Fl.*C. P. flavescens*D. Perc. fl.

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*E. P. flav.

13.The classification scheme of Linnaeus was originally based on ________, but has now been altered to reflect ___________.

*A. similarities; structural differences*B. biodiversity; structural similarity*C. evolutionary history; structural similarity*D. similarities; evolutionary history*E. differences; similarities

14.Which of the following is a taxon?

*A. class*B. family*C. phylum*D. species*E. All of the above.

15.Some biologists are considering adopting a different classification scheme based on common ancestors, called:

*A. Biodiversity.*B. the biological BarCode.*C. the phylogical guide.*D. the molecular blueprint.*E. PhyloCode.

16.Which of the following is the taxon that can be most clearly defined in biological terms?

*A. class*B. species*C. strain*D. subspecies*E. variety

17.Most biologists recognize ___________ domains.

*A. 3*B. 4*C. 5*D. 6*E. 12

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18.The classification level of domain is immediately "above" (more inclusive than) the level of:

*A. a class.*B. a genus.*C. a kingdom.*D. a phylum.*E. a species.

19.The first kingdom recognized beyond Plantae and Animalia was:

*A. Archae.*B. Protista.*C. Eubacteria.*D. Archaebacteria.*E. Fungi.

20, 21. Use the table to answer the corresponding questions.

Plantae Terrestrial, multicellular, photosynthetic organismsAnthophyta Vascular plants with flowers, fruits, and seedsMonocotyledones

Monocots. Flowering plants with one seed leaf (cotyledon) and flower parts in threes

Commelinales Monocots with reduced flower parts, elongated leaves, and dry 1-seeded fruits

Poaceae Grasses with hollow stems; fruit, a grain; and abundant endosperm in seed

Zea Tall annual grass with separate female and male flowersMays Only one species in genus - corn

20.Using the accompanying table, all of the following characteristics are used to establish the family level of classification for corn except:

*A. grasses with hollow stems.*B. fruit is a grain.*C. large endosperm in the seed.*D. one seed leaf.*E. None of the above, all are used to define the family level of

classification for corn.

21.Based on the information in the table, one characteristic used at the class level of classification for corn is:

*A. flower parts in fours or fives.*B. separate male and female flowers.*C. the presence of a single seed leaf.

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*D. flowering vascular plants.*E. tall annual grasses.

22, 23. Use the figure to answer the corresponding questions.

22.The animals in the associated figure are all representative of the:

*A. Class Carnivora.*B. Order Carnivora.*C. Phylum Animalia.*D. Class Chordata.*E. Order Mammalia.

23.The taxonomic grouping that would represent the next highest (more inclusive) level above that represented in the figure is:

*A. Family.*B. Order.*C. Class.*D. Phylum.*E. None of the above.

24. If a gene were transferred naturally by a bacterium from a plant genome to a insect genome it would be an example of:

*A. transposon activity.*B. genome shuffling.*C. lateral gene transfer.*D. genome switching.*E. restriction.

25.The original two Kingdoms that were established to organize living organisms were:

*A. Protista and Animalia.*B. Eukaryotae and Prokaryotae.

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*C. Plantae and Animalia.*D. Plantae and Eukarya.*E. Eubacteria and Eukarya.

26.Early biologists classified living things into two kingdoms. Many biologists today recognize ____________ kingdom(s).

*A. one*B. two*C. three*D. six*E. twelve

27.Bacteria are found in the Kingdom:

*A. Eubacteria.*B. Fungi.*C. Protista.*D. Animalia.*E. Plantae.

28.Which Kingdom contains the protozoa, water and slime molds, and algae?

*A. Prokaryotae*B. Fungi*C. Protista*D. Animalia*E. Plantae

29.Which of the following does not describe members of the Kingdom Fungi?

*A. absorb nutrients produced by other organisms*B. possess cell walls*C. not photosynthetic*D. cells lack a nucleus*E. yeasts and mushrooms

30.Fungi may be differentiated from plants, because fungi are:

*A. photosynthetic.*B. all macroscopic.*C. all multicellular.*D. heterotrophic.*E. all prokaryotic.

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31.Molecular evidence indicating less than 50% shared genes was the basis for:

*A. dividing the prokaryotes into two kingdoms, the Eubacteria and the Archaebacteria.

*B. separating the kingdom Protista from the kingdom Animalia.*C. including algae and slime molds in the kingdom Protista.*D. the separation of eukaryotes and prokaryotes.*E. placing fungi in a separate kingdom.

32.The evolutionary history of a group of organisms from a common ancestor is termed:

*A. biohistory.*B. phylogeny.*C. phrenology.*D. phenetics.*E. species origenetics.

33.An example of homologous structures is the wing of a bat and:

*A. the arm of a human.*B. the wing of a beetle.*C. the tail of a whale.*D. the leg of a chimpanzee.*E. the dorsal fin of a shark.

34.An example of homoplastic structures is the wing of a butterfly and:

*A. the wing of a moth.*B. the wing of a bird.*C. the antenna of the butterfly.*D. the legs of the butterfly.*E. the antenna of a moth.

35.Humans, as well as other mammals ranging from mice to elephants, have hair. Hair, then, would be considered to be:

*A. a derived character.*B. an ancestral character.*C. a cladistic character.*D. an analogous character.*E. a polyphyletic character.

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36.Sea snakes, which are reptiles, are similar in body form to eels, which are fish. Sea snakes and eels therefore share ________________ body form.

*A. ancestral*B. homoplastic*C. homologous*D. monophyletic*E. cladistic

37.Homoplastic structures are a result of ________________ evolution.

*A. convergent*B. divergent*C. the absence of*D. multiphyletic*E. derived

38.Because whales breathe via lungs, have a little hair when born, and nurse their young, these _______________ characters allow us to classify them as mammals.

*A. pleisomorphic*B. homoplastic*C. cladistic*D. polyphyletic*E. derived

39.A(an) __________________ character is a trait that has evolved relatively recently.

*A. derived*B. ancestral*C. cladistic*D. homologous*E. polyphyletic

40.Shared ancestral characters may also be called:

*A. heteroplastic characters.*B. synapomorphic characters.*C. pleisomorphic characters.*D. outgroups.*E. phenetic characters.

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41.When considering whales and dolphins, the relative absence of hair is considered a ______________ within mammals.

*A. pleisomorphic character*B. ancestral character*C. synapomorphic character*D. phenetic character*E. cladistic character

42.Scientists may compare similarities between nucleotide sequences of organisms to determine their evolutionary history. This is known as:

*A. synapomorphy.*B. molecular systematics.*C. monophyletic grouping.*D. cladistics.*E. phenetics.

43.Comparison of the nucleotide sequences of a region of the genomes from the human, gorilla, and chimpanzee revealed that:

*A. humans are most closely related to the chimpanzee.*B. the common ancestor of the gorilla, chimpanzee, and human

diverged into 3 lines.*C. the chimpanzee is more closely related to the gorilla than the human.*D. the gorilla and chimpanzee have virtually identical sequences.*E. None of the above.

44.Comparison of ______________________ has been recently used to support the hypothesis that fungi are more closely related to animals than to plants.

*A. mitochondrial DNA sequences*B. mitochondrial tRNA sequences*C. ribosomal RNA sequences*D. ribosomal protein sequences*E. histone sequences

45.A study of the mitochondrial DNA of dog breeds around the world indicated that:

*A. all dogs appeared to develop from a mixture of wolf and coyote.*B. all dogs appeared to evolve from a mixture of the jackal and the wolf.

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*C. all dogs appeared to evolve from a mixture of the wolf, jackal, and the coyote.

*D. some dogs evolved from the coyote and some from the wolf.*E. all dogs appeared to evolve from a single origin from wolves.

46.Shared homologous structures would indicate that two taxa are:

*A. polyphyletic.*B. monophyletic. *C. outgroups.*D. in different clades.*E. homoplastic.

47.A taxon that includes all the descendants of an ancestor is called:

*A. paraphyletic.*B. homophyletic.*C. monophyletic.*D. phenetic.*E. polyphyletic.

48.All of the taxa in a monophyletic group can be called a:

*A. division.*B. class.*C. clade.*D. phyla.*E. derivative.

49.The current class Reptilia is:

*A. monophyletic.*B. paraphyletic.*C. polyphyletic.*D. heterophyletic.*E. phenetic.

50. If a biologist classifies organisms based on enumeration of similarities between taxa, the ____________ system is being used.

*A. cladistic*B. phenetic*C. phyletic*D. classical

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*E. monophyletic

51.The phenetic system is based primarily on:

*A. known evolutionary relationships.*B. fossil evidence.*C. the number of shared characteristics.*D. the number of ancestral characteristics.*E. both ancestral and shared characteristics.

52.A cladist would attempt to classify organisms into ____________ taxa.

*A. paraphyletic*B. polyphyletic*C. derived*D. phenotypic*E. monophyletic

53.Phylogenetic systematics produces branching diagrams called:

*A. phylogenic trees.*B. cladistic trees.*C. phenograms.*D. molecular clocks.*E. cladograms.

54.A cladogram is based on:

*A. homologous characteristics.*B. homoplastic characteristics.*C. polyphyletic taxa.*D. fossil evidence only.*E. derived characters only.

55.A taxon that diverges earlier than the other taxa being considered in cladistic analysis is:

*A. a homologous taxon.*B. an outgroup.*C. a derived taxon.*D. an Amphioxus.*E. a clade.

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56.When faced with multiple possible cladograms, the criteria of ________ is employed.

*A. biodiversity*B. subtraction*C. evolutionary deduction*D. parsimony*E. cladology

57.Classical evolutionary taxonomy includes:

*A. some characteristics of both cladistics and phenetics.*B. only monophyletic groups.*C. only polyphyletic groups.*D. only derived characters.*E. only ancestral characters.

58.The scientist credited with developing the modern system of classification used today is:

*A. St. Augustine.*B. Aristotle.*C. Cavalier-Smith.*D. Woese.*E. Linnaeus.

59-61. Use the figure to answer the corresponding questions.

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59.The organism labeled B in the accompanying figure is a common ancestor to:

*A. organism 2.*B. organism 3.*C. organism 5.*D. organism 6.*E. All of the above.

60. In the accompanying figure, the pair of organisms that have the most recent ancestor is:

*A. 2 and 4.*B. 6 and 4.*C. 4 and 5.*D. 2 and 3.*E. 1 and 2.

61. In the accompanying figure, the taxon labeled II is:

*A. monophyletic.*B. paraphyletic.*C. polyphyletic.*D. a clade.*E. an outgroup.

SHORT ANSWER QUESTIONS

Arrange the Linnaean categories in hierarchical fashion, from most inclusive to least inclusive, starting at the level of domain. BONUS: Insert the appropriate names for each category for a particular organism, such as corn or humans. Partial credit will be given.

Identify and briefly discuss two difficulties encountered in choosing taxonomic criteria. Use specific examples in your discussion.

Contrast the following terms: monophyletic, paraphyletic, and polyphyletic. Provide one example for each.

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DISCUSSION OR THOUGHT QUESTIONS

1. Construct a table with the six kingdoms listed. Identify several members of each kingdom, as well as diagnostic features of each kingdom.

Concepts to Consider: kingdom Plantae — eukaryotic, mostly photosynthetic, complex reproductive structures, cell walls of cellulose, the plants; kingdom Animalia — eukaryotic, heterotrophic, mostly multicellular, usually with nervous tissues, motile, the animals; kingdom Fungi — eukaryotic, heterotrophic, mostly multicellular, bodies formed by hyphae, cell walls of chitin; kingdom Protists — eukaryotic, photosynthetic or heterotrophic, many are unicellular, many are motile; kingdom Eubacteria — prokaryotic, varied metabolism, may be pathogenic, cell wall of peptidoglycan in most, the bacteria; kingdom Archaebacteria — the bacteria adapted to live in unusual habitats, including the methanogens, halophiles, and extreme thermophiles, cell walls without peptidoglycan.

2. A new species of beetle is discovered. If you were a cladist, what steps might you take to classify this beetle? How might this approach be different if you were a pheneticist?

Concepts to Consider: Cladists study shared and ancestral characters and attempt to identify outgroups; pheneticists use a numerical approach and quantify shared characteristics to determine taxonomic classification.

3. Describe the biological basis of the species taxon. If there were not humans on earth to classify organisms, would species still exist?

Concepts to Consider: Taxonomy is based on evolutionary relationships; the species concept is based on reproductive isolation and is therefore a biological premise. Species would exist whether we are here to name them or not; other taxa are also based on evolutionary ties, at least by cladists and systematists using the classic evolutionary approach.

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Viruses and Prokaryotes


LEARNING OBJECTIVES


1. Describe the structure of a virus and compare a virus with a free-living cell.

2. Trace the evolutionary origin of viruses according to current hypotheses.

3. Characterize bacteriophages and contrast a lytic cycle with a lysogenic cycle.

4. Explain how viruses infect animal and plant cells.

5. Describe the reproductive cycle of a retrovirus such as human immunodeficiency virus.

6. Compare and contrast viroids and prions.

7. Describe the structure and common shapes of prokaryotic cells.

8. Describe asexual reproduction in prokaryotes and summarize three mechanisms (transformation, conjugation, and transduction) that may lead to genetic recombination.

9. Characterize the metabolic diversity of autotrophic and heterotrophic prokaryotes, including aerobes, facultative anaerobes, and obligate anaerobes.

10. Compare the three domains: Eubacteria, Archaea, and Eukarya.

11. Distinguish among the three main groups of archaea and among several groups of eubacteria as described in Table 23–3. Give examples of each group.

12. Discuss the ecological roles of prokaryotes, their importance as pathogens, and their commercial importance.


1. Many microscopic organisms or entities have been identified as pathogens, including all of the following except:

*A. protozoa.*B. viruses.*C. fungi.*D. bacteria.*E. None of the above, all may be pathogenic.

2. Which of the following statements about bacteria is false?

*A. A small percentage of bacteria are pathogenic.

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*B. Some bacteria can photosynthesize.*C. Bacteria are important decomposers.*D. Bacteria are not cellular and are sometimes not classified as life forms.*E. Bacteria convert atmospheric nitrogen into ammonia and then nitrates that

can be used by plants.

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3. Viruses were first identified:

*A. because they caused an infection and formed colonies on nutrient agar plates.

*B. because they were seen in the light microscope.*C. because they caused an infection and were small enough to pass through

filters that trapped bacteria.*D. because they were smaller than bacteria and had all the properties of living

organisms.*E. because they caused an infection and were seen in the electron

microscope.

4. The protein coat of a virus is called the:

*A. capsule.*B. capsid.*C. exospore.*D. phage.*E. pilus.

5. Viruses that attack bacteria are called:

*A. phages.*B. bacteriods*C. prions.*D. virons.*E. viroids.


6. The structure of the virus in the accompanying figure that is common to all viruses is:

*A. 2.*B. 3.*C. 4.*D. 5.*E. All of the above.

7. The function of the structure labeled 3 is:

*A. attachment to a host cell.*B. locomotion.

*C. mate recognition.*D. replication.*E. to take over host cell

mechanisms.

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8. Viruses are classified by:

*A. the sequence of their DNA.*B. structural similarities.*C. the sequence of their rRNA genes.*D. the traditional Linnaean binomial nomenclature system.*E. an international committee.

9. Viruses:

*A. are very tiny cells on the order of 500 nm.*B. contain both RNA and DNA.*C. cannot independently perform metabolic activities.*D. have a standard morphology that includes a capsid, tail, and tail fibers.*E. All of the above.

10.Viruses:

*A. are usually species-specific.*B. may have multiple origins.*C. are probably related to mobile genetic elements.*D. may have escaped from cells.*E. All of the above.

11.Phages are being considered for:

*A. vectors in gene therapy experiments.*B. antibiotics in bacterial infections.*C. gene transfer vectors in animal cells.*D. being equivalent to the first living organisms.

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*E. All of the above.

12.Temperate viruses:

*A. always destroy their host immediately.*B. are considered virulent.*C. do not always destroy their host.*D. do not undergo a lysogenic cycle.*E. undergo a lytic cycle.

13.Virulent (lytic) phages:

*A. infect viruses.*B. destroy bacteria.*C. infect, but do not destroy bacteria.*D. infect virions.*E. infect prions.

14.The five stages of a lytic infection are attachment, penetration, _____________, assembly, and release.

*A. lysis*B. prophage*C. lysogenesis*D. transduction*E. replication

15.A prophage:

*A. is phage DNA that is integrated into viral DNA.*B. is phage DNA that is integrated into bacterial DNA.*C. replicates only when the eukaryotic cell it infects replicates.*D. is an underdeveloped lytic virus.*E. is a bacterial cell about to lyse.

16.The bacterium that causes botulism disease is harmless until it:

*A. is infected by lytic bacteria.*B. is infected by certain retroviruses.*C. contains a certain prophage DNA.*D. is irradiated by UV radiation.*E. is infected by prions.

17.____________ conversion occurs when a bacterium carrying viral genes takes on new, atypical characteristics.

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*A. Transducing*B. Lysogenic*C. Prophage*D. Lytic*E. Reverse

18.The specificity of viruses to different types of cells is due to _____________ sites on the host cell.

*A. prophage*B. receptor*C. transduction*D. penetration*E. transcription

19.Retroviruses differ from other RNA viruses by:

*A. having reverse transcriptase instead of RNA-dependent RNA polymerase.*B. the shape of their capsid.*C. the way they infect their host cells.*D. the sugar coating on their capsids.*E. lytically destroying their hosts.

20.Which of the following diseases is not caused by a virus?

*A. rabies*B. polio*C. warts in humans*D. chickenpox*E. Lyme disease

21.Which of the following identifies a group of DNA viruses?

*A. retroviruses*B. herpesviruses*C. paramyxoviruses*D. filovirus*E. picornaviruses

22.Viral proteins can damage host cells by:

*A. increasing the rate of fermentation within the host.*B. producing endotoxins.*C. causing a decline in coordination and increased irritability.

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*D. preventing transcription of viral nucleic acids.*E. overwhelming the host cell with a large number of viruses.

23.Viral infections in humans spread via the circulatory system. Viral infections in plants spread from cell to cell via:

*A. endocytosis.*B. plasmodesmata.*C. infected seeds.*D. pili.*E. transformation.

24.Human viruses can enter human cells by fusion with the cell membrane or by:

*A. diffusion into the cell.*B. passage through specific protein channels.*C. coating themselves with lipids that cloak their entrance into the cell.*D. endocytosis.*E. hitchhiking onto protein signals entering the cell.

25.Viroids cause a variety of plant diseases and are composed only of:

*A. strands of RNA.*B. strands of DNA.*C. protein coats.*D. peptidoglycan.*E. a capsid.

26.Mad cow disease is an example of an infection caused by a:

*A. bacterium.*B. bacteriophage.*C. retrovirus.*D. viroid.*E. prion.

27._____________ is credited with the discovery of prions as a new biological principle of infection.

*A. Stanley Prusiner*B. Anton van Leeuwenhoek*C. Dmitrii Ivanowsky*D. Stanley Brenner*E. Carl Woese

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28.A symptom of a transmissible spongiform encephalopathy (TSE) is:

*A. degeneration of the digestive tract.*B. progressive immune deficiency.*C. degeneration of the brain and central nervous system.*D. inflammation of the reproductive organs.*E. influenza-like symptoms.

29.The volume of a typical bacterium is about ____________ the volume of a typical eukaryotic cell.

*A. equal to*B. a half*C. a tenth*D. a hundredth*E. a thousandth

30.A chain of round bacteria would be called:

*A. spirilla.*B. diplococci.*C. bacilli.*D. streptococci.*E. streptobacilli.

31.Rod-shaped bacteria are called:

*A. streptococci.*B. bacilli.*C. diplococci.*D. vibrio.*E. spirochete.


32.The structure in the accompanying figure labeled C is:

*A. a ribosome.*B. the plasma membrane.*C. the capsule.*D. the cell wall.*E. the flagellum.

33.What is the function of the structure labeled A in the accompanying figure?

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*A. to adhere to surfaces or other bacteria*B. to prevent phagocytosis*C. support and protection in hypotonic conditions*D. transmission of DNA between bacteria*E. locomotion

34.Even though bacteria lack membrane-bound organelles, such as chloroplasts and mitochondria, they can still perform the functions of these organelles by localizing certain metabolic enzymes on:

*A. the nuclear membranes.*B. the endoplasmic reticulum.*C. the plasma membrane.*D. ribosomes.*E. the cell wall.

35.Most bacterial cells keep from bursting in a hypotonic environment by:

*A. an efficient water pump.*B. a tough cell membrane.*C. pumping large quantities of salts into the cell.*D. a rigid cell wall.*E. a stiff capsule.

36.Gram-positive bacteria would stain __________ in a gram stain because of a thick layer of __________ in their cell walls.

*A. green; peptidoglycan*B. purple; peptidoglycan*C. green; cellulose*D. purple; polysaccharides*E. red; polysaccharides

37.The walls of Eubacteria contain peptidoglycan, which is:

*A. lipids crosslinked with sugars.*B. sugars crosslinked with proteins.*C. a protein.*D. a lipid.*E. a polysaccharide.

38.Penicillin works most effectively against gram-positive bacteria because:

*A. penicillin affects cell membranes.

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*B. they have a thick peptidoglycan cell wall and penicillin affects the synthesis of peptidoglycans.

*C. they have special protein channels that allow penicillin to enter the cell and halt the cell cycle.

*D. they are smaller than gram-negative bacteria and, thus, easily take up penicillin by diffusion.

*E. they contain prophages that negatively interact with penicillin.

39.Some bacteria avoid a host’s immune system by means of:

*A. efficient use of their flagella.*B. ameboid motion.*C. their capsule.*D. changing their cell wall structure.*E. eliminating the use of a membrane.

40.Bacteria:

*A. are incapable of locomotion.*B. move by means of pili *C. move by means of cilia.*D. move by means of a rotating flagella.*E. move by means of a whiplike flagella.

41.Small circles of DNA called ______________ exist in addition to the bacterial chromosome.

*A. capsids*B. plasmids*C. chromatids*D. pili*E. centromeres

42.Small hairlike structures on the surface of bacteria are called:

*A. capsids.*B. pili.*C. chromatids.*D. plasmids.*E. virons.

43.Plasmids of bacteria often have genes involved in:

*A. reproduction.*B. motility.

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*C. viral resistance.*D. antibiotic resistance.*E. photosynthesis.

44.Pili are involved in adhesion of bacterial cells to a substrate or host, or in transmission of __________ between bacteria.

*A. ribosomes*B. cytoplasm*C. vectors*D. RNA*E. DNA

45.Prokaryotes have their genetic information stored in:

*A. several small, circular pieces of DNA.*B. a single, small, circular piece of DNA.*C. a large, linear piece of DNA.*D. several small, linear pieces of DNA.*E. a large, circular piece of DNA.

46._______________ is a form of genetic exchange in bacteria that involves contact between two cells.

*A. Transformation*B. Transduction*C. Conjugation*D. Binary fission*E. Budding

47._____________ are dormant structures formed by bacteria in response to adverse environmental conditions.

*A. Capsids*B. Endospores*C. Exotoxins*D. Endotoxins*E. Heterocysts

48.Most bacteria are:

*A. photoheterotrophs.*B. chemoheterotrophs.*C. autotrophs.*D. heterotrophs.

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*E. chemoautotrophs.

49.A bacterium that gains nourishment from dead organisms is referred to as:

*A. an autotroph.*B. a parasite.*C. a saprotroph.*D. a chemoautotroph.*E. a pathogen.

50.A(an) ___________________ bacterium would not be able to survive in the presence of oxygen.

*A. facultative aerobic*B. facultative anaerobic*C. facultative autotrophic*D. obligate aerobic*E. obligate anaerobic

51.The most common mode of reproduction in bacteria is:

*A. binary fission.*B. transformation.*C. transduction.*D. conjugation.*E. mitosis.

52.The first indication that Archae were different from the Eubacteria came from differences noted in their:

*A. cell wall.*B. preferred habitats.*C. 16 S rRNA sequence.*D. protein synthesis machinery.*E. resistance to antibiotics.

53.The Archaea differ from the Eubacteria and eukaryotes by having different ____________ in their cell membranes, but they are similar to eukaryotes in their ____________ process.

*A. sugars; replication*B. sugars; transcription*C. lipids; replication*D. lipids; transcription*E. proteins; transcription

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54.Which of the following groups from the accompanying figure represents gram-negative bacteria?

*A. Spirochetes*B. Protists*C. Methanogens*D. Halophiles*E. None of the above.

55.Which of the following groups from the accompanying figure is a member of the Eubacteria domain?

*A. Fungi*B. Halophiles*C. Chlamydias*D. Protists*E. More than one of the above.

56.About how many different species of bacteria have been classified?

*A. 200*B. 2,000*C. 4,000*D. 20,000*E. 40,000

57.The most significant difference between the Archaea and the Eubacteria is:

*A. lack of a nuclear envelope in the Archaea.*B. the absence of the 70S ribosomes in the Eubacteria.*C. the presence of a single filament flagellum in the Eubacteria.*D. the absence of peptidoglycans in the cell walls of the Archaea.*E. All of the above.

58.One difference between the Archaea and the Eukarya is:

*A. the lack of a nuclear envelope in the Archaea.*B. the absence of the 70S ribosomes in the Archaea.*C. the presence of membrane-bound organelles in the Archaea.*D. the presence of peptidoglycans in the cell walls of the Archaea.

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*E. the presence of simple RNA polymerase in the Archaea.

59.One unique characteristic associated with some of the extreme halophilic Archaea is:

*A. that they are found at deep-sea vents on the sea floor.*B. that they are a source of most known antibiotics.*C. that they have photosynthetic ability involving a purple bacteriorhodopsin

pigment.*D. that they fix atmospheric nitrogen that is then used by plants.*E. that most form symbiotic associations.

60._____________ Archae are typically found in abnormally hot environments.

*A. Extreme halophile*B. Extreme thermophile*C. Pyrrhanogen*D. Metanogen*E. Any of the above.

61.Most prokaryotes belong to the:

*A. Fungi.*B. Archaea.*C. Protista.*D. Eubacteria.*E. Viroids.

62.Bacterial ____________ cause systemic symptoms such as fever, whereas bacterial ____________ cause more specific maladies.

*A. phages; prophages*B. prophages; phages*C. endotoxins; exotoxins*D. exotoxins; endotoxins*E. exotoxins; phages

63.The bacterial reproductive parasite Wolbachia is known to:

*A. eradicate males from a population.*B. convert males into females.*C. cause infected females to lay eggs that develop without fertilization.*D. reduce the number of males in a population.*E. All the above.

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64.The symbiotic bacteria found in the root nodules of legumes:

*A. supply the plant with the nitrogen it needs in the form of nitrates.*B. are motile, soil-dwelling bacteria.*C. belong to the genus Rhizobium.*D. are gram-negative Eubacteria.*E. All of the above.

65.Koch’s postulates include all the following except:

*A. when a sample of a pure culture is injected into a healthy host causes the same disease.

*B. a sample of the microorganism from a diseased host can be grown in pure culture.

*C. the microorganism can be recovered from an experimentally infected host.*D. the microorganism must be visible in the electron microscope.*E. the pathogen must be present in every individual with the disease.

66.The first bacteria that was clearly identified as the cause of an infectious disease was:

*A. Legionella pneumophila, which causes Legionnaires’ disease.*B. Chamydia sp., which causes pelvic inflammatory disease in women.*C. Clostridium botulinum, which causes botulism.*D. Vibrio cholerae, which causes cholera.*E. Bacillus anthracis, which causes anthrax.


1. Compare and contrast a virus and a bacterium.

List the characteristics of the following groups and identify examples for each: Archaea, Eubacteria, and Eukarya.

Compare and contrast the metabolic diversity of bacteria in one of the two groups below.

A. Obligate anaerobes, facultative anaerobes, and aerobesB. Autotrophic and heterotrophic bacteria

Identify and briefly discuss two ecological roles filled by bacteria.


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1. Describe the theory that attempts to explain the species specificity of viruses to their hosts.

Concepts to Consider: Viruses may have come about by escaping from cellular organisms such as bacteria, plants, and animals. It may be that viruses can only infect organisms from which they originated. This could explain why viruses are very specialized concerning their hosts.

2. Discuss the distinction between gram-negative and gram-positive bacteria. In the laboratory, how is this determined? What are differences between these two groups of bacteria?

Concepts to Consider: Gram-positive bacteria are those that absorb and retain crystal violet, a violet pigment that shows under a microscope. Gram-negative do not retain this pigment and, therefore, appear red. This effect is due to the fact that gram-positive bacteria have very thick peptidoglycan cell walls, which absorb and retain the crystal violet pigment. Gram-negative bacteria do not have thick cell walls and, therefore, do not retain the pigment very well. The differences in the cell walls between gram-positive and gram-negative bacteria have a bearing on how certain drugs affects these two bacterial types. Gram-positive bacteria are very susceptible to penicillin because their cell walls are weakened by the drug. Gram-negative bacteria are not easily harmed by penicillin. As a result, gram-negative bacteria are much harder to control.

3. Describe endotoxins and exotoxins. What effects do they each have on infected persons?

Concepts to Consider: Endotoxins are toxins that are released from bacteria after they have died or lysed. These toxins are a component of the bacterial cell wall or the internal environment and cause systemic symptoms such as fever and edema. Exotoxins are those released into the environment (host) by living bacteria. They result in a very broad range of toxin-specific symptoms.

31

The Protists

The Protists

LEARNING OBJECTIVES


1. Characterize the features common to the members of kingdom Protista.

2. Discuss in general terms the diversity inherent in the protist kingdom, including means of locomotion, modes of nutrition, interactions with other organisms, habitats, and modes of reproduction.

3. Discuss the endosymbiont theory, and briefly explain some of the evidence that supports it.

4. Describe the kinds of data biologists use to classify eukaryotes.

5. Explain why zooflagellates are no longer classified in a single phylum, and distinguish among diplomonads, euglenoids, and choanoflagellates.

6. Briefly describe and compare the following alveolates: ciliates, dinoflagellates, and apicomplexans.

7. Briefly describe and compare the following heterokonts: water molds, diatoms, golden algae, and brown algae.

8. Describe the foraminiferans and actinopods, and explain why many biologists classify them in the monophyletic group Cercozoa.

9. Support the hypothesis that red algae and green algae are a monophyletic group with land plants.

10. Briefly describe and compare the following Amoebozoa: amoebas, plasmodial slime molds, and cellular slime molds.


1. Most protozoa may be characterized as:

*A. autotrophic.*B. heterotrophic.*C. photosynthetic.*D. chemotrophic.*E. anisogamous.

2. Most protists are:

*A. aquatic.*B. parasitic.

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The Protists

*C. terrestrial.*D. arboreal.*E. None of the above.

3. Based on the most recent data available, the protist kingdom is:

*A. paraphyletic.*B. monophyletic.*C. composed only of unicells.*D. composed of both eukaryotes and prokaryotes.*E. entirely microscopic.

4. The informal group designated as the protozoa include all of the following except:

*A. ameoeba.*B. ciliates.*C. diatoms.*D. foraminifera.*E. zooflagellates.

5. Members of phylum ____________ move via pseudopodia.

*A. Rhizopoda*B. Zoomastigina*C. Ciliophora*D. Oomycota*E. Chrysophyta

6. Members of which phylum have formed deposits of chalk, as seen in the white cliffs of Dover?

*A. Rhizopoda*B. Zoomastigina*C. Ciliophora*D. Foraminifera*E. Actinopoda

7. Pseudopodia are used by Amoeba for ingesting food as well as for:

*A. reproduction.*B. excretion.*C. digestion.*D. movement.*E. avoiding predation.

8. Among the protist phyla below, which has organisms that typically move with one

33

The Protists

or more flagella?

*A. Rhizopoda*B. Retortmonada*C. Ciliophora*D. Foraminifera*E. Actinopoda

9. Which phylum contains the organism Trypanosoma, which causes African sleeping sickness?

*A. Rhizopoda*B. Euglenozoa*C. Ciliophora*D. Foraminifera*E. Actinopoda

10.Members of phylum Alveolata possess ____________, which are ejectile filaments used in trapping prey.

*A. contractile vacuoles*B. micronuclei*C. macronuclei*D. heterocysts*E. trichocysts


11.The function of the structure labeled 4 is:

*A. food intake.*B. digestion.*C. waste elimination.*D. water discharge.*E. asexual reproduction.

12.The function of the structure labeled 6 is:

*A. food intake.*B. digestion.*C. waste elimination.*D. water discharge.*E. asexual reproduction.

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The Protists

13.Malaria is caused by an ___________________, which is carried to a host by a ______________.

*A. apicomplexan; fly*B. apicomplexan; mosquito*C. apicomplexan; body louse*D. actinopod; fly*E. actinopod; mosquito

14.Algae are not considered true plants, as they lack both a cuticle and:

*A. multicellular bodies.*B. multicellular gametangia.*C. thalli.*D. frustules.*E. cell walls.


15.The process occurring in the cells labeled 2 in the sequence is:

*A. fertilization.*B. syngamy.*C. the first meiotic division.*D. the second meiotic division.*E. mitosis.

16.The process occurring in the cells labeled 6 is:

*A. fertilization.*B. syngamy.*C. the first meiotic division.*D. the second meiotic division.*E. mitosis.

17.The outcome of the process illustrated in the accompanying figure is:

35

The Protists

*A. four new genetically identical cells that differ genetically from what they were before.

*B. four new but genetically distinct cells.*C. two new genetically identical cells that differ genetically from what they were

before.*D. two new but genetically distinct cells.*E. one male and one female cell.

18.Classification of algae into the various protist phyla is based on their photosynthetic pigments and:

*A. cellular storage compounds.*B. presence of cell walls.*C. where they live.*D. the diseases they cause.*E. the presence of DNA or RNA.

19.Which phylum includes algae that are typically unicellular and form siliceous shells?

*A. Chlorophyta*B. Rhodophyta*C. Euglenophyta*D. Dinoflagellata*E. Bacillariophyta

20.The commercially important unicellular protists that are used in filters, polishes, and other industrial processes are the:

*A. dinoflagellates.*B. euglenoids.*C. apicomplexans.*D. zooflagellates.*E. diatoms.

21.Members of this phylum have both plant-like and animal-like characteristics, making classification difficult.

*A. Chlorophyta*B. Rhodophyta*C. Euglenophyta*D. Oomycota*E. Bacillariophyta

36

The Protists

22.These algae are often used as indicators of organic pollution such as sewage in a lake or stream.


23.These algae often have intracellular shells of interlocking plates.


24.Members of which phylum are one of the most important producers in marine ecosystems, although sometimes they form blooms known as red tides?

*A. Chlorophyta*B. Rhodophyta*C. Euglenophyta*D. Dinoflagellata*E. Phaeophyta

25.Toxins produced by red tides are known to have impacted all of the following except:

*A. birds.*B. fishes.*C. humans.*D. manatees.*E. None of the above, all are impacted by red tides.

26.Brown algae lack true roots but have similar structures called ____________ that anchor them to the substrate.

*A. stipes*B. fronds*C. holdfasts*D. blades*E. thalli

37

The Protists

27.All of the following statements about the phylum Phaeophyta are true except:

*A. this group includes the most complex algae that have blades, stipes, and holdfasts.

*B. they share a common ancestor with representatives of the plant kingdom.*C. they represent the largest members of the kingdom Protista.*D. they are harvested for algin, which is used in a variety of commercial

products.*E. they are ecologically important as producers and in providing habitats along

rocky coastlines.

28.Of the following algae, which phylum exhibits the most diverse morphology, forming unicells, filaments, and sheets?

*A. Chlorophyta*B. Phaeophyta*C. Euglenophyta*D. Dinoflagellata*E. Bacillariophyta

29.Members of the phylum ___________________ are thought to have given rise to plants.


30.Green algae exhibit alternation of generations and varied sexual reproduction. When their sexual reproduction involves the fusion of flagellated gametes of different sizes, it is known as:

*A. oogamy.*B. anisogamy.*C. isogamy.*D. heterogamy.*E. fission.


31.The Chlamydomonas at point 4 in the life cycle:

*A. are haploid gametes.*B. were produced by mitosis.

*C. are negative (–) strain.*D. are part of the haploid generation.*E. All of the above.

32.The structure at point 6 in the life cycle:

38

The Protists

*A. is a zoospore.*B. was produced by mitosis.*C. was produced by meiosis.*D. is diploid.*E. None of the above.

33.The process occurring at point 1 in the life cycle is:

*A. fertilization.*B. sexual reproduction.*C. meiosis.*D. asexual reproduction.*E. syngamy.

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34.Some green algae, such as Codium, attain very large sizes, but are a single cell with multiple nuclei. This condition is known as:

*A. mycelium.*B. alternation of generations.*C. multicellular.*D. coenocytic.*E. colonial.

35.Which of the following protist phyla does not have flagellated cells?

*A. Oomycota*B. Phaeophyta*C. Euglenophyta*D. Rhodophyta*E. Chrysophyta

36.Members of this phylum are typically multicellular and have phycoerythrin and phycocyanin as their accessory photosynthetic pigments.

*A. Rhodophyta*B. Phaeophyta*C. Dinoflagellata*D. Euglenophyta*E. Chlorophyta

37.Which group of algae are a commercial source of agar and carrageenan?


38.Coralline forms of members of this phylum are ecologically important in the formation of coral reefs.


39.Fungus-like protists aren't fungi, because the protists have ____________ in

their cell walls and possess ____________, wheras fungi do not.

*A. cellulose; flagella*B. chitin; centrioles*C. chitin; flagella*D. cellulose; centrioles*E. chitin; cilia

40.Members of this phylum are characterized by a multinucleate amoeboid-like feeding form called a plasmodium.

*A. Myxomycota*B. Oomycota*C. Rhodomycota*D. Phaeophyta*E. Acrasiomycota

41.A water mold, from phylum ________________, was responsible for the late blight of potatoes that caused the Irish potato famine.

*A. Myxomycota*B. Oomycota*C. Rhodomycota*D. Phaeophyta*E. Acrasiomycota

42.The ____________ are zooflagellates that are very primitive and may give biologists clues as to the evolutionary relationships between the prokaryotes and the protists.

*A. cryptomonads*B. chrysophytes*C. diplomonads*D. water molds*E. slime molds

43.Protists may move by pushing out their cytoplasmic extensions, known as:

*A. plasmadesmata.*B. pseudopods.*C. flagella.*D. cilia.*E. etrichomes.

44.Symbiotic association in which one partner benefits and the other is unaffected is

called:

*A. symbiosis.*B. mutualism.*C. commensalism.*D. parasitism.*E. None of the above.

45.Symbiotic association in which one partner lives on or in another is called:

*A. symbiosis.*B. mutualism.*C. commensalisms.*D. parasitism.*E. None of the above.

46.The base of the food web in aquatic ecosystem is:

*A. Algae.*B. Euglena.*C. Plankton.*D. plants.*E. fish.

47.First eukaryotic cells to evolve from ancestral prokaryotes were:

*A. Fungi.*B. Protists.*C. Endosymbionts.*D. Plants.*E. None of the above.

48.Mitochondria and chloroplasts in eukaryotic cells probably originated from:

*A. Fungi.*B. Protists.*C. Endosymbionts.*D. Plants.*E. None of the above.

49.Ancestors of ____________________ represent an intermediate stage in eukaryotic evolution when cells each had two haploid nuclei but fusion had not

occurred.

*A. plasmodium*B. Amoeba*C. Euglena*D. Giardia*E. Paramecium

50.Backpackers’ diarrhea, a common infection among campers and hikers, particularly in the mountains of the western United States, is caused by _________________.

*A. plasmodium*B. Amoeba*C. Euglena*D. Trypanosomas*E. Giardia

51.Euglenoids reproduce:

*A. asexually.*B. sexually.*C. both asexually and sexually.*D. do not reproduce.*E. by mating.

52.Researchers use ______________________ protists as indicator species of organic pollution.

*A. plasmodium*B. Amoeba*C. Euglenoids*D. Giardia*E. Paramecium

53.Trypanosomes reproduce:

*A. asexually.*B. sexually.*C. both asexually and sexually.*D. do not reproduce.*E. by mating.

54. In paramecium, the surface of the cell is covered with thousands of short, hairlike ___________.

*A. plasmadesmata*B. pseudopods*C. flagella*D. cilia*E. trichomes

55. In freshwater ciliates, special organelles called ______________________________ control water regulation.

*A. flagella*B. contractile vacuole*C. Food vacuole*D. Lysosome*E. peroxisome

56. In ciliates macronuclei controls ____________________________.

*A. reproduction*B. growth*C. metabolism*D. movement*E. Both B and C.

57.The symbiotic dinoflagellates, which live in the bodies of marine invertebrates such as mollusks, jellyfish, and corals, are called __________________________.

*A. Zooxanthellae*B. apicomplexans*C. sporozites*D. ciliates*E. None of the above.

58.Dinoflagellates that contribute substantially to the productivity of coral reefs are ____________.

*A. Zooxanthellae*B. apicomplexans*C. sporozites*D. ciliates*E. None of the above.

59.Water molds are members of the kingdom___________________.

*A. Protists*B. Fungi*C. Plantae*D. Eubacteria*E. Animalia

60.Sudden death of oak is caused by a (an):

*A. Protist.*B. Fungi.*C. archaebacteria.*D. Eubacteria.*E. animal parasite.


1. Identify the modes of nutrition found in members of the kingdom Protista and include two examples of each.

Compare and contrast the following representatives of the kingdom Protista.A. green algae and euglenoidsB. apicomplexans and dinoflagellatesC. cellular slime molds and amoeba

Discuss the structures that allow motility in the following phyla: Rhizopoda, Alveolata, and Ciliophora.

Discuss the commercial significance of protests.

Watermolds continue to cause problems in commercial crop production. Discuss.


1. List several diseases caused by protozoa. Include the causal organism, the phylum in which it is classified, and when possible, its means of transmission.

Concepts to Consider: Rhizopoda — Entamoeba histolytica, amoebic dysentery, transmitted via contaminated water; Acanthamoeba causes infections in contact lens users. Zoomastigina — Trypanosoma causes African sleeping sickness, transmitted via tsetse flies; Giardia intestinalis causes backpackers'

diarrhea, transmitted via contaminated water. Apicomplexa — Plasmodium causes malaria; transmitted via a mosquito. Dinoflagellata — various species cause paralytic shellfish poisoning and other neurological disorders.

2. Discuss the ecological significance of dinoflagellates.

Concepts to Consider: symbiotic dinoflagellates; population explosions (blooms) of dinoflagellates, known as red tides, may cause fish kills and paralytic shellfish poisoning in humans. A newly discovered dinoflagellate, Pfiesteria, has been shown to cause massive fish kills; exposure to this dinoflagellate has had serious consequences to humans as well.

3. Discuss the uncertainties and available evidence related to the evolutionary relationships among the photosynthetic protists and also in how they relate to the plants.

Concepts to Consider: consult Figure 24.1; also need to examine pigment composition, storage molecules, cell wall composition, and molecular data.

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