Deck 27: Bacteria and Archaea

Question 1

Chloramphenicol is an antibiotic that targets prokaryotic (70S)ribosomes, but not eukaryotic (80S)ribosomes. Which of these questions stems from this observation, plus an understanding of eukaryotic origins?

A)Can chloramphenicol also be used to control human diseases that are caused by archaeans?
B)Can chloramphenicol pass through the capsules possessed by many cyanobacteria?
C)If chloramphenicol inhibits prokaryotic ribosomes, should it not also inhibit mitochondrial ribosomes?
D)Why aren't prokaryotic ribosomes identical to eukaryotic ribosomes?
E)How is translation affected in ribosomes that are targeted by chloramphenicol?

Answer 1

C

Question 2

Prokaryotic ribosomes differ from those present in eukaryotic cytosol. Because of this, which of the following is correct?

A)Some antibiotics can block protein synthesis in bacteria without effects in the eukaryotic host.
B)Eukaryotes did not evolve from prokaryotes.
C)Translation can occur at the same time as transcription in eukaryotes but not in prokaryotes.
D)Some antibiotics can block the synthesis of peptidoglycan in the walls of bacteria.
E)Prokaryotes are able to use a much greater variety of molecules as food sources than can eukaryotes.

Answer 2

A

Question 3

Jams, jellies, preserves, honey, and other foodstuffs with high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounter such an environment

A)undergo death by plasmolysis.
B)are unable to metabolize the glucose or fructose, and thus starve to death.
C)experience lysis.
D)are obligate anaerobes.
E)are unable to swim through these thick and viscous materials.

Answer 3

A

Question 4

Which statement about bacterial cell walls is false?

A)Bacterial cell walls differ in molecular composition from plant cell walls.
B)Cell walls prevent cells from bursting in hypotonic environments.
C)Cell walls prevent cells from dying in hypertonic conditions.
D)Bacterial cell walls are similar in function to the cell walls of many protists, fungi, and plants.
E)Cell walls provide the cell with a degree of physical protection from the environment.

Question 5

Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces? 1. capsules
2. endospores
3. fimbriae
4. plasmids
5. flagella

A)1 and 2
B)1 and 3
C)2 and 3
D)3 and 4
E)3 and 5

Question 6

All the following are correct about antibiotic resistance, except

A)is an example of evolution in action
B)resistance genes are carried by F plasmids
C)resistance genes are carried by R plasmids
D)can occur as a result of mutations
E)B and C

Question 7

In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures? 1. nucleoid region
2. endospore
3. fimbriae
4. plasmids

A)1 only
B)1 and 2 only
C)1 and 4 only
D)2 and 4 only
E)1, 2, and 4

Question 8

If a bacterium regenerates from an endospore that did not possess any of the plasmids that were contained in its original parent cell, the regenerated bacterium will probably also

A)lack antibiotic-resistant genes.
B)lack a cell wall.
C)lack a chromosome.
D)lack water in its cytoplasm.
E)be unable to survive in its normal environment.

Question 9

Prokaryotes' essential genetic information is located in the

A)nucleolus.
B)nucleoid.
C)nucleosome.
D)plasmids.
E)exospore.

Question 10

The predatory bacterium, Bdellovibrio bacteriophorus, drills into a prey bacterium and, once inside, digests it. In an attack upon a gram-negative bacterium that has a slimy cell covering, what is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey's cytoplasm? 1. membrane composed mostly of lipopolysaccharide
2. membrane composed mostly of phospholipids
3. peptidoglycan
4. capsule

A)2, 4, 3, 1
B)1, 3, 4, 2
C)1, 4, 3, 2
D)4, 1, 3, 2
E)4, 3, 1, 2

Question 11

You were asked to classify a number of unknown prokaryotes. Which feature of the organisms would allow you to make a positive distinction as to whether they belong to the domain Bacteria or Archaea?

A)cell walls made of peptidoglycan
B)unicellularity
C)lack of a nucleus
D)can survive harsh environmental conditions
E)show adaptations to a broad range of habitats

Question 12

The typical prokaryotic flagellum features

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

Question 13

Which of the following is an important source of endotoxin in gram-negative species?

A)endospore
B)sex pilus
C)flagellum
D)cell wall
E)capsule

Question 14

In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located together on the same plasmid within a particular bacterium. If this bacterium readily performs conjugation involving a copy of this plasmid, then the result should be

A)a bacterium that has undergone transduction.
B)the rapid spread of tetracycline resistance to other bacteria in that habitat.
C)the subsequent loss of tetracycline resistance from this bacterium.
D)the production of endospores among the bacterium's progeny.
E)the temporary possession by this bacterium of a completely diploid genome.

Question 15

Regarding prokaryotic genetics, which statement is correct?

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

Question 16

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

A)endospore
B)sex pilus
C)cell wall
D)capsule

Question 17

Which of the following factors does not contribute to genetic diversity in prokaryotes?

A)horizontal transfer
B)rapid reproduction
C)mutation
D)meiosis

Question 18

Mycoplasmas are bacteria that lack cell walls. On the basis of this structural feature, which statement concerning mycoplasmas should be true?

A)They are gram-negative.
B)They are subject to lysis in hypotonic conditions.
C)They lack a cell membrane as well.
D)They should contain less cellulose than do bacteria that possess cell walls.
E)They possess typical prokaryotic flagella.

Question 19

Though plants, fungi, and prokaryotes all have cell walls, we place them in different taxa. Which of these observations comes closest to explaining the basis for placing these organisms in different taxa, well before relevant data from molecular systematics became available?

A)Some closely resemble animals, which lack cell walls.
B)Their cell walls are composed of very different biochemicals.
C)Some have cell walls only for support.
D)Some have cell walls only for protection from herbivores.
E)Some have cell walls only to control osmotic balance.

Question 20

Which statement about the genomes of prokaryotes is correct?

A)Prokaryotic genomes are diploid throughout most of the cell cycle.
B)Prokaryotic chromosomes are sometimes called plasmids.
C)Prokaryotic cells have multiple chromosomes "packed" with a relatively large amount of protein.
D)The prokaryotic chromosome is not contained within a nucleus but, rather, is found at the nucleolus.
E)Prokaryotic genomes are composed of circular DNA.

Question 21

Extreme halophiles

A)require methane for energy.
B)live in extremely hot environments.
C)live in extremely cold environments.
D)live in highly saline environments.
E)A and D

Question 22

We have overwhelming evidence that Bacteria and Archaea are masters of adaptation. Which key characteristic enables these prokaryotes to occupy almost every habitat on earth?

A)small size
B)fast reproductive rate
C)metabolic diversity
D)high mutation rate
E)presence of a protective cell wall

Question 23

If archaeans are more closely related to eukaryotes than to bacteria, then which of the following is a reasonable prediction?

A)Archaean DNA should have no introns.
B)Archaean chromosomes should have no protein bonded to them.
C)Archaean DNA should be single-stranded.
D)Archaean ribosomes should be larger than typical prokaryotic ribosomes.
E)Archaeans should lack cell walls.

Question 24

Mitochondria are thought to be the descendants of certain alpha proteobacteria. They are, however, no longer able to lead independent lives because most genes originally present on their chromosome have moved to the nuclear genome. Which phenomenon accounts for the movement of these genes?

A)plasmolysis
B)conjugation
C)translation
D)endocytosis
E)horizontal gene transfer

Question 25

Which of these statements about prokaryotes is correct?

A)Bacterial cells conjugate to mutually exchange genetic material.
B)Their genetic material is confined within vesicles known as plasmids.
C)They divide by binary fission, without mitosis or meiosis.
D)The persistence of bacteria throughout evolutionary time is due to their genetic homogeneity (in other words, sameness).
E)Genetic variation in bacteria is not known to occur, because of their asexual mode of reproduction.

Question 26

Which of the following is least associated with the others?

A)horizontal gene transfer
B)genetic recombination
C)conjugation
D)transformation
E)binary fission

Question 27

Which of the following obtain energy by oxidizing inorganic substances-energy that is used, in part, to fix CO₂?

A)photoautotrophs
B)photoheterotrophs
C)chemoautotrophs
D)chemoheterotrophs that perform decomposition
E)parasitic chemoheterotrophs

Question 28

Match the numbered terms to the description that follows. Choose all appropriate terms. 1. autotroph
2. heterotroph
3. phototroph
4. chemotroph
Description: a prokaryote that obtains both energy and carbon as it decomposes dead organisms

A)1 only
B)4 only
C)1 and 3
D)2 and 4
E)1, 3, and 4

Question 29

A fish that has been salt-cured subsequently develops a reddish color. You suspect that the fish has been contaminated by the extreme halophile, Halobacterium. Which of these features of cells removed from the surface of the fish, if confirmed, would support your suspicion? 1. the presence of the same photosynthetic pigments found in cyanobacteria
2. cell walls that lack peptidoglycan
3. cells that are isotonic to conditions on the surface of the fish
4. cells containing bacteriorhodopsin
5. the presence of very large numbers of ion pumps in its plasma membrane

A)2 and 5
B)3 and 4
C)1, 4, and 5
D)3, 4, and 5
E)2, 3, 4, and 5

Question 30

Match the numbered terms to the description that follows. Choose all appropriate terms. 1. autotroph
2. heterotroph
3. phototroph
4. chemotroph
Description: an organism that relies on photons to excite electrons within its membranes

A)1 only
B)3 only
C)1 and 3
D)2 and 4
E)1, 3, and 4

Question 31

In general, what is the primary ecological role of prokaryotes?

A)parasitizing eukaryotes, thus causing diseases
B)breaking down organic matter
C)metabolizing materials in extreme environments
D)adding methane to the atmosphere
E)serving as primary producers in terrestrial environments

Question 32

The thermoacidophile Sulfolobus acidocaldarius lacks peptidoglycan, but still possesses a cell wall. What is likely to be true of this species? 1. It is a bacterium.
2. It is an archaean.
3. The optimal pH of its enzymes will lie above pH 7.
4. The optimal pH of its enzymes will lie below pH 7.
5. It could inhabit certain hydrothermal springs.
6. It could inhabit alkaline hot springs.

A)1, 3, and 6
B)2, 4, and 6
C)2, 4, and 5
D)1, 3, and 5
E)1, 4, and 5

Question 33

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

Question 34

The termite gut protist, Mixotricha paradoxa, has at least two kinds of bacteria attached to its outer surface. One kind is a spirochete that propels its host through the termite gut. A second type of bacteria synthesizes ATP, some of which is used by the spirochetes. The locomotion provided by the spirochetes introduces the ATP-producing bacteria to new food sources. Which term(s)is (are)applicable to the relationship between the two kinds of bacteria? 1. mutualism
2. parasitism
3. symbiosis
4. metabolic cooperation

A)1 only
B)1 and 2
C)2 and 3
D)1, 3, and 4
E)2, 3, and 4

Question 35

In Fred Griffith's experiments, harmless R strain pneumococcus became lethal S strain pneumococcus as the result of which of the following? 1. horizontal gene transfer
2. transduction
3. conjugation
4. transformation
5. genetic recombination

A)2 only
B)4 only
C)2 and 5
D)1, 3, and 5
E)1, 4, and 5

Question 36

Match the numbered terms to the description that follows. Choose all appropriate terms. 1. autotroph
2. heterotroph
3. phototroph
4. chemotroph
Description: an organism that obtains both carbon and energy by ingesting prey

A)1 only
B)4 only
C)1 and 3
D)2 and 4
E)1, 3, and 4

Question 37

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

A)transduction.
B)transformation.
C)conjugation.
D)binary fission.
E)endosymbiosis.

Question 38

Which of the following traits do archaeans and bacteria share? 1. composition of the cell wall
2. presence of plasma membrane
3. lack of a nuclear envelope
4. identical rRNA sequences

A)1 only
B)3 only
C)1 and 3
D)2 and 3
E)2 and 4

Question 39

Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?

A)extreme halophiles
B)extreme thermophiles
C)methanogens
D)cyanobacteria
E)nitrogen-fixing bacteria that live in root nodules

Question 40

Which statement about the domain Archaea is true?

A)Genetic prospecting has recently revealed the existence of many previously unknown archaean species.
B)No archaeans can reduce CO₂ to methane.
C)The genomes of archaeans are unique, containing no genes that originated within bacteria.
D)No archaeans can inhabit solutions that are nearly 30% salt.
E)No archaeans are adapted to waters with temperatures above the boiling point.

Question 41

The figure below depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). Use this figure to answer the following questions.

During which two times can the recipient accurately be described as "recombinant: due to the sequence of events portrayed in the above figure?

A)during Times C and D
B)during Times A and C
C)during Times B and C
D)during Times A and B
E)during Times B and D

Question 42

Use the information in the following paragraph to answer the next few questions.
A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.
Adherence to the intestinal lining by this bacterium is due to its possession of

A)fimbriae.
B)pili.
C)a capsule.
D)a flagellum.
E)a cell wall with an outer lipopolysaccharide membrane.

Question 43

If the experimental population of E. coli lacks an F factor or F plasmid, and if bacteriophages are excluded from the bacterial cultures, then which of these is (are)means by which beneficial mutations might be transmitted horizontally to other E. coli cells?

A)via sex pili
B)via transduction
C)via conjugation
D)via transformation
E)Two of the responses above are correct.

Question 44

The following questions refer to the information and figure below.
In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20 000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population.

Which term best describes what has occurred among the experimental populations of cells over this eight-year period?

A)microevolution
B)speciation
C)adaptive radiation
D)sexual selection
E)stabilizing selection

Question 45

In a hypothetical situation, a bacterium lives on the surface of a leaf, where it obtains nutrition from the leaf's nonliving, waxy covering while inhibiting the growth of other microbes that are plant pathogens. If this bacterium gains access to the inside of a leaf, however, it causes a fatal disease in the plant. Once the plant dies, the bacterium and its offspring decompose the plant. What is the correct sequence of ecological roles played by the bacterium in the situation described here? Use only those that apply. 1. nutrient recycler
2. mutualist
3. commensal
4. parasite
5. primary producer

A)1, 3, 4
B)2, 3, 4
C)2, 4, 1
D)1, 2, 5
E)1, 2, 3

Question 46

If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?

A)The number of organisms on Earth would decrease by 10-20%.
B)Human populations would thrive in the absence of disease.
C)Bacteriophage numbers would dramatically increase.
D)The recycling of nutrients would be greatly reduced, at least initially.
E)There would be no more pathogens on Earth.

Question 47

If the vertical axis of the above figure refers to "Darwinian fitness," then which of the following is the most valid and accurate measure of fitness?

A)number of daughter cells produced per mother cell per generation
B)amount of ATP generated per cell per unit time
C)average swimming speed of cells through the growth medium
D)amount of glucose synthesized per unit time
E)number of generations per unit time

Question 48

The figure below depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). Use this figure to answer the following questions.

Which question, arising from the results depicted in the above figure, is most interesting from a genetic perspective, and has the greatest potential to increase our knowledge base?

A)If reciprocal crossing over could occur even if the piece of donated Hfr DNA were identical to the homologous portion of the recipient's chromosome, what prevents this from occurring?
B)What forces are generally responsible for disrupting the sex pilus?
C)How is it that a recipient cell does not necessarily become an Hfr cell as the result of conjugation with an Hfr cell?
D)What makes a cell an Hfr cell?

Question 49

The figure below depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). Use this figure to answer the following questions.

Which two processes are responsible for the shape of the curve at Time B? 1. transduction
2. entry of single-stranded Hfr DNA
3. rolling circle replication of single-stranded Hfr DNA
4. activation of DNA pumps in plasma membrane

A)1 and 2
B)1 and 4
C)2 and 3
D)2 and 4
E)3 and 4

Question 50

If new genetic variation in the experimental populations arose solely by spontaneous mutations, then the most effective process for subsequently increasing the prevalence of the beneficial mutations in the population over the course of generations is

A)transduction.
B)binary fission.
C)conjugation.
D)transformation.
E)meiosis.

Question 51

Broad-spectrum antibiotics inhibit the growth of most intestinal bacteria. Consequently, assuming that nothing is done to counter the reduction of intestinal bacteria, a hospital patient who is receiving broad-spectrum antibiotics is most likely to become

A)unable to fix carbon dioxide.
B)antibiotic resistant.
C)unable to fix nitrogen.
D)unable to synthesize peptidoglycan.
E)deficient in certain vitamins and nutrients.

Question 52

The figure below depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). Use this figure to answer the following questions.

What is occurring at Time C that is decreasing the DNA content?

A)crossing over
B)cytokinesis
C)meiosis
D)degradation of DNA that was not retained in the recipient's chromosome
E)reversal of the direction of conjugation

Question 53

The following questions refer to the information and figure below.
In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20 000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population.

Which of the following, if it occurs in the absence of any other type of adaptation listed here, is least reasonable in terms of promoting bacterial survival over evolutionary time in a? low-glucose environment?

A)increased efficiency at transporting glucose into the cell from the environment
B)increased ability to survive on simple sugars other than glucose
C)increased ability to synthesize glucose from amino acid precursors
D)increased reliance on glycolytic enzymes
E)increased sensitivity to, and ability to move toward, whatever glucose is present in its habitat

Question 54

Consider the thermoacidophile, Sulfolobus acidocaldarius. Which of the following graphs most accurately depicts the expected temperature and pH profiles of its enzymes? (Note: The horizontal axes of these graphs are double, with pH above and temperature below.)

A)
B)
C)
D)

Question 55

Members of Bacteria and Archaea benefit humans in all the following ways, with the exception of

A)convert milk to yogurt.
B)synthesize PHA that is used to make biodegradable plastic.
C)antibiotic resistance.
D)decompose organic matter in sewage.
E)produce vitamins and antibiotics.

Question 56

E. coli cells typically make most of their ATP by metabolizing glucose. Under the conditions of this experiment, what should be true of E. coli's generation time (especially early in the course of the experiment, but less so later on)?

A)Generation time should be the same as in the typical environment.
B)Generation time should be faster than in the typical environment.
C)Generation time should be slower than in the typical environment.
D)It is theoretically impossible to make any predictions about generation time under these conditions.

Question 57

Data were collected from the heterocysts of a nitrogen-fixing cyanobacterium inhabiting equatorial ponds. Study the following graph and choose the most likely explanation for the shape of the curve.

A)Enough O₂ enters heterocysts during hours of peak photosynthesis to have a somewhat-inhibitory effect on nitrogen fixation.
B)Light-dependent reaction rates must be highest between 1800 hours and 0600 hours.
C)Atmospheric N₂ levels increase at night because plants are no longer metabolizing this gas, so they are not absorbing this gas through their stomata.
D)Heterocyst walls become less permeable to N₂ influx during darkness.
E)The amount of fixed nitrogen that is dissolved in the pond water in which the cyanobacteria are growing peaks at the close of the photosynthetic day (1800 hours).

Question 58

Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be least effective at inhibiting bacterial growth?

A)Refrigeration: slows bacterial metabolism and growth.
B)Closing previously opened containers: prevents more bacteria from entering, and excludes O₂.
C)Pickling: creates a pH at which most bacterial enzymes cannot function.
D)Canning in heavy sugar syrup: creates osmotic conditions that remove water from most bacterial cells.
E)Irradiation: kills bacteria by mutating their DNA to such an extent that their DNA-repair enzymes are overwhelmed.

Question 59

Use the information in the following paragraph to answer the next few questions.
A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.
This bacterium's ability to survive in a human who is taking penicillin pills may be due to the presence of 1. penicillin-resistance genes.
2. a secretory system that removes penicillin from the cell.
3. a gram-positive cell wall.
4. a gram-negative cell wall.
5. an endospore.

A)1 or 5
B)2 or 3
C)4 or 5
D)2, 3, or 5
E)2, 4, or 5

Question 60

The figure below depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). Use this figure to answer the following questions.

How is the recipient cell different at Time D than it was at Time A?

A)It has a greater number of genes.
B)It has a greater mass of DNA.
C)It has a different sequence of base pairs.
D)It contains bacteriophage DNA.
E)Its membrane-bound DNA pumps are inactive.

Question 61

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following questions.

How many of these species probably have a cell wall that partly consists of an outer membrane of lipopolysaccharide?

A)only one species
B)two species
C)three species
D)four species
E)all five species

Question 62

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following questions.

Which species might be able to include Hfr cells?

A)species A
B)species B
C)species C
D)species D
E)species E

Question 63

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following questions.

Which species is most self-sustaining in terms of obtaining nutrition in environments containing little fixed nitrogen or carbon?

A)species A
B)species B
C)species C
D)species D
E)species E

Question 64

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following questions.

Which species should be able to respond most readily to taxes (plural of taxis)?

A)species A
B)species B
C)species C
D)species D
E)species E

Question 65

Use the following information to answer the questions below.
Nitrogenase, the enzyme that catalyzes nitrogen fixation, is inhibited whenever free O₂ reaches a critical concentration. Consequently, nitrogen fixation cannot occur in cells wherein photosynthesis produces free O₂. Consider the colonial aquatic cyanobacterium, Anabaena, whose heterocytes are described as having "…a thickened cell wall that restricts entry of O₂ produced by neighbouring cells. Intracellular connections allow heterocysts to transport fixed nitrogen to neighbouring cells in exchange for carbohydrates."
Given that the enzymes that catalyze nitrogen fixation are inhibited by oxygen, what are two "strategies" that nitrogen-fixing prokaryotes might use to protect these enzymes from oxygen? 1. couple them with photosystem II (the photosystem that splits water molecules)
2. package them in membranes that are impermeable to all gases
3. be obligate anaerobes
4. be strict aerobes
5. package these enzymes in specialized cells or compartments that inhibit oxygen entry

A)1 and 4
B)2 and 4
C)2 and 5
D)3 and 4
E)3 and 5

Question 66

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following questions.

Which species is most likely to be found both in sewage treatment plants and in the guts of cattle?

A)species A
B)species B
C)species C
D)species D
E)species E

Question 67

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following questions.

Which two species should have much more phospholipid, in the form of bilayers, in their cytoplasms than most other bacteria?

A)species A and B
B)species A and C
C)species B and E
D)species C and D
E)species C and E

Question 68

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following questions.

Gram-variable prokaryotes are, sometimes, those without any peptidoglycan. Which two species are most likely to be archaeans?

A)species A and B
B)species A and C
C)species B and E
D)species C and D
E)species C and E

Question 69

Bacteria can infect fish both externally and internally. Which is the most likely point of entry of bacteria that will cause an internal infection?

A)gills
B)skin along the dorsal side of the fish
C)skin along the ventral side of the fish
D)tail
E)fins

Question 70

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following questions.

Species D is pathogenic if it gains access to the human intestine. Which other species, if it coinhabited a human intestine along with species D, is most likely to result in a recombinant species that is both pathogenic and resistant to some antibiotics?

A)species A
B)species B
C)species C
D)species D
E)species E

Question 71

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following questions.

Which two species might be expected to cooperate metabolically, perhaps forming a biofilm wherein one species surrounds cells of the other species?

A)species A and B
B)species A and C
C)species B and E
D)species C and D
E)species C and E

Question 72

Use the following information to answer the questions below.
Nitrogenase, the enzyme that catalyzes nitrogen fixation, is inhibited whenever free O₂ reaches a critical concentration. Consequently, nitrogen fixation cannot occur in cells wherein photosynthesis produces free O₂. Consider the colonial aquatic cyanobacterium, Anabaena, whose heterocytes are described as having "…a thickened cell wall that restricts entry of O₂ produced by neighbouring cells. Intracellular connections allow heterocysts to transport fixed nitrogen to neighbouring cells in exchange for carbohydrates."
Which two questions below arise from a careful reading of this quotation, and are most important for understanding how N₂ enters heterocysts, and how O₂ is kept out of heterocysts? 1. If carbohydrates can enter the heterocysts from neighbouring cells via the "intracellular connections," how is it that O₂ doesn't also enter via this route?
2. If the cell walls of Anabaena's photosynthetic cells are permeable to O₂ and CO₂, are they also permeable to N₂?
3. If the nuclei of the photosynthetic cells contain the genes that code for nitrogen fixation, how can these cells fail to perform nitrogen fixation?
4. If the nuclei of the heterocysts contain the genes that code for photosynthesis, how can these cells fail to perform photosynthesis?
5. If the cell walls of Anabaena's heterocysts are permeable to N₂, how is it that N₂ doesn't diffuse out of the heterocysts before it can be fixed?
6. If the thick cell walls of the heterocysts exclude entry of oxygen gas, how is it that they don't also exclude the entry of nitrogen gas?

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

Question 73

Use the information in the following paragraph to answer the next few questions.
A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.
What should be true of the cell wall of this bacterium?

A)Its innermost layer is composed of a phospholipid bilayer.
B)After it has been subjected to Gram staining, the cell should remain purple.
C)It has an outer membrane of lipopolysaccharide.
D)It is mostly composed of a complex, cross-linked polysaccharide.
E)Two of the responses above are correct.

Question 74

Use the information in the following paragraph to answer the next few questions.
A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.
In which feature(s)should one be able to locate a complete chromosome of this bacterium? 1. nucleolus
2. prophage
3. endospore
4. nucleoid

A)4 only
B)1 and 3
C)2 and 3
D)3 and 4
E)2, 3, and 4

Question 75

Use the information in the following paragraph to answer the next few questions.
A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.
Some of the proteins that allow this bacterium to swim are related (in an evolutionary sense)to proteins that

A)attach to the single chromosome.
B)act as restriction enzymes.
C)synthesize peptidoglycan for the cell wall.
D)move penicillin out of the cell.
E)comprise its ribosomes.

Question 76

All of the following are potential causes that may have contributed to the introduction and spread of the infection in the two tanks, with the exception of

A)an infected fish introduced into the tank.
B)crowded conditions.
C)stress/harassment.
D)poor nutrition.
E)uncontaminated water.

Question 77

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following questions.

Which species is probably an important contributor to the base of aquatic food chains as a primary producer?

A)species A
B)species B
C)species C
D)species D
E)species E

Question 78

Use the information in the following paragraph to answer the next few questions.
A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.
This bacterium derives nutrition by digesting human intestinal contents (in other words, food). Thus, this bacterium should be an

A)aerobic chemoheterotroph.
B)aerobic chemoautotroph.
C)anaerobic chemoheterotroph.
D)anaerobic chemoautotroph.

Question 79

Use the information in the following paragraph to answer the next few questions.
A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.
The cell also lacks F factors and F plasmids. Upon its death, this bacterium should be able to participate in

A)conjugation.
B)transduction.
C)transformation.
D)Three of the responses above are correct.
E)Two of the responses above are correct.

Question 80

Use the information in the following paragraph to answer the next few questions.
A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from phagocytes, bacteriophages, and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan.
This bacterium derives nutrition by digesting human intestinal contents (in other words, food). Humans lacking this bacterium have no measurable reproductive advantage or disadvantage relative to humans who harbour this bacterium. Consequently, the bacterium can be properly described as which of the following? 1. symbiont
2. endosymbiont
3. mutualist
4. commensal

A)4 only
B)1 and 2
C)1 and 4
D)2 and 3
E)2 and 4