Question 1

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

Accepted Answer

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

Question 2

Which of these statements about prokaryotes is correct?

Accepted Answer

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. 
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 3

The following questions refer to Figure 27.1.
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.
   
Figure 27.1
-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

Accepted Answer

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

Question 4

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?

Accepted Answer

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. 
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 5

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?

Accepted Answer

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. 
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 6

Which statement about bacterial cell walls is false?

Accepted Answer

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. 
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 7

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

Accepted Answer

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

Question 8

Which question, arising from the results depicted in Figure 27.2, is most interesting from a genetic perspective, and has the greatest potential to increase our knowledge base?

Accepted Answer

A)  If reciprocal crossing over could occur even if the piece of donated Hfr DNA is 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? 
A)  If reciprocal crossing over could occur even if the piece of donated Hfr DNA is 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 9

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

Accepted Answer

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 
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 10

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?

Accepted Answer

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

Question 11

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

Accepted Answer

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

Question 12

The following questions refer to Figure 27.1.
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.
   
Figure 27.1
-If the vertical axis of Figure 27.1 refers to "Darwinian fitness," then which of the following is the most valid and accurate measure of fitness?

Accepted Answer

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 
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 13

Plantlike photosynthesis that releases O₂ occurs in

Accepted Answer

A)  cyanobacteria. 
B)  chlamydias. 
C)  archaea. 
D)  actinomycetes. 
E)  chemoautotrophic bacteria. 
A)  cyanobacteria. 
B)  chlamydias. 
C)  archaea. 
D)  actinomycetes. 
E)  chemoautotrophic bacteria.

Question 14

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

Accepted Answer

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. 
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 15

Figure 27.2 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 Figure 27.2 to answer the following questions.
   
Figure 27.2
-What is occurring at Time C that is decreasing the DNA content?

Accepted Answer

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 
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 16

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

Accepted Answer

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

Question 17

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

Accepted Answer

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

Question 18

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

Accepted Answer

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. 
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.

Question 19

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)?

Accepted Answer

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

Question 20

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?

Accepted Answer

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

Exam 27: Bacteria and Archaea

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

Which of these statements about prokaryotes is correct?

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?

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?

Which statement about bacterial cell walls is false?

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

Which question, arising from the results depicted in Figure 27.2, is most interesting from a genetic perspective, and has the greatest potential to increase our knowledge base?

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?

Plantlike photosynthesis that releases O₂ occurs in

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

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

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

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

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)?

Introduction: Themes in the Study of Life

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

The Molecular Basis of Inheritance

From Gene to Protein

Regulation of Gene Expression

Viruses

Biotechnology

Genomes and Their Evolution

Descent with Modification: A Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Protists

Plant Diversity I: How Plants Colonized Land

Plant Diversity II: The Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signaling

Nervous Systems

Sensory and Motor Mechanisms

Animal Behavior

An Introduction to Ecology and the Biosphere

Population Ecology

Community Ecology

Ecosystems and Restoration Ecology

Conservation Biology and Global Change

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