Question 1

During which two times can the recipient accurately be described as "recombinant" due to the sequence of events portrayed in Figure 27.2?

Accepted Answer

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 
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 A

Question 2

Regarding prokaryotic genetics, which statement is correct?

Accepted Answer

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. 
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. D

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

Accepted Answer

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

Question 4

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 neighboring cells. Intracellular connections allow heterocysts to transport fixed nitrogen to neighboring 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

Accepted Answer

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

Question 5

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

Accepted Answer

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

Question 6

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

Accepted Answer

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

Question 7

Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains?

Accepted Answer

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 
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 8

Which of the following is least associated with the others?

Accepted Answer

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

Question 9

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

Accepted Answer

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

Question 10

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 neighboring cells. Intracellular connections allow heterocysts to transport fixed nitrogen to neighboring 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 neighboring 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?

Accepted Answer

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

Question 11

The 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.

Accepted Answer

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). 
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 12

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?

Accepted Answer

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? 
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?

Question 13

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

Accepted Answer

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

Question 14

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

Accepted Answer

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. 
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 15

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

Accepted Answer

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

Question 16

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
-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?

Accepted Answer

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 
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 17

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?

Accepted Answer

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 
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 18

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.

Accepted Answer

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 
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 19

Which statement about the domain Archaea is true?

Accepted Answer

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. 
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 20

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

Accepted Answer

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

Exam 27: Bacteria and Archaea

During which two times can the recipient accurately be described as "recombinant" due to the sequence of events portrayed in Figure 27.2?

Regarding prokaryotic genetics, which statement is correct?

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

Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains?

Which of the following is least associated with the others?

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

The 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.

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?

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

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

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?

Which statement about the domain Archaea is true?

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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