Chapter 27: Bacteria & Archaea

Bacteria that _________ tend to have abundant internal membranes. -are photosynthetic -are gram-negative -have flagella -are pathogenic -all of the listed responses are correct

are photosynthetic

The Desulfovibrio bacterium breaks down organic matter (which it must have) and uses sulfate (not oxygen) as an electron acceptor. As a result, it produces hydrogen sulfide (H2S), accounting for the "rotten egg" smell of swamp muck. Oxygen is a deadly poison to Desulfovibrio. We would call Desulfovibrio a(n) __________. -obligately anaerobic chemoheterotroph -facultatively aerobic chemoheterotroph -facultatively anaerobic chemoautotroph -obligately anaerobic chemoautotroph -There is insufficient information to answer this question.

obligately anaerobic chemoheterotroph

Which group of bacteria is unusual in that they lack peptidoglycan in their cell walls? -Chlamydias -Spirochetes -Epsilon proteobacteria -Gram-negative bacteria -Cyanobacteria

Chlamydias

Which subgroup of proteobacteria contains many species that are closely associated with eukaryotic hosts in mutualistic or parasitic relationships? -Alpha -Beta -Gamma -Delta -Epsilon

Alpha

What is the structural feature of gram-positive bacteria that results in their retaining a crystal violet dye stain and thereby being distinguished from gram-negative bacteria in a Gram-stain technique? -Gram-positive bacteria have thicker cell walls. -Gram-positive bacteria lack cell walls. -Gram-positive bacteria lack peptidoglycan in their cell walls. -Gram-positive bacteria have structurally more complex cell walls. -Gram-positive bacteria have additional outer membranes.

Gram-positive bacteria have thicker cell walls

Which of the following is not a true statement concerning bacterial flagella? -Bacterial flagella are homologous to the flagella of eukaryotic cells. -Bacterial flagella are not covered by the plasma membrane as eukaryotic cells are. -There can be more than one flagellum on each bacterial cell. -Bacterial flagella enable bacteria to move. -Bacterial flagella originate in and extend from the cell wall and plasma membrane.

Bacterial flagella are homologous to the flagella of eukaryotic cells

Which of the following statements about cyanobacteria is true? -All of the listed responses are correct. -Some are single cells, whereas others live in filamentous colonies. -They are the only prokaryotes that perform plantlike, oxygenic photosynthesis. -Some species may carry on nitrogen fixation. -It can be said that nitrogen-fixing cyanobacteria are the most self-sufficient of all organisms.

All of the listed responses are correct.

In an experiment, a microbiologist put equal numbers of each of the following organisms into a flask of sterile broth, consisting mostly of sugar and a few amino acids. She then placed the flask in the dark. Which of the following organisms would be most likely to survive? -Chemoheterotrophic bacteria -Cyanobacteria -Photoheterotrophs -Thermoacidophilic bacteria -Photoautotrophs

Chemoheterotrophic bacteria

Which subgroup of proteobacteria contains many species that are predators of other bacteria? -Delta -Alpha -Beta -Gamma -Epsilon

Delta

Which of the following characteristics is a reason why a Gram-stain to distinguish gram-positive from gram-negative bacteria is an important tool in a medical diagnosis of a bacterial infection? -All of the listed characteristics are reasons why a Gram-stain is important in medicine. -The cell walls of many gram-negative bacteria are toxic. -The outer membrane of a gram-negative bacterium helps protect it from the body's defenses. -Certain gram-positive bacteria are resistant to antibiotics. -None of the listed characteristics is a reason why a Gram-stain is important in medicine.

All of the listed characteristics are reasons why a Gram-stain is important in medicine.

Bacteria function primarily in which ecological role? -Bacteria are common in all of the listed ecological roles. -Mutualism -Commensalism -Parasitism -Decomposition

Bacteria are common in all of the listed ecological roles.

Which of the following is a structure that bacteria, archaea, and eukaryotes have? -Plasma membrane -Nuclear envelope -Membrane-enclosed organelles -Peptidoglycan cell wall -Circular chromosome

Plasma membrane

Plasmids __________. -All of the listed responses are correct. -replicate independently of the main chromosome -often contain antibiotic resistance genes -are transferred from one bacterium to another by conjugation -allow bacteria to survive adverse conditions

All of the listed responses are correct.

Which of the following mechanisms is/are (a) means of genetic recombination in prokaryotes? -All of the listed mechanisms are means of genetic recombination. -Transformation -Transduction -Conjugation -None of the listed mechanisms is a means of genetic recombination.

All of the listed mechanisms are means of genetic recombination.

What is the function of a bacterial endospore? -To facilitate persistence in temporarily harsh environments -To adhere to a substrate or other bacteria -To transfer DNA from one cell to another -To fix nitrogen -To store the genetic material of the cell

To facilitate persistence in temporarily harsh environments

Bacteria that use light for their energy source and CO2 for their carbon source are called __________. -photoautotrophs -photoheterotrophs -chemoautotrophs -chemoheterotrophs -photochemoheterotrophs

photoautotrophs

What is a difference between the cell walls of prokaryotes and the cell walls of eukaryotes? -The cell walls of prokaryotes are made of molecules different from those comprising the cell walls of eukaryotes. -There are no cell walls in eukaryotes. -The cell walls of prokaryotes do not play a role in structural support. -The cell walls of prokaryotes do not resist osmotic pressure. -Differences in prokaryotic cell wall composition are difficult to discern in the laboratory.

The cell walls of prokaryotes are made of molecules different from those comprising the cell walls of eukaryotes.

An F+ bacterial cell __________. -acts as a donor during conjugation -acts as a receptor during conjugation -transfers DNA by way of transduction -has many antibiotic resistance genes -uses fimbriae to transfer DNA

acts as a donor during conjugation

Portions of the genomes of certain prokaryotic species are very similar to portions of the genomes of distantly related prokaryotes. The process that most likely accounts for this genetic similarity is __________. -horizontal gene transfer -convergent evolution -identical mutations occurring independently in these distantly related lineages -genetic variation arising from binary fission -genetic variation arising from meiosis

horizontal gene transfer

Antibiotics administered in human medicine work against bacterial infections by __________. -interfering with an aspect of bacterial metabolism or structure that differs from that of eukaryotic cells -providing resources to lure bacteria away from human cells -preventing any cells from dividing -stimulating the host's immune system to mount defenses against the bacteria -raising the host's body temperature to make a less favorable environment for bacteria

interfering with an aspect of bacterial metabolism or structure that differs from that of eukaryotic cells

Acquiring an R plasmid would allow a bacterium to do what? -Resist antibiotics -Reproduce -Conjugate -Reduce its metabolic rate -Resist high temperatures

Resist antibiotics

Some prokaryotes stick to their substrate or to one another by means of hairlike appendages, each called a __________. -fimbria -pilus -capsule -nucleoid -heterocyst

fimbria

Bacterial flagella have a very complex structure composed of 42 distinct proteins. What is the most likely explanation for the evolution of these complex structures? -Exaptation -They evolved from earlier, simpler organisms -Endosymbiosis -Early bacterial species needed to be able to locomote and thus developed complex flagella to facilitate this motility -Flagella evolved as extensions of other bacterial appendages such as pili and fimbriae

Exaptation

Why is salt a good preservative to use for foods such as pork and fish? -Prokaryotic cells living in the food will shrink from their cell walls, impacting their ability to reproduce. -Prokaryotes living in the food products will take in excess water and explode. -Salt is a toxin to prokaryotic cells and leads to their death. -Salt breaks down the chitin contained in the cell walls of prokaryotes. -Salt breaks down the peptidoglycan found in the capsule of prokaryotes.

Prokaryotic cells living in the food will shrink from their cell walls, impacting their ability to reproduce.

Which of the following is not one of the most common prokaryotic cell shapes? -Cuboidal -Spherical -Rod-shaped -Spiral -All of the listed cell shapes are very common.

Cuboidal

Which of the following is a disease caused by bacteria? -Tuberculosis -Common cold -Aids -Smallpox -Measles

Tuberculosis

Prokaryotes found inhabiting the Great Salt Lake would be __________. -extreme halophiles -cyanobacteria -extremophiles -methanogens -extreme thermophiles

extreme halophiles

Which of the following does not contribute to bacteria's ability to evolve rapidly? -Sexual reproduction -Genetic recombination -Large populations -Short generation times -Mutation

Sexual reproduction

Choose the list below that contains the substances required by typical nitrogen-fixing cyanobacteria. -Carbon dioxide, nitrogen, water, light, and some minerals -Oxygen, sulfur, light, water, and some minerals -Carbon dioxide, sulfur, light, water, and some minerals -Carbon, nitrogen, light, water, and some minerals -Carbon dioxide, ammonium, water, light, and some minerals

Carbon dioxide, nitrogen, water, light, and some minerals

What are biofilms? -Biofilms are cooperative colonies of bacteria. -Biofilms are an antibacterial treatment. -Biofilms are any resource upon which bacterial colonies can grow. -A biofilm is the sticky layer surrounding a bacterial cell wall. -A biofilm is a location where nitrogen has been made available in the environment by bacterial decomposition.

Biofilms are cooperative colonies of bacteria.

Which group was not described in Woese's tree of life analysis? -Archaea -Prokarya -Bacteria -Eukarya

Prokarya

What characteristics were used to classify organisms before Woese's tree of life analysis? -Number of cells in the organism -Composition of the cell wall -Presence of a membrane-bound nucleus -Differences in ribosomal RNA sequences

Presence of a membrane-bound nucleus Before the tree of life analysis, organisms were classified as prokaryotes if they lacked a membrane-bound nucleus or eukaryotes if they possessed a membrane-bound nucleus.

True or false? Data showing that the Bacteria were the first lineage to diverge from the common ancestor of all living organisms suggest that the Archaea and Eukarya are more closely related to each other than they are to the Bacteria.

True

Which of the following statements about phylogenetic trees is true? -A paraphyletic group consists of an ancestral population and all of its descendants. -A paraphyletic group has not experienced lateral gene transfer. -A paraphyletic group consists of a common ancestor and some of its descendants. -A monophyletic group consists of a common ancestor and some of its descendants.

A paraphyletic group consists of a common ancestor and some of its descendants. The common characteristics of a paraphyletic group may have arisen from lateral gene transfer to some, but not all, lineages.

Which molecule did Carl Woese study to produce his tree of life? -Ribosome -Messenger RNA -Ribosomal RNA -DNA

Ribosomal RNA Ribosomal RNA was the molecule used to produce Woese's phylogeny because it evolves slowly and is critical to the function of the ribosome, which serves the same function in all three domains in the tree of life.

What is lateral gene transfer? -Inheritance of a gene from a parent -Physical transfer of a gene from a species in one lineage to a species in another lineage. -Inheritance of a gene through meiosis -Inheritance of a gene through mitosis

Physical transfer of a gene from a species in one lineage to a species in another lineage.

Gram-positive Bacteria

Have a thick peptidoglycan layer appear purple after Gram staining alcohol rinse does not remove crystal violet

Gram-negative bacteria

have a thin peptidoglucan layer have an outer membrane as part of their cell wall structure appear pink after Gram staining alcohol rinse easily removes crystal violet

Gram + and Gram - Bacteria

both have a plasma membrane

Nutritional Modes of Bacteria

Autotrophs: require energy only from inorganic sources Chemautotrophs: use chemicals as energy source Photoautotrophs: use light as energy source Heterotrophs: require energy from at least one organic nutrient Chemoheterotrophs: use chemicals as energy sources Photoheterotrophs: use light as energy source Photoheterotrophs & Photoautotrophs --> phototrophs Chemoheterotrophs & Chemoautotrophs --> chemotrophs

Azotobacter is a genus of bacteria that live in soil and have the following characteristics: They are bacilli. They are gram-negative. They are obligate aerobes. They can fix nitrogen. (Unlike some other nitrogen-fixing bacteria, which associate with the roots of plants, Azotobacter species are free-living.) Select the four statements that are true for bacteria in the genus Azotobacter. -They require amino acids or other organic molecules as a source of nitrogen. -They appear purple after Gram staining. -They have a relatively thin layer of peptidoglycan in their cell wall. -They use O2 for cellular respiration. -They are poisoned by O2. -They have the appearance of coils or corkscrews. -They can convert atmospheric nitrogen to ammonia. -They can carry out anaerobic respiration in an environment that lacks O2. -They are shaped like rods.

They have a relatively thin layer of peptidoglycan in their cell wall They use O2 for cellular respiration They can convert atmospheric nitrogen to ammonia They are shaped like rods

You have found a new prokaryote. What line of evidence would support your hypothesis that the organism is a cyanobacterium? -It is able to form colonies and produce oxygen. -It forms chains called mycelia. -It is an endosymbiont. -It lacks cell walls.

It is able to form colonies and produce oxygen.

Which of the following traits do archaeans and bacteria share? -presence of plasma membrane and composition of the cell wall -lack of a nuclear envelope and presence of plasma membrane -composition of the cell wall -composition of the cell wall and lack of a nuclear envelope

lack of a nuclear envelope and presence of plasma membrane

Jams, jellies, preserves, honey, and other foods 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 ____. -are unable to metabolize the glucose or fructose, and thus starve to death -are obligate anaerobes -undergo death as a result of water loss from the cell -are unable to swim through these thick and viscous materials

Prokaryotic cells do not contain which of the following? -DNA -One or more chromosomes -a nuclear membrane -a cell membrane -all of the above

A nuclear membrane

Prokaryotes are a... -Monophyletic group -Paraphyletic group -Polyphyletic group -Oligophyletic group

Paraphyletic group

The transfer of genes from bacteria to eukaryotes is an example of -Vertical gene transfer -Horizontal gene transfer -Conjugation -Transformation

Horizontal gene transfer

Which of the following type of genetic exchange is correctly matched? -via a viral vector: conjugation -direct transfer of DNA between living bacterial cells: transduction -uptake of DNA from the environment: transformation -from parent to offspring: horizontal gene transfer

Uptake of DNA from the environment: transformation

Binary fission is -cell division by meiosis -cell division by simple splitting -cell division by mitosis -exchange of genes between two cells

Cell division by simple splitting

Which of the following describes an orgasnism that obtains energy from sunlight and carbon from CO2? -Chemoheterotroph -Photoheterotroph -Chemoautotroph -Photoautotroph -None of the above

Photoautotroph

Which of the following describes an organism that obtains energy from sunlight and carbon by ingesting prey? -Chemoheterotroph -Photoheterotroph -Chemoautotroph -Photoautotroph -None of the above

Photoheterotroph

Nitrogen Fixation refers to: -the creation of organic molecules that contain nitrogen -the conversion of ammonia (NH3) to N2 -the conversion of N2 to ammonia (NH3) -the radioactive decay of carbon-14 to nitrogen-14

The conversion of N2 to ammonia (NH3)

Which of the following is NOT a characteristic of Archaea? -Possess unique cell membranes with branched hydrocarbons -Prokaryotic -Possess histones -More closely related to bacteria than they are to Eukaryotes

More closely related to bacteria than they are to Eukaryotes

In what type of environment would you find extreme halophiles living? -very salty water -ice -hot springs -anoxic swamps

very salty water

Which of the following statements best describes bacteria? -They are generally harmful -They are limited to living in a few habitats -They are very common in the environment -They are are responsible for diseases in humans like herpes and AIDS

They are very common in the environment

Which of the following is NOT found in the domain Bacteria? -Decomposers -Producers -Pathogens -Mutualistic symbionts -All of the above are found in the domain Bacteria

All of the above are found in the domain Bacteria

Which prokaryote is most likely to cause a photosynthetic bloom? -Proteobacteria -Archaea -Cyanobacteria -Actionobacteria

Cyanobacteria

Which of the following processes release carbon dioxide? -Respiration -Decomoposition -Photosyntehsis -Both respiration and decomposition

Both respiration and decomposition

What proportion of bacteria are pathogenic? -Most of them (>50%) -Some of them (20-50%) -Very few of them (<1%)

Very few of them (<1%)

Bacteria that live in the gut of cows and help digest plant matter are -Mutualistic symbionts -Parasites -Commensalistic symbionts

Multualistic symbionts

Which of the following statement is true? -Bacteria are more closely related to Eukarya than Archaea are -All Archaea are extremephiles -Some bacteria are extremophiles -The exchange of genetic material

Some bacteria are extremophiles