Question 1

Refer to the figure, which shows the phylogenetic tree of major groups of living organisms.  Based on the figure, which statement about the endosymbiotic origin of eukaryotic mitochondria is true?

Accepted Answer

A)  Mitochondria are derived from endosymbiotic bacteria. 
B)  The common ancestor of Archaea and Eukarya possessed mitochondria. 
C)  Some prokaryotic archaea possess mitochondria. 
D)  Mammals possess chloroplasts, which become functional during starvation. 
E)  Bacteria is more closely related to Eukarya than to Archaea.

Question 2

Gram-negative, rod-shaped bacteria

Accepted Answer

A)  are all closely related. 
B)  include Escherichia coli. 
C)  can reproduce only within the cells of other organisms. 
D)  all possess structures called axial filaments. 
E)  include the important genera Bacillus and Clostridium.

Question 3

Which of the following is a broad nutritional category of prokaryotes that is recognized by biologists?

Accepted Answer

A)  Physioautotrophs 
B)  Heteroautotrophs 
C)  Chemoautotrophs 
D)  Heterophysiotrophs 
E)  Chemophysiotrophs

Question 4

Hundreds of different antibiotics are produced by members of the genus

Accepted Answer

A)  Mycobacterium. 
B)  Bacillus. 
C)  Clostridium. 
D)  Streptomyces. 
E)  Staphylococcus.

Question 5

Ninety percent of the cells in the human body are microbes-mostly prokaryotes and some microscopic eukaryotes.Which statement about human microbiomes is true?

Accepted Answer

A)  Uniform communities of well-characterized bacterial species cover every surface of the human body. 
B)  Diseases in which our immune systems begin to attack our bodies have been linked increasingly to the changing diversity and composition of our microbiomes. 
C)  Human health depends on ridding the body of all microbes, both on the inside of the body and on the outside. 
D)  Human microbiomes are composed primarily of prokaryotic extremophiles. 
E)  Biofilms produced by human microbiomes are always beneficial to their hosts.

Question 6

Many Gram-negative bacteria that cause disease have _______ composed of lipopolysaccharides, which can cause fever and vomiting when the bacteria burst.

Accepted Answer

The answer of Many Gram-negative bacteria that cause disease have...

Question 7

Refer to the figure.  Label the three basic shapes of bacteria shown.

Accepted Answer

The answer of Refer to the figure.  Label the...

Question 8

When building phylogenetic trees, scientists approach the task by using single gene sequences, multiple gene sequences, or _______ gene sequences.

Accepted Answer

The answer of When building phylogenetic trees, scientists approach the...

Question 9

A strain of heat-tolerant pathogenic bacteria has acquired resistance to all known antibiotics.Which method would you propose to best control its future spread?

Accepted Answer

A)  The introduction of nonpathogenic bacteria to compete with the pathogen for resources. 
B)  The introduction of a bacteriophage that is known to attack a closely related bacterial species. 
C)  Heat sterilization of affected areas. 
D)  The development of a new class of antibiotics that the pathogen has not yet encountered. 
E)  The development and application of metabolically inactive nutrient analogues.

Question 10

Prokaryotic cells do not possess

Accepted Answer

A)  DNA. 
B)  RNA. 
C)  enzymes for transcription and translation. 
D)  a system for generating ATP. 
E)  an immune system.

Question 11

Which statement about peptidoglycan is true?

Accepted Answer

A)  It is present in the cell walls of almost all bacteria. 
B)  It is present in the cell walls of archaea. 
C)  It is present in larger amounts in the cell walls of Gram-negative bacteria than in the cell walls of Gram-positive bacteria. 
D)  Its synthesis is unaffected by penicillin. 
E)  It is present in the cell walls of yeasts.

Question 12

Bioluminescence

Accepted Answer

A)  can be bright enough to be detected from space. 
B)  occurs only in prokaryotes. 
C)  has no known function in prokaryotes. 
D)  occurs only in marine organisms. 
E)  does not require energy.

Question 13

Some biologists do not consider viruses to be a form of life because they

Accepted Answer

A)  use the same essential forms of genetic information storage and transmission as do cellular organisms. 
B)  infect all cellular forms of life. 
C)  replicate, mutate, evolve, and interact with other organisms. 
D)  are highly diverse. 
E)  depend on cellular organisms for basic life functions, such as replication and metabolism.

Question 14

Medications and environmental influences that destroy numerous microbes in the human body would

Accepted Answer

A)  promote good health. 
B)  prevent all infections. 
C)  likely be injurious to human health. 
D)  affect only pathogenic bacteria. 
E)  result in fewer autoimmune diseases.

Question 15

Which of the following is not a reason that ribosomal RNA is useful for studying the evolutionary relationships among living organisms?

Accepted Answer

A)  Ribosomal RNA undergoes a high degree of lateral transfer. 
B)  No free-living organism lacks ribosomal RNA. 
C)  Ribosomal RNA plays a critical role in the translation process in all organisms. 
D)  Ribosomal RNA evolves slowly, so it can be analyzed across a wide range of organisms. 
E)  Ribosomal RNA is evolutionarily ancient and was present in the common ancestor of all life forms.

Question 16

Viruses are difficult to control with antiviral medications, because

Accepted Answer

A)  their evolutionary relationships are difficult to trace. 
B)  heritable alterations to their genomes occur frequently. 
C)  they are relatively primitive microbes. 
D)  they have a protein coat. 
E)  they are infectious agents.

Question 17

The genetic makeup of many viruses supports the hypothesis that they are derived from "escaped" cellular components.Judging from its genetic makeup, the virus most likely derived from an "escaped" cellular component is a

Accepted Answer

A)  provirus. 
B)  mimivirus. 
C)  single-stranded RNA virus. 
D)  double-stranded RNA virus. 
E)  double-stranded DNA virus.

Question 18

Bacteria that lack cell walls, are mostly plant and animal parasites, and are among the smallest cellular creatures are

Accepted Answer

A)  cyanobacteria. 
B)  spirochetes. 
C)  chlamydias. 
D)  actinobacteria. 
E)  mycoplasmas.

Question 19

Refer to the figure, which shows a variety of viruses.  According to the figure, which statement about viruses is true?

Accepted Answer

A)  Double-stranded DNA viruses all have a spherical shape. 
B)  The retrovirus that causes AIDS is similar in shape to the virus that causes SARS. 
C)  Viruses that infect bacteria attach to host cells in different ways than viruses that cause the flu in humans. 
D)  Negative-sense single-stranded RNA viruses have a rod-like shape. 
E)  DNA mimiviruses are among the smallest types of virus.

Question 20

Which of the following is not one of Koch's postulates for determining whether a particular microorganism causes a particular disease?

Accepted Answer

A)  The microorganism is always found in the diseased individual. 
B)  The microorganism taken from the diseased host can be grown in pure culture. 
C)  A sample of the pure culture of the microorganism produces the disease when it is injected into an uninfected host. 
D)  A host infected by injection from the cultured microorganism yields a new culture of the microorganism identical to the original culture. 
E)  A host infected by the microorganism can infect another organism by transmission of the microorganism through an insect vector.

Exam 25: Bacteria, Archaea, and Viruses

Refer to the figure, which shows the phylogenetic tree of major groups of living organisms. Based on the figure, which statement about the endosymbiotic origin of eukaryotic mitochondria is true?