Question 1

Which of these is the best description of a virus?

Accepted Answer

A)  a noncellular living organism
B)  one of the smallest bacteria known
C)  a member of the kingdom Virusae
D)  a cell at the boundary between living and nonliving things
E)  chemical complexes of RNA or DNA protected by protein shellF) A) and E)
G) A) and B)

Question 2

Prokaryotes are now divided into the

Accepted Answer

A)  archaea and bacteria.
B)  bacteria and cyanobacteria.
C)  photosynthetic bacteria and chemosynthetic bacteria.
D)  archaea and cyanobacteria.
E)  autotrophs and heterotrophs.F) All of the above
G) A) and E)

Question 3

A facultative anaerobe is an organism that can metabolize effectively in the presence or absence of oxygen.

Accepted Answer

A) True 
 B)False

Question 4

Which of the following characteristics about saprotrophs is NOT true?

Accepted Answer

A)  They are viruses that infect plant and fungal cells.
B)  They are bacteria that decompose large organic molecules.
C)  Saprotrophs are also called decomposers.
D)  They are ecologically important in recycling matter.E) All of the above
F) B) and C)

Question 5

Bacterial cells pick up free pieces of DNA that were secreted by live bacteria or released from dead bacteria in their environment.This process is called

Accepted Answer

A)  transformation.
B)  transduction.
C)  conjugation.
D)  infection.
E)  replication.F) B) and E)
G) C) and D)

Question 6

Some,but not all,virus capsids are surrounded by _________.

Accepted Answer

A)  a membranous envelope
B)  both DNA and RNA
C)  either DNA or RNA
D)  a protein capsid
E)  a protein spore coatF) A) and C)
G) B) and E)

Question 7

The innermost portion of a virus' structure is made up of

Accepted Answer

A)  a membranous envelope.
B)  either DNA or RNA.
C)  both DNA and RNA.
D)  a protein capsid.
E)  spikes.F) A) and B)
G) A) and C)

Question 8

Study the life cycle diagram.Label B is the ________ life cycle.

Accepted Answer

A)  lysogenic
B)  sexual
C)  lytic
D)  alternation of generationsE) B) and C)
F) A) and C)

Question 9

All of the following are true of methanogens EXCEPT

Accepted Answer

A)  they produce methane from CO2 and H2.
B)  they live in the intestinal tracts of cows,humans,and termites.
C)  they live in swamps and marshes.
D)  their biogas may contribute to global warming.
E)  they are harmful human pathogens.F) A) and C)
G) B) and E)

Question 10

Similarities between the archaea and eukarya include

Accepted Answer

A)  same ribosomal proteins.
B)  similar tRNA.
C)  similar initiation of transcription.
D)  All of the choices are correct similarities.
E)  same ribosomal proteins and different initiation of transcription.F) A) and D)
G) All of the above

Question 11

An environmental change,such as exposure to ultraviolet light,may cause a lysogenic bacterium to enter a lytic cycle.

Accepted Answer

A) True 
 B)False

Question 12

Pasteur chose the Latin root word for "virus" meaning

Accepted Answer

A)  extremely small.
B)  non-living.
C)  poison.
D)  contagious.
E)  particle.F) B) and E)
G) D) and E)

Question 13

Eukarya are believed to have diverged from the bacterial line of descent.The Eukarya are,therefore,more closely related to the Bacteria than to the Archaea.

Accepted Answer

A) True 
 B)False

Question 14

What is the correct sequence of events in the lytic cycle of a bacteriophage infection?

Accepted Answer

A)  Attachment,Viral DNA penetration into host cell,Integration of viral DNA into host cell DNA,Biosythesis,Maturation,Release
B)  Endocytosis of virion,Uncoating,Maturation,and Release
C)  Attachment,Fusion of envelope and host cell membrane,Biosynthesis,Maturation,and Release
D)  Attachment,Viral DNA penetration,Biosynthesis,Maturation and ReleaseE) B) and D)
F) A) and D)

Question 15

Halophiles

Accepted Answer

A)  Require a high salt environment.
B)  Have a chloride pump that pumps chloride into the cell.
C)  May be chemoheterotrophs or photosynthetic.
D)  All of the above choices are correct.
E)  Require a high temperature in order to surviveF) A) and B)
G) A) and E)

Question 16

Viruses are categorized according to all of the following EXCEPT

Accepted Answer

A)  size and shape.
B)  their type of nucleic acid.
C)  the presence of absence of an envelope.
D)  their method of reproduction,whether asexual or sexual.E) A) and D)
F) C) and D)

Question 17

An enveloped virus enters a host cell by

Accepted Answer

A)  injecting its DNA or RNA into the host cell.
B)  fusion of its envelope with the host cell's plasma envelope.
C)  endocytosis.
D)  Any of the above choices are correct.
E)  Attaching to the host cell's membrane and then injecting its DNA or RNA into the host cell.F) A) and B)
G) B) and E)

Question 18

The cycle of viral infection in which the viral DNA is integrated into the host's DNA is called the _______ cycle.

Accepted Answer

A)  lysogenic
B)  lysozyme
C)  lytic
D)  lysol
E)  lysosomeF) B) and C)
G) A) and C)

Question 19

Which enzyme enables a retrovirus to convert its' RNA genome into DNA?

Accepted Answer

A)  DNA helicase
B)  reverse transcriptase
C)  DNA ligase
D)  reverse helicaseE) A) and D)
F) A) and C)

Question 20

A Gram-negative bacteria will have a peptidoglycan layer that is sandwiched between two plasma membranes and will stain purple.

Accepted Answer

A) True 
 B)False

Exam 20: Viruses,bacteria,and Archaea

Which of these is the best description of a virus?

Correct AnswerverifiedShow Answer

What is the correct sequence of events in the lytic cycle of a bacteriophage infection?

Correct AnswerverifiedShow Answer

Which enzyme enables a retrovirus to convert its' RNA genome into DNA?

Correct AnswerverifiedShow Answer

A Gram-negative bacteria will have a peptidoglycan layer that is sandwiched between two plasma membranes and will stain purple.

Correct AnswerverifiedShow Answer

Eukarya are believed to have diverged from the bacterial line of descent.The Eukarya are,therefore,more closely related to the Bacteria than to the Archaea.

Correct AnswerverifiedShow Answer

Some,but not all,virus capsids are surrounded by _________.

Correct AnswerverifiedShow Answer

Study the life cycle diagram.Label B is the ________ life cycle.

Correct AnswerverifiedShow Answer

Pasteur chose the Latin root word for "virus" meaning

Correct AnswerverifiedShow Answer

All of the following are true of methanogens EXCEPT

Correct AnswerverifiedShow Answer

Similarities between the archaea and eukarya include

Correct AnswerverifiedShow Answer

Prokaryotes are now divided into the

Correct AnswerverifiedShow Answer

An enveloped virus enters a host cell by

Correct AnswerverifiedShow Answer

A facultative anaerobe is an organism that can metabolize effectively in the presence or absence of oxygen.

Correct AnswerverifiedShow Answer

The cycle of viral infection in which the viral DNA is integrated into the host's DNA is called the _______ cycle.

Correct AnswerverifiedShow Answer

The innermost portion of a virus' structure is made up of

Correct AnswerverifiedShow Answer

Viruses are categorized according to all of the following EXCEPT

Correct AnswerverifiedShow Answer

Halophiles

Correct AnswerverifiedShow Answer

An environmental change,such as exposure to ultraviolet light,may cause a lysogenic bacterium to enter a lytic cycle.

Correct AnswerverifiedShow Answer

Which of the following characteristics about saprotrophs is NOT true?

Correct AnswerverifiedShow Answer

Bacterial cells pick up free pieces of DNA that were secreted by live bacteria or released from dead bacteria in their environment.This process is called

Correct AnswerverifiedShow Answer

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