Deck 17: Evolution of Microbial Life

Question 1

Which statement is least essential in defining a retrovirus?

A)It may insert in many places in the host genome.
B)It contains the enzyme reverse transcriptase.
C)It contains an enzyme to carry out the transcription of RNA to DNA.
D)It contains a genome of RNA.
E)Viral DNA remains in the host genomE.

Answer 1

A
Explanation: The genome of a retrovirus is RNA,not DNA.The virus contains the enzyme reverse transcriptase,which catalyzes the transcription of RNA to DNA.The viral DNA may then remain in the host genome.

Question 2

Which of these is the most accurate description of a virus?

A)a noncellular organism
B)a type of bacteria
C)a member of the Kingdom Virusae
D)a cell at the boundary between living and nonliving things
E)a chemical complex of RNA or DNA protected by protein

Answer 2

E
Explanation: A virus consists essentially of a nucleic acid,either DNA or RNA,protected by a coating of protein.

Question 3

If you were a biologist studying how an RNA virus such as HIV can attack and infect a human cell which contains DNA,you would be studying which of the following enzymes?

A)RNA transcriptase
B)RNA polymerase
C)DNA transcriptase
D)DNA polymerase
E)reverse transcriptase

Answer 3

E
Explanation: HIV,like other retroviruses,has an RNA genome.The virus carries the enzyme reverse transcriptase,which catalyzes transcription of RNA to DNA which can then become integrated with the host cell genome.

Question 4

Which of the following groups of organisms would be used in gene therapy?

A)Bacteria
B)Archaea
C)Viruses
D)Protists
E)Fungi

Question 5

Figure:
This figure shows the basic structure of a virus.What does "c" represent?

A)a spike
B)DNA
C)a capsid
D)a fiber
E)a protein unit

Question 6

If you were studying different diseases and were a microbiologist but not a virologist,which disease would you study?

A)Polio
B)AIDS
C)Smallpox
D)Cervical cancer
E)Chlamydia

Question 7

The capsid of a virus is composed of

A)RNA.
B)protein.
C)DNA.
D)cellulose.
E)lipid.

Question 8

Which of the following is a well known,well established viral disease,rather than an emergent one?

A)SARS
B)Avian influenza
C)Ebola
D)Smallpox
E)West Nile encephalitis

Question 9

Which of the following is the least beneficial role that bacteria play?

A)They function as bioremediators.
B)They are decomposers.
C)They produce antibiotics.
D)They can pigment water.
E)They produce oxygen.

Question 10

Which stage in viral reproduction in found in the lysogenic cycle but not the lytic cycle?

A)penetration
B)biosynthesis
C)integration
D)maturation
E)attachment

Question 11

Which stage of viral reproduction takes place when the DNA and capsids are assembled together?

A)the attachment stage
B)the penetration stage
C)the biosynthesis stage
D)the maturation stage
E)the release stage

Question 12

If you were a biologist studying viruses which are considered to be "naked," what would be missing,compared to a normal virus?

A)an envelope
B)a capsid
C)DNA
D)RNA
E)protein in the inner core

Question 13

When a bacteriophage attaches to a bacterial cell

A)the whole bacteriophage enters the cell.
B)only the capsid coat enters the cell.
C)only the DNA enters the cell.
D)no parts of the bacteriophage enter the cell.
E)only the envelope enters the cell.

Question 14

A biologist is studying the type of bacteriophage reproduction which does not immediately occur,but may take place sometime in the future,called

A)the attachment cycle.
B)the lytic cycle.
C)the maturation cycle.
D)the integration cycle.
E)the lysogenic cyclE.

Question 15

Figure:
This figure shows the basic structure of a virus.What does "a" represent?

A)a spike
B)DNA
C)a capsid
D)a fiber
E)a protein unit

Question 16

Which of the following is the correct order of stages in the lytic cycle?

A)attachment,penetration,biosynthesis,maturation,release
B)attachment,biosynthesis,penetration,maturation,release
C)attachment,maturation,biosynthesis,penetration,release
D)attachment,penetration,maturation,biosynthesis,release
E)attachment,biosynthesis,maturation,penetration,release

Question 17

The innermost core of a virus's structure is made up of

A)a membrane envelope.
B)both DNA and RNA.
C)either DNA or RNA.
D)a protein capsiD.
E)a protein spore coat.

Question 18

Viruses reproduce by

A)conjugation.
B)exchanging gametes.
C)exchanging genes.
D)using the metabolic machinery of the host cell.
E)binary fission.

Question 19

Which of the following true of bacteria rather than viruses?

A)They are noncellular.
B)They are prokaryotic.
C)They can cause disease.
D)They are parasitic.
E)They can have RNA or DNA.

Question 20

Which of the following is least often true about viruses which infect plants?

A)There are approximately 2,000 plant diseases attributed to viruses.
B)Plant viruses kill the host plant outright.
C)The symptoms of plants infected with a virus include stunted growth and a discoloration of leaves.
D)Plant viruses can be spread by contaminated soil or pollen.
E)Plant viruses can be spread via insects and nematodes.

Question 21

If you were writing a paper on Wachtershaüser and Huber's hypothesis on how the first cells arose,your paper would highlight

A)the prion hypothesis.
B)the virus first hypothesis.
C)the facultative anaerobe hypothesis.
D)the prebiotic soup hypothesis.
E)the lysogenic hypothesis.

Question 22

A biologist is studying bacteria which cannot grow in the presence of oxygen,which are called

A)facultative anaerobes.
B)obligate anaerobes.
C)aerobiC.
D)heterotrophic.
E)autotrophic.

Question 23

If you are a biologist studying the chemical composition of the bacterial cell wall,which of the following organic molecules would you find in high concentration?

A)cellulose
B)peptidoglycan
C)chitin
D)proteins
E)ribosomes

Question 24

Bacteria that can grow in the presence or absence of oxygen are called

A)facultative anaerobes.
B)obligate anaerobes.
C)aerobiC.
D)heterotrophic.
E)autotrophic.

Question 25

Which of the following was most likely the first structure that protocells had to have in order to evolve?

A)DNA
B)metabolism
C)photosynthesis
D)a nucleus
E)an outer membrane

Question 26

Which of the following is true for a hypothesis about the origins of life other than the prebiotic soup hypothesis?

A)It hypothesizes that the Earth had a reducing atmosphere.
B)It hypothesizes there was abundant energy.
C)Iron sulfides are needed to facilitate this chemical reaction.
D)It is supported by the works of Miller and Urey.
E)Water vapor,nitrogen,carbon dioxide,and other chemicals were needed to facilitate this chemical reaction.

Question 27

Figure:
This figure is of the basic anatomy of a bacterium.What does "d" represent?

A)nucleoid
B)cell wall
C)ribosome
D)glycocalyx
E)plasma membrane

Question 28

Bacteria reproduce asexually by means of

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

Question 29

A small circle of DNA which can replicate independently of the bacterial chromosome is known as an endospore.

Question 30

Which statement is least accurate about bacteria?

A)They lack mitochondriA.
B)They lack a nucleus but contain DNA.
C)They reproduce sexually by binary fission.
D)There are three basic shapes of bacteria.
E)They have a single circular chromosomE.

Question 31

You are using a microscope to examine a culture of bacteria and you observe that they are all rod shaped.Based on this observation you would conclude that they are

A)cocci.
B)helical.
C)bacilli.
D)rounD.
E)spirilla.

Question 32

Bacteria that live within the root nodules of plants exhibit a type of symbiosis called

A)mutualism.
B)commensalism.
C)parasitism.
D)anaerobic.
E)predation.

Question 33

What is the correct order of stages which must have occurred in evolutionary history for complex cells to have evolved?

A)macromolecules,small organic molecules,protocells,cells
B)small organic molecules,macromolecules,cells,protocells
C)small organic molecules,inorganic chemicals,protocells,cells
D)small organic molecules,macromolecules,protocells,cells
E)macromolecules,inorganic chemicals,cells,protocells

Question 34

If you were studying bacteria which secrete digestive enzymes into the environment to breakdown large organic molecules into smaller ones that can be absorbed,you would be studying which type of bacteria?

A)photoautotrophic
B)saprotrophic
C)
Autosaprobic
D)chemoautotrophic
E)chemoheterotrophic

Question 35

When a bacterium picks up pieces of DNA from its surroundings and makes use of this acquired DNA,it is referred to as

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

Question 36

Based on the work of Thomas Cech and Sidney Altman,why is RNA thought to have been the first type of genetic material?

A)RNA can be both a substrate and an enzyme.
B)RNA is made of nucleotides.
C)RNA is single stranded and more simple than DNA.
D)RNA can be converted into DNA.
E)RNA contains uracil which was abundant in the early atmospherE.

Question 37

When a bacteriophage carries portions of bacterial DNA from one cell to another,this is known as

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

Question 38

If you were a microbiologist studying what happens to some bacteria when faced with unfavorable environmental conditions,you would be studying

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

Question 39

A biologist is studying the exchange of genetic information between two bacteria that are in direct physical contact with one another,a process called

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

Question 40

Figure:
This figure is of the basic anatomy of a bacterium.What does "b" represent?

A)nucleoid
B)cell wall
C)ribosome
D)glycocalyx
E)plasma membrane

Question 41

Which term is related to bacterial reproduction?

A)endospore
B)binary fission
C)conjugation
D)transformation
E)transduction

Question 42

Which of the following statements is true only of bacteria outside the cyanobacteria?

A)They are found in freshwater.
B)They produce oxygen.
C)They fix atmospheric nitrogen.
D)They are considered chemoheterotrophs.
E)They can be associated with fungi to form lichens.

Question 43

The first true cell would have had

A)a membrane only.
B)a nucleic acid only.
C)metabolism only.
D)a membrane and metabolism but no nucleic aciD.
E)a membrane,a nucleic acid,and metabolism.

Question 44

If you were studying archaea which are found in an anaerobic environment such as the mud found in swamps,you would be studying what?

A)halophiles
B)lichens
C)methanogens
D)thermoacidophiles
E)cyanophiles

Question 45

How did the atmosphere of the early Earth differ from that of the Earth today?

A)There was water vapor.
B)There was nitrogen (N₂).
C)There was no oxygen (O₂).
D)There was no carbon dioxide (CO₂).
E)There was no lightning.

Question 46

Which of these is an infectious protein?

A)virus
B)protobiont
C)viroid
D)prokaryote
E)prion

Question 47

Prokaryotes which make their own nutrients with the use of sunlight are referred to as

A)photoautotrophic.
B)saprotrophic.
C)autoheterotrophiC.
D)chemoautotrophic.
E)chemoheterotrophic.

Question 48

Archaea which live in high-salt concentrations are referred to as

A)thermophiles.
B)acidophiles.
C)methanophiles.
D)cyanophiles.
E)halophiles.

Question 49

Viruses and bacteria can be used as biological warfare agents.

Question 50

You have discovered a previously unknown microbe that seems to be associated with a human respiratory infection.It consists only of a strand of RNA covered in a layer of protein,surrounded by a membranous envelope,so it is

A)a bacteriophage.
B)a virus.
C)a viroid.
D)a prion.
E)a bacterium.