Deck 20: Viruses,bacteria,and Archaea

Question 1

Some,but not all,virus capsids are surrounded by

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

Answer 1

A

Question 2

If a virus is latent,it

A)cannot be a retrovirus.
B)is not actively replicating.
C)has not entered a lysogenic cycle.
D)is gaining a new envelope via "budding."
E)is easy to develop immunity against it.

Answer 2

B

Question 3

Consider again the discussion of "properties of life" and describe at least three distinct reasons why viruses are not classified as living organisms.

Answer 3

Answers may vary.The basic unit of life is the cell and all cells come from pre-existing cells.Cells are metabolically active,acquiring,transforming,and using energy.A virus does not qualify as living because it is acellular.Viruses can best be described as nucleic acid surrounded and protected by a protein shell.Cells reproduce either sexually or asexually to form new cells and/or new organisms.Viral components are synthesized during the biosynthesis phase and then assembled in the maturation phase of a virus life cycle.A whole virus does not divide to become new viruses,nor are sex cells produced.Viruses are metabolically inactive unless inside of a host cell.Once inside,nucleic acid replication,transcription and translation may occur,as the host cell's machinery is commandeered by the virus.

Question 4

Pasteur chose the Latin root word for "virus" meaning

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

Question 5

The cycle of viral infection that will rapidly result in the death of a bacterial cell is called the ________ cycle.

A)lysogenic
B)lysozyme
C)lytic
D)lysol
E)lysosome

Question 6

Compare and contrast the lytic and lysogenic cycles.Explain why a virus that follows the lytic cycle is often considered easier to manage.

Question 7

In order to infect a cell,a virus must

A)inject its protein into the cell while the nucleic acid remains attached to the host cell surface.
B)have a special protein on its surface that can interact with a protein on the surface of the host cell.
C)actively burrow through the cell wall or cell membrane of the host cell to reach the cell's nucleus.
D)produce a special extension of its cytoplasm when it comes into contact with the appropriate host cell.

Question 8

All of the following are true about HIV EXCEPT

A)HIV carries RNA as its genetic material.
B)HIV contains an enzyme called reverse transcriptase.
C)HIV must reproduce immediately upon entering a host cell because it cannot survive a latent period.
D)cDNA precedes double-stranded DNA.

Question 9

What is the correct sequence of events in viral reproduction?

A)penetration,attachment,integration,biosynthesis,maturation,release
B)endocytosis,uncoating,maturation,and release
C)attachment,fusion,biosynthesis,maturation,and release
D)attachment,penetration,biosynthesis,maturation and release

Question 10

Which of these is the best description of a virus?

A)a noncellular living organism
B)the smallest bacteria known
C)a member of the kingdom Virusae
D)an invasive cell
E)chemical complexes of RNA or DNA protected by a protein shell

Question 11

Influenza strains that sweep around the world often carry names such as H₅N₁ or H₂N₂.If they are both flu viruses,why do they differ in their H and N numbers?

A)The H and N numbers indicate the geographical region in which the virus was discovered.
B)The H and N numbers indicate the order in which the virus was discovered.
C)The H and N numbers indicate the toxicity of the virus to humans and nonhumans.
D)The H and N numbers indicate the type of glycoprotein spikes found in the viral envelope.

Question 12

Which statement is NOT true about retroviruses?

A)HIV is a retrovirus.
B)They contain an enzyme called reverse transcriptase.
C)They incorporate themselves into the host cell genome,but replicate independently of the host DNA.
D)cDNA is used as a template to transcribe double-stranded DNA.

Question 13

Ivanowsky first recognized that something smaller than a bacterium,called a filterable virus,was able to cause disease in the year

A)1965.
B)2001.
C)1892.
D)1700.
E)1650.

Question 14

Some enveloped animal viruses enter a host cell by

A)injecting their DNA or RNA into the host cell.
B)fusion of their envelope with the host cell's plasma envelope.
C)endocytosis.
D)All of the above.
E)Both B and C.

Question 15

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

A)lysogenic
B)lysozyme
C)lytic
D)lysol
E)lysosome

Question 16

Name the labeled structures of the virus pictured in this figure. A: ________ B: ________
C: ________
D: ________
E: ________

Question 17

What are the two prokaryotic domains?

A)Archaea & Bacteria
B)Eukarya & Bacteria
C)Archaea & Eukarya
D)Protista & Archaea

Question 18

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

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

Question 19

Viruses are categorized according to all of the following EXCEPT

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

Question 20

Describe the lysogenic cycle of a bacteriophage and/or a prophage.Why do you think it would be useful to the virus to have this cycle?

Question 21

Explain the biochemical features that are unique to archaea.

Question 22

Imagine a researcher is trying to genetically engineer this virus so it attacks the lung cells of a human in order to "infect" the host with a particular gene to cure a genetic disorder.Explain which structure the researcher would be most interested in working with in order to get the virus to attack the lung cell of a human.

Question 23

Prokaryotes that require high salt concentrations would be classified as

A)archaeans.
B)bacteria.
C)cyanobacteria.
D)viruses.
E)thermoacidophiles.

Question 24

When conditions are unfavorable,some bacteria form

A)pili.
B)endospores.
C)galls.
D)capsules.
E)thylakoids.

Question 25

Which statement is true about prokaryotes?

A)They contain a nucleus.
B)They lack ribosomes.
C)They usually lack a cell wall.
D)They do not divide by mitosis.
E)They contain a long,linear strand of DNA as the genetic material.

Question 26

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

A)lysogenic
B)sexual
C)lytic
D)alternation of generations

Question 27

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

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

Question 28

The endosymbiotic theory suggests that chloroplasts evolved from cyanobacteria.What features of cyanobacteria support this premise?

Question 29

All of the following are true of methanogens EXCEPT

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 require hot,acidic environments for methanogenesis.

Question 30

Bacteriophages carry portions of bacterial DNA from one cell to another in a process called

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

Question 31

Chemoautotrophs oxidize which of the following to obtain the energy necessary to reduce carbon dioxide to an organic compound?

A)hydrogen gas
B)hydrogen sulfide
C)ammonia
D)nitrites
E)All of the above.

Question 32

Describe how halophiles metabolize nutrients in environments that contain a high salt concentration.

Question 33

Similarities between the archaea and eukarya include

A)the same ribosomal proteins.
B)similar tRNA.
C)similar initiation of transcription.
D)that they are more closely related to each other than to the bacteria.
E)All of the choices are correct similarities.

Question 34

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

A)lysogenic
B)sexual
C)lytic
D)alternation of generations

Question 35

Which group of Archaea are chemoautotrophic anaerobes that use hydrogen as an electron donor and sulfur compounds as terminal electron acceptors?

A)Halophiles
B)Methanogens
C)Thermoacidophiles
D)Cyanobacteria

Question 36

Which description best describes the cell wall of a Gram-positive bacteria?

A)It is composed of a single plasma membrane and a thin outer layer of peptidoglycan.
B)It is composed of a double layer in the plasma membrane and a thin outer layer of peptidoglycan.
C)It is composed of a thick inner layer of peptidoglycan and a double layer of plasma membrane on the outside.
D)It is composed of a single plasma membrane and a thick outer layer of peptidoglycan.
E)It is composed of a single plasma membrane and a thin outer layer of cellulose.

Question 37

Halophiles

A)require a high salt environment.
B)increase the chloride level within their cells.
C)may be chemoheterotrophs or photosynthetic.
D)use bacteriorhodopsin to capture solar energy.
E)All of the choices are correct.

Question 38

Which of the following is a mismatch?

A)thermophiles - live in extremely cold temperatures
B)methanogens - prefer anaerobic environments
C)halophiles - live in high salt environments
D)thermoacidophiles - live in high temperatures and acidic environments

Question 39

All of the following are means of genetic recombination in prokaryotes EXCEPT

A)conjugation.
B)transformation.
C)transduction.
D)crossing over.

Question 40

Prokaryotes generally range in size from

A)10-400 nm.
B)20-300 mm.
C)10-100 µm.
D)1-10 µm.
E)50-100 nm.

Question 41

In your analysis of a newly discovered bacterial species,you find the bacteria reduce carbon dioxide to organic compounds but do not produce oxygen.The nutritional mode of this new bacterial species is most likely

A)oxygenic photoautotroph.
B)anoxygenic chemoautotroph.
C)anoxygenic photoautotroph.
D)oxygenic chemoautotoph.
E)anoxygenic chemoheterotoph.

Question 42

In your analysis of a new bacterial species,you gram stained the bacteria and observed them under the microscope.The bacteria appear to have a round shape and a pink color.Based on this information,you would classify these bacteria as

A)Gram-negative bacilli.
B)Gram-positive spirilli.
C)Gram-negative cocci.
D)Gram-positive bacilli.
E)Gram-positive cocci.

Question 43

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

Question 44

Which of the following characteristics about saprotrophs is NOT true?

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.

Question 45

In an analysis of a new bacterial species,a microbiologist finds that the bacteria has an outer layer comprised primarily of proteins.This layer of proteins is known as a glycocalyx.

Question 46

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

Question 47

Like most eukaryotic animal cells,bacterial cells are diploid.

Question 48

You recently discovered a new photosynthetic bacterial cell.Based on your knowledge of prokaryotes,what else should be present in the cell?

A)mitochondria
B)chloroplasts
C)many infolds of the plasma membrane
D)additional plasmids
E)viral DNA

Question 49

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

Question 50

Explain which features of cyanobacteria enable them to survive in a variety of environments.

Question 51

A prokaryotic cell that contains branched-chain hydrocarbons linked to glycerol belongs to an archaean.

Question 52

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

A)DNA helicase
B)reverse transcriptase
C)DNA ligase
D)reverse helicase

Question 53

Identify the correct sequence of events that occur during the reproduction of HIV.

A)virus attaches to a host cell - the virus enters the cell - viral DNA is incorporated into the host DNA - reverse transcriptase occurs - viral / host DNA is turned into a viral mRNA code - the viral RNA forms into a mature virus - mature viruses leave the host cell
B)virus attaches to a host cell - the virus enters the cell - reverse transcriptase occurs - viral DNA is incorporated into the host DNA - viral / host DNA is turned into a viral mRNA code - the viral RNA forms into a mature virus - mature viruses leave the host cell
C)virus attaches to a host cell - the virus enters the cell - viral DNA is incorporated into the host DNA - reverse transcriptase occurs - the viral RNA forms into a mature virus - viral / host DNA is turned into a viral mRNA code - mature viruses leave the host cell
D)virus attaches to a host cell - the virus enters the cell - viral / host DNA is turned into a viral mRNA code - viral DNA is incorporated into the host DNA - reverse transcriptase occurs - the viral RNA forms into a mature virus - mature viruses leave the host cell

Question 54

You are analyzing some material gathered from a bacterial cell.You find it tests positive for both polysaccharides and amino acids.What part of the bacterial cell did this sample come from?

A)cell wall
B)S-layer
C)glycocalyx
D)nucleoid
E)cell membrane

Question 55

Binary fission is a form of sexual reproduction in which the daughter cells have a different genetic combination than the parent cell.

Question 56

Pasteur's experiments are depicted in this diagram.Do the results of the first experiment confirm the prediction of Hypothesis A or Hypothesis B? Explain.

Question 57

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.

Question 58

Short,bristlelike fibers extending from the surface of a prokaryote are known as

A)flagella.
B)cilia.
C)fimbriae.
D)villi.

Question 59

A lichen is a symbiotic relationship between cyanobacteria and fungi.