Microbiology Chap 13

Front 1

All of the following are characteristics associated with all living things EXCEPT:


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metabolism.
growth.
movement.
reproduction.

Back 1

movement

Front 2

All of the following are general characteristics of viruses EXCEPT:


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they usually contain only nucleic acid and protein.
they are smaller than prokaryotes.
they are acellular microbes.
they are visible by light microscopy.

Back 2

they are visible by light microscopy

Front 3

In the cell, mRNA is produced during the process of _____________ and utilized during the process of _____________.


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transcription; translation
transduction; transformation
translation; transcription
transcription; conjugation

Back 3

transcription; translation

mRNA molecules are produced during transcription of chromosomal genes, and they direct the translation of proteins at ribosomes.

Front 4

The process by which some viruses can inadvertently transfer DNA from one cell to another is called ____________.


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transduction
conjugation
transformation
transposition

Back 4

transduction

Transduction occurs when a viral capsid assembles around fragments of host DNA instead of viral DNA, setting the stage for the transfer of the host DNA to a new cell

Front 5

Lysozyme, an enzyme used by some viruses to attack the peptidoglycan in a bacterial cell, affects which of the following structures?


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DNA
cell wall
ribosomes
cytoplasmic membrane

Back 5

cell wall

Front 6

A viral envelope is a structure composed, primarily, of a phospholipid bilayer. In this respect, a viral envelope is most similar to which of the following?


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the cell wall
bacterial endospores
the cytoplasmic membrane
ribosomes

Back 6

the cytoplasmic membrane

Front 7

The number of effective antiviral drugs available is limited because


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viruses use their hosts' cellular enzymes and structures to replicate.
antiviral drugs cannot enter virus-infected cells.
viruses replicate too quickly to be affected by antiviral drugs.
viruses have different structures than bacterial or animal cells do.

Back 7

viruses use their hosts' cellular enzymes and structures to replicate.

Viruses use the host cell's machinery to replicate, thereby making the selective toxicity necessary for patient treatment difficult.

Front 8

The genome of an organism is its entire


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nucleic acid in the nucleus.
set of active genes.
set of genes.
genetic complement.

Back 8

genetic complement.

The genome of an organism includes its genes as well as the nucleotide sequences that connect the genes to one another - in other words, its complete genetic complement.

Front 9

Which of the following types of cells does NOT have a cell wall?


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fungal cells
animal cells
algal cells
bacterial cells

Back 9

animal cells

Front 10

Most viruses are classified into groups of closely related genera; the taxonomic term for such a group is the __________.


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phylum
family
order
kingdom

Back 10

family

Closely related genera of any organism are grouped into a family.

Front 11

Which of the following scientists was the first to demonstrate that viruses are acellular?


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Ivanowsky
Pasteur
Pauling
Stanley

Back 11

Ivanowsky

In his experiments with infected tobacco plants, Ivanowsky was the first scientist to demonstrate that the cause of tobacco mosaic disease was an acellular infectious agent.

Front 12

The enzyme reverse transcriptase functions by making a(n) __________ copy of a(n) __________ molecule.


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DNA; RNA
DNA; DNA
RNA; DNA
RNA; RNA

Back 12

DNA; RNA

Front 13

Ribosomes are responsible for the production of which of the following molecules?


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tRNA
polypeptides
DNA
mRNA

Back 13

polypeptides

The ribosome, an organelle found in all cells, synthesizes polypeptides from the information in mRNA molecules.

Front 14

A diploid organism has two __________.


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sets of chromosomes
flagella
outer membranes
nuclei

Back 14

sets of chromosomes

Front 15

α-helices and β-pleated sheets are both associated with the structure of which of the following?


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lipids
nucleic acids
carbohydrates
proteins

Back 15

proteins

Front 16

Which of the following is NOT an effective means of sterilization?


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boiling water
autoclaving
incineration
ionizing radiation

Back 16

boiling water

Incineration, autoclaving, and ionizing radiation are all regarded as effective and reliable methods of sterilization. Although boiling water can be a sterilant under certain conditions, it is not generally regarded as an effective means of sterilization.

Front 17

Proteins differ from one another in which of the following ways?


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the types of amino acids used in their structures
the sequence of their amino acids
the types of bonds used to connect their amino acids
the shapes involved in their secondary structure

Back 17

the sequence of their amino acids

All proteins are assembled using the same set of available amino acids, and all use peptide bonds to connect these amino acids together. Furthermore, the secondary structure of a protein is composed of α-helices and β-pleated sheets. However, proteins differ from one another in the exact sequence of amino acids used to create each protein

Front 18

DNA polymerase is necessary for which of the following processes?


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transcription
translation
DNA replication and transcription
DNA replication

Back 18

DNA replication

DNA replication is the process of creating a DNA copy of a DNA template. This process is accomplished by the enzyme DNA polymerase.

Front 19

The process by which an animal cell engulfs a substance using its cytoplasmic membrane is called


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exocytosis.
encephalopathy.
endoflagellum.
endocytosis.

Back 19

endocytosis.

Front 20

Which of the following processes is used to sterilize liquids by merely trapping microbes instead of killing them?


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pasteurization
autoclaving
filtration
incineration

Back 20

filtration

The process of filtration can sterilize a liquid by trapping microbes that are too large to pass through the pores of the filter. Very small microbes such as viruses, however, can often still pass through the filter and become a source of contamination.

Front 21

According to the ICTV scheme of classification, viruses can be classified by a variety of characteristics, including the diseases they cause.
True
False

Back 21

False


According to the ICTV scheme of classification, viruses are classified only by their type of nucleic acid, presence of an envelope, shape, and size.

Front 22

Which of the following types of viruses replicates in the cell's nucleus?

HIV
herpesviruses
rabies viruses
rotaviruses

Back 22

herpesviruses

Herpes and papilloma viruses, among others, are known to replicate in the nucleus of the cell; they have a dsDNA genome very similar to the cell's genome.

Front 23

The _____ replication cycle in bacteriophages results in the death of the cell.

Back 23

lytic

Front 24

Viruses lack all of the following EXCEPT:

a cytoplasmic membrane.
nucleic acid.
cytosol.
organelles.

Back 24

nucleic acid

Front 25

Viruses can specifically infect one type of cell within an organism.
True
False

Back 25

True


Viruses specifically infect only certain types of cells due to their interactions with molecules on the cell surface.

Front 26

Which of the following is a major difference between a lysogenic and a lytic cycle in bacteriophages?

Only lytic cycles can be caused by DNA-containing bacteriophages.
Viral DNA is inserted into the bacterial cell only in a lytic cycle.
The bacteriophage attaches to bacterial surface receptor proteins only in a lysogenic cycle.
Viral DNA becomes a physical part of the bacterial chromosome only in a lysogenic cycle.

Back 26

Viral DNA becomes a physical part of the bacterial chromosome only in a lysogenic cycle.

Front 27

The most common type of polyhedral capsid is a(n) _____

Back 27

icosahedron

icosahedral capsid

Front 28

Which of the following terms refers to a virus in the extracellular state?

nucleocapsid
virion
capsid
bacteriophage

Back 28

virion

Front 29

Bacteriophages outnumber all other life forms.
True
False

Back 29

True


Bacteriophages are more numerous than any cellular form of life

Front 30

Why do viruses have to infect host cells?

They cannot survive outside a host cell.
They are dependent on host cell organelles and enzymes for their replication.
They infect host cells in order to cause tumors.
They infect host cells in order to steal the cell's genome.

Back 30

They are dependent on host cell organelles and enzymes for their replication.

Front 31

A(n) _______ is a membrane that surrounds some viral capsids.

Back 31

envelope (viral envelope)

Front 32

The first virus to be identified was isolated from a

fungus.
human.
bacterium.
plant.

Back 32

plant.

The first virus to be identified was tobacco mosaic virus, which infects tobacco plants.

Front 33

Viruses have genomes of DNA or RNA, but never both.
True
False

Back 33

True


Viruses contain DNA or RNA, but never both

Front 34

Which of the following viruses creates a DNA intermediary molecule from the information in their RNA genomes?

positive-sense ssRNA viruses
negative-sense ssRNA viruses
dsDNA viruses
retroviruses

Back 34

retroviruses

Retroviruses use reverse transcriptase to make a DNA copy of their positive-sense ssRNA genomes

Front 35

The capsid of a virus is made out of which of the following types of molecules?

carbohydrate
lipid
nucleic acid
protein

Back 35

protein

Front 36

Tumors that invade neighboring tissues and travel throughout the body are exhibiting a phenomenon known as _____.

Back 36

metastasis

Front 37

All of the following terms refer to viral shapes EXCEPT:

polyhedral.
helical.
prion.
complex.

Back 37

prion.

Front 38

The _____ stage of the viral life cycle is usually a spontaneous process, although in some viruses it is controlled by enzymes.

Back 38

assembly

Front 39

Proviruses become a permanent part of the host cell's genome.
True
False

Back 39

True


Unlike lysogenic phages, animal viruses that engage in latency produce a provirus that becomes a permanent part of the host cell's genome.

Front 40

The tail fibers of a bacteriophage are most useful during which of the following stages of the lytic replication cycle?

synthesis
attachment
assembly
entry

Back 40

attachment

Bacteriophage tail fibers help the virus attach to receptor proteins on the outside of the target cell.