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1
Q

A bacterial strain lacking the RecA protein will be

A

unable to perform generalized recombination

RecA is involved in generalized recombination. Phase variation is an example of site-specific recombination, which does not require RecA.

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2
Q

A mutation always results in

A

change in genotype

Any change to the DNA sequence results in a change in the genome. Mutations may be beneficial or neutral. A neutral or silent mutation may not affect the phenotype.

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3
Q

An insertion sequence contains a gene for this enzyme

A

Transposase

An insertion sequence (IS) is a simple transposable element that consists of a transposase gene flanked by short, inverted repeats that are the target of transposase.

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4
Q

Avery, MacLeod, and MacCarthy performed landmark experiments showing transformation in which bacterium?

A

Streptococcus pneumoniae

Studies identifying transformation were performed in the 1940s using Streptococcus pneumoniae.

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5
Q

Bacteria may donate DNA to

A

other bacteria of the same or of a different species, some eukaryotic cells, and bacteriophages.

Bacteria can donate DNA to a wide variety of other cells and also viruses. For example, the bacterium Agrobacterium tumefaciens can transfer DNA into plants and phages can acquire bacterial DNA during infection.

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6
Q

Based on gel electrophoresis, a nonfunctional protein is found to have a smaller molecular weight than its wild-type counterpart. A likely explanation for this observation is a

A

nonsense mutation in the DNA coding for the
protein

A nonsense mutation causes a premature stop codon, shortening the protein and lowering its molecular weight. A silent mutation does not change sthe amino acid sequence of the protein. A missense mutation, which replaces one amino acid with another, is unlikely to have a large effect on protein molecular weight. A duplication of the DNA may change the amount of protein being produced, but not its molecular weight.

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7
Q

DNA encoding for which capability is part of the flexible gene pool?

A

Antibiotic resistance

Not all organisms need to contain the genes encoding resistance to specific antibiotics. Genes encoding enzymes involved in DNA replication, ribosome synthesis, and cell membrane synthesis are part of the core gene pool, which consists of genes needed by organisms for independent growth and replication.

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8
Q

During DNA synthesis, if DNA polymerase incorporates a wrong nucleotide,

A

methyl mismatch repair will correct the unmethylated daughter strand to match the methylated template strand.

DNA polymerase is very accurate, but not 100% accurate. Methyl mismatch repair may catch and fix mistakes. The parent strand is methylated and the newly synthesized daughter strand is at first unmethylated, so the unmethylated strand gets repaired.

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9
Q

Horizontal gene transfer can occur via

A

Conjugation, transformation, and transduction can all lead to horizontal gene transfer.

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10
Q

If a bacterial cell is competent, it means that

A

the bacterium can import free DNA fragments and incorporate them into its genome

Competence refers to the ability to perform transformation.

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11
Q

If a bacterial cell is missing AP endonuclease genes, which of the following could NOT occur

A

Base excision repair

AP endonucleases are used during base excision repair, after a glycosylase removes a damaged base, forming an AP site.

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12
Q

If a cytosine deaminates and becomes a uracil, which enzyme will cleave the uracil from the DNA backbone in the first step of a repair process?

A

Glycosylase

Glycosylases remove damaged or wrong bases from the phosphodiester backbone in an early step of base excision repair.

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13
Q

In generalized recombination, which protein complex is responsible for homology searching?

A

RecA

During generalized recombination, the RecA protein complex finds homology and mediates strand invasion.

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14
Q

In the basic Ames test for mutagenesis, a mutagen is tested to see if it can

A

produce colonies on basic medium that lacks
histidine, starting with a hisG mutant strain of bacteria

The Ames test is a reversion test, meaning that the mutagen is tested to see if it can restore the ability to synthesize histidine to hisG mutant bacteria.

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15
Q

One sign of horizontal gene transfer is

A

GC base ratio different from flanking chromosomal DNA

Each type of microorganism has particular GC ratios. Regions of the genome with highly different ratios may be example of genes acquired via horizontal transfer. Uniform codon usage argues against horizontal gene transfer. Gene duplication may occur during replication, but this is not a form of horizontal gene transfer. Gene loss may lead to pathogenicity, but gene loss is not horizontal gene transfer.

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16
Q

Over time, the genome of a species

A

may change due to mutation or gene swapping

Over time, genomes change due to a variety of different mechanisms. Harmful mutations will not persist in a population and although whole genomes may double, this is a rare event.

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17
Q

Pathogenicity islands (PAIs) are often found integrated near

A

tRNA genes

The tRNA genes often serve as sites of PAI integration.

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18
Q

Replicative transposition differs from nonreplicative transposition in that

A

only replicative transposition results in the insertion sequence appearing in new host DNA, while still remaining in the original DNA site

The term “replicative” refers to whether the DNA element is replicated (replicative) or excised and moved (non replicative).

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19
Q

Site-specific recombination

A

needs very little sequence homology between the donor and recipient DNA

Unlike generalized recombination, which requires RecA and large regions of sequence homology, site-specific recombination requires only minimal regions of homology.

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20
Q

The enzyme photolyase repairs DNA damage caused by

A

UV radiation

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21
Q

The mutation rate in a wild-type E. coli cell is on the order
of

A

10^–9 per base pair replicated

The mutation rate in a cell is approximately 10^–9 to 10^–10 per base pair replicated.

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22
Q

The process of importing free DNA from the environment into cells is called

A

transformation

Transformation is the uptake of DNA from the environment. Conjugation requires cell-cell contact, transduction is mediated through a bacteriophage, and transcription is the production of an RNA complementary to a DNA template.

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23
Q

The relaxase enzyme, used during conjugation, has which enzymatic activity?

A

Endonuclease

Relaxase nicks the phosphodiester backbone at oriT site on the fertility factor prior to transfer of a single strand into the recipient cell.

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24
Q

Transduction is an example of

A

horizontal gene transfer

Transduction, the acquisition of a gene from a bacteriophage, is an example of horizontal gene transfer. It does not imply gene duplication, although this may occur. Vertical gene transfer occurs during cellular DNA replication and cell division.

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25
Q

Transposable elements differ from plasmids in that only plasmids

A

may exist autonomously, not integrated into host DNA

Transposable elements may “jump” from one DNA molecule to another, but they do not replicate independently as plasmids can. Both plasmids and transposable elements are comprised of dsDNA and both may code for antibiotic resistance. Conjugative transposons may be transmitted horizontally.

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26
Q

Uptake of foreign DNA into a bacterium

A

may help or harm the bacterium

Bacteria can take up foreign DNA via transformation, conjugation, or transduction. Uptake of foreign DNA may be harmful or helpful depending on what the DNA codes for. For example, uptake of genes that encode useless products drain energy from the bacterium, whereas some plasmids can confer antibiotic resistance, which can be helpful if the bacterium is exposed to that particular antibiotic.

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27
Q

Purines such as guanine are susceptible to spontaneous hydrolysis of the glycosidic bond connecting the base to the sugar backbone. This leads to an apurinic site in a process known as

A

depurination

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28
Q

Which function do bacterial pheromones promote?

A

Conjugation

Pheromones are signaling molecules that help facilitate “bacterial sex,” also known as conjugation.

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29
Q

Which of the following can cause mutations?

A

Chemical mutagens, UV radiation and spontaneous mutations during DNA replication

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30
Q

Which of the following DNA repair mechanisms is error prone?

A

SOS repair

SOS repair, which is error prone, only occurs during extreme DNA damage. Methyl mismatch repair, nucleotide excision repair, and photoreactivation are error proof.

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31
Q

Which of the following enzymes is used in methyl mismatch repair, nucleotide excision repair, and base excision repair?

A

DNA polymerase I

DNA polymerase I is used to synthesize new, correct DNA in all of the repair mechanisms listed. The other enzymes are specific to certain types of repair mechanisms.

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32
Q

Which of the following is a laboratory technique for inducing transformation?

A

Electroporation

Electroporation makes the membrane temporarily permeable to DNA so researcher-supplied DNA can be taken into bacterial cells. The translocasome is involved in natural transformation. Conjugation via sex pili is not a lab technique.

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33
Q

Which of the following is a mutation?

A

A harmful deletion of part of an organism’s DNA

A single base change that enhances fitness

A change in the DNA that does not change protein
structure

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34
Q

Which type of DNA uptake is dependent on transferable plasmids?

A

Conjugation

A transferable plasmid is needed when one cell directly transfers DNA to another cell as occurs in conjugation. Transformation, the uptake of DNA from the environment, and transduction, the acquisition of a gene from a bacteriophage, do not
require a transferable plasmid.

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35
Q

Which type of DNA uptake is dependent on viruses?

A

Transduction

Transduction requires bacteriophages, viruses that infect bacteria, to transfer DNA. Conjugation, the direct transfer of DNA from one bacterial cell to another, and transformation, the uptake of DNA from the environment, do not rely on viruses.

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36
Q

A DNA microchip, scanned with cDNAs, can give information about

A

the transcription of specific genes

Scanning a DNA microchip with cDNAs prepared from mRNAs can give information about which mRNAs were present in the cell.

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37
Q

Accumulation of the heat-shock sigma factor, sigma H, increases at high temperatures because

A

at high temperatures sigma H mRNA adopts an unfolded secondary structure

At normal temperatures the sigma H mRNA adopts a folded secondary structure that hides the ribosome binding site limiting translation. At higher temperatures this secondary structure is lost and the ribosome binding site becomes available.

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38
Q

Acyl homoserine lactone produced by luxI of Allivibrio fisherii is an example of

A

an autoinducer

Acyl homoserine lactone is an autoinducer. High environmental concentrations of the autoinducer lead to transcription of the lux operon, production of luciferase, and bioluminescence.

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39
Q

An inducer causes gene expression by binding

A

a repressor protein to remove it from the DNA

Inducers activate gene transcription by binding a repressor protein and removing the inhibitory repressor from DNA.

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40
Q

Anti-anti-sigma factors

A

bind anti-sigma factors, releasing sigma factors to activate transcription

Anti-anti-sigma factors allow sigma factors to work by binding and inhibiting anti-sigma factors.

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41
Q

AraC is one of a large family of AraC-like proteins. What do all these proteins have in common?

A

They all contain a high degree of homology to AraC and XylS

The AraC-like proteins all contain two helix-turn-helix DNA-binding motifs, although these recognize different consensus sequences. They are not homologous in the ligand-binding domain.

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42
Q

During Bacillus and Clostridium sporulation, transcription is controlled in two different compartments beginning with the use of sigma F. The activity of sigma F is controlled by

A

anti-anti-sigma factors and anti-sigma factors

Sigma F activity is turned on and regulated via anti-sigma and anti-anti-sigma factors and it is degraded by ClpPC protease.

43
Q

During phase variation there is

A

a rearrangement of an organism’s DNA

Phase variation, which changes the amino acid sequence of a protein from one antigenic type to another, involves an alteration in the DNA sequence, often a site-specific recombination that flips a DNA sequence in a chromosome.

44
Q

Enzyme activity can be most rapidly changed at which level?

A

Posttranslational modification of the enzyme

A posttranslational modification to a preexisting protein is the fastest way to change enzyme activity.

45
Q

Guanosine tetraphosphate (ppGpp) serves as a signal to the cell that

A

ribosome synthesis should be curtailed

During poor nutrient conditions, ppGpp accumulates to curtail rRNA and tRNA synthesis. This is known as the stringent response.

46
Q

In attenuation occurring at the trp operon, when will the ribosome pause at the leader sequence?

A

When tryptophan levels are low

The ribosome will pause at the tryptophan codons in the leader sequence under low cell tryptophan levels, when few trp-charged tRNAs are present.

47
Q

One advantage to using sRNAs to control protein expression is that

A

translation of the sRNA is not needed, thus saving amino acids

Because sRNA acts as an RNA and does not need to be translated into protein, it may act more quickly, with less cell energy expenditure. The sRNA does need to be transcribed from DNA and the sRNA will only recognize specific target molecules.

48
Q

Proteins are separated based on electric charge differences during

A

isoelectric focusing gel electrophoresis

During isoelectric focusing proteins in a cell extract are sorted according to their individual charges determined by ionizable amino and carboxyl side groups. SDS- poly acrylamide gel electrophoresis separates proteins based on molecular weight. Electron microscopy is a technique to view subcellular particles. Centrifugation separates cell components based on density, not charge.

49
Q

Quorum sensing may be involved in which of the following processes?

A

Bacterial luciferase expression

Control of bacterial virulence genes

Nitrogen-fixing bacterial symbiosis with plants

50
Q

Some sRNAs are responsible for

A

regulating protein levels at the level of translation

Many sRNA (small untranslated RNAs) are involved in regulating protein levels. The rRNAs form part of the ribosome and tRNAs are charged with amino acids.

51
Q

The AraC-like regulators differ from the LacI repressor in that

A

only the AraC-like regulators can activate transcription by direct interactions with RNA polymerase

The LacI repressor simply comes off DNA in the presence of allolactose, thereby relieving inhibition, whereas AraC-like regulators can actively stimulate transcription by interacting with RNA polymerase.

52
Q

The cAMP receptor protein (CRP) has binding sites for

A

the RNA polymerase alpha subunit

After being bound by cAMP and binding to specific DNA sequences, cAMP-CRP can interact with RNA polymerase to enhance transcription.

53
Q

The DNA sequence 5’-ATCGATCGnnnnnnnnnnCGATCGAT-3’ is an example of

A

an inverted repeat

An inverted repeat is a sequence found in identical (but inverted) forms at two sites on the same double helix. A direct repeat is a sequence found in identical form at two sites on the same double helix (e.g., 5’-ATCGATCGnnnnnATCGATCG-3’). A tandem repeat is a direct repeat without any intervening DNA sequence (e.g., ATCGATCGATCGATCGATCGATCG).

54
Q

The lac operon includes which three proteins?

A

Lactose permease, beta-galactosidase, and thiogalactoside transacetylase

The lac operon contains three genes—lacZ, lacY, and lacA—that encode beta-galactosidase, lactose permease, and thiogalactoside transacetylase, respectively.

55
Q

The lac operon will be maximally transcribed when

A

lactose is present but glucose is not

The lac operon is maximally transcribed when lactose is present as an inducer and glucose is absent to allow binding of cAMP receptor protein (CRP).

56
Q

The protein product of the lacI gene is

A

a regulatory protein

The LacI protein is a repressor, a type of regulatory protein.

57
Q

The proteome refers to the

A

complement of proteins present at a particular point in time

The proteome refers to protein expression patterns. The complement of RNAs is called the transcriptome. The complete set of ORFs simply indicates the number of protein-coding genes but does not describe which ORFs are being transcribed and translated under a given set of conditions.

58
Q

The stringent response

A

occurs in response to low energy stores

The stringent response is a cellular response to idle ribosomes (often indicating low carbon and energy stores) that includes a decrease in rRNA and tRNA production.

59
Q

The trp operon is regulated by

A

both a repressor protein and attenuation

The trp operon has multiple levels of regulation. Both a repressor protein and transcriptional attenuation ensure that the structural genes are only transcribed when tryptophan levels are low.

60
Q

To get maximal expression of the lac operon, low glucose is

A

necessary but not sufficient

Although low glucose is needed, the presence of lactose is also required.

61
Q

What functional group do kinases transfer to other molecules?

A

Phosphate

Kinases phosphorylate other molecules by attaching a phosphate group.

62
Q

When sensing and responding to chemicals, the “key?” protein, CheA, works by

A

lowering CheA activity in the presence of a chemoattractant, which leads to lower CheY-P levels and thus allows for longer runs

CheA is a kinase that will phosphorylate CheY. CheY-P results in higher tumbles. When CheA has lowered activity, CheY is not as phorphrylated and thus, there will be longer runs toward the chemical.

63
Q

Which mechanism sets the levels of a particular protein in the cell?

A

Transcription of DNA into mRNA

Stability of mRNA transcripts

Translation of mRNA into protein

64
Q

Which of the following is composed of DNA?

A

An operator

An operator is a regulatory DNA sequence. Sensor kinases and regulators are proteins. An inducer is a small metabolite that binds to a regulatory protein.

65
Q

Which of the following is LEAST subject to change in the cell?

A

Genome

Although the genome is subject to phase variation, it is the most stable of the omes. The transcriptome changes as different genes are expressed. The proteome changes frequently as different genes are transcribed and translated.

66
Q

Which of the following may indicate a DNA site that binds a regulatory protein?

A

The DNA contains an inverted repeat

Regulatory proteins often function as dimers, which each monomer binding one-half of an inverted repeat.

67
Q

When glucose is present, enzyme IIA^glc is not phosphorylated and LacY is inhibited.

A

The ability of the phosphotransferase system to regulate LacY is known as inducer exclusion. When glucose is present, IIA^glc is not phosphorylated, as it donates its phosphate to glucose. The unphosphorylated IIA^glc inhibits LacY, preventing lactose uptake.

68
Q

Which researchers won a Nobel Prize for discovering that genes can be induced?

A

Jacob and Monod

Jacob and Monod proposed gene regulation in 1961, and along with Lwoff, won the Nobel Prize in Physiology and Medicine in 1965.

69
Q

Which technique can analyze proteome patterns?

A

Two-dimensional gel electrophoresis

Two-dimensional gel electrophoresis can be used to separate proteins. DNA microchip arrays give information about the transcriptome. Polymerase chain reaction is a technique to amplify specific DNA sequences. Enrichment culture is used to grow specific populations of bacteria.

70
Q

A segmented viral genome

A

can facilitate rapid evolution of new viral strains

Since segmented genomes are composed of multiple nucleic acids strands, coinfection with two viral strains can lead to swapping of segments, which may speed up evolution.

71
Q

Compared to bacteriophages, animal viruses usually have an easier time entering cells because

A

animal cells lack a cell wall

The cell wall of bacteria poses problems for phage entry. Animal cells lack a cell wall and thus may ease viral entry. Animal viruses still contact specific membrane proteins to enter.

72
Q

Hepatitis C virus (HCV) is primarily acquired through

A

blood transfusion

HCV is known to cause liver cancer and cirrhosis and it is mainly transmitted by means of blood transfusions and injectable drug usage.

73
Q

Herpes simplex virus (HSV) causes latent infection in the region of the

A

neurons of the ganglia

The primary infection caused by HSV is epithelial in nature. However, it is followed by latent infection within the neurons of the ganglia and in particular the common site of infection is the trigeminal ganglion.

74
Q

Herpes simplex virus (HSV) encodes a proofreading endonuclease that works during viral replication. From this, what can we reasonably predict?

A

The viral mutation rate is relatively low

Proofreading activity implies a low mutation rate. The presence of a viral enzyme implies nothing about whether the host cell can have its own endonuclease. HSV is a double-stranded DNA virus that has a latent phase.

75
Q

Herpes simplex virus (HSV) infects which of the following cell types?

A

Epithelial cells

Ganglial neural cells

76
Q

One reason it is difficult to develop a vaccine for AIDS is because

A

HIV has a high mutation rate

Due to the high error rate of reverse transcriptase, HIV envelope proteins change frequently. This makes vaccine development difficult.

77
Q

Phage T4 protects its genome from cleavage by host restriction endonucleases by

A

modification of cytosines, via hydroxymethylation, in its own genome

A viral enzyme replaces cytosines throughout the phage chromosome with the modified base 5-hydroxymethylcytosine. Restriction endonucleases will not recognize the modified cytosine bases.

78
Q

Retroelements are

A

decaying retroviral genomes in a host genome

Retroelements are decaying retroviral genomes in a host genome.

79
Q

Temperature-sensitive mutations

A

isplay a mutant phenotype at one temperature but not another

Temperature-sensitive mutations are conditional mutations, displaying the mutant phenotype under one environmental condition but not another. Premature stop codons will likely lead to defective proteins regardless of the temperature and temperature-sensitive mutations can be obtained in prokaryotes and viruses.

80
Q

The 5’ internal ribosome entry site (IRES) is present in the genome of

A

Hepatitis C virus (HCV)

IRES segment is present in the genome of HCV. It contains numerous stem loop structures and initiates translation in the host cell.

81
Q

The causative agent of acquired immune deficiency syndrome is

A

Human immunodeficiency virus (HIV)

Human immunodeficiency virus (HIV) is the causative agent of AIDS.

82
Q

The envelope proteins E1 and E2 of Hepatitis C virus (HCV) form dimers, which are

A

club shaped

E1 and E2 are the main envelope proteins that make up the virion. They form a club-shaped dimer structure on the outer surface of the envelope.

83
Q

The following HIV encoded enzymes work in which temporal sequence during an HIV infection?

A

Reverse transcriptase, integrase, protease

A DNA copy of the viral genome is first produced by reverse transcriptase, then integrase inserts the viral genome into the host cell DNA. Finally, viral proteins can be produced and cleaved by protease.

84
Q

The HIV drug azidothymidine (AZT) has what mechanism of action?

A

It is a reverse transcriptase inhibitor

AZT is a nucleotide analog that inhibits reverse transcriptase.

85
Q

The phage T4 infects

A

certain E. coli strains

T4 infects E. coli containing the porin OmpC in their outer membrane.

86
Q

The T4 phage genome contains about how many genes?

A

170

The 166 kilobase T4 genome specifies 170 genes, many of which encode metabolic enzymes that replace host cell functions.

87
Q

The three-dimensional structure of the polyhedral T4 phage was determined in part by

A

X-ray analysis

X-ray crystallography can be used to determine structures. Restriction enzymes cut specific DNA sequences, PCR is used to amplify specific DNA sequences, and two-dimensional gel electrophoresis is used to separate proteins.

88
Q

Viruses that are effective gene therapy vectors should

A

have virulence genes removed

Viruses that are effective gene therapy vectors should have virulence genes removed to avoid patient illness. Promotion of an immune response, integration near an oncogene, and transmission to the germ line should all be avoided.

89
Q

What causes influenza virus hemagglutinin to undergo a structural change that mediates viral envelope fusion with host membranes and viral uncoating?

A

Low pH inside lysosomes

When hemagglutinin is exposed to the low pH inside the lysosome, it triggers conformational changes that allow a fusion peptide to penetrate the lysosomal membrane. This leads to viral uncoating and the release of the viral genome into the cytoplasm.

90
Q

What would happen to an HIV virion that did not include reverse transcriptase due to a packaging error?

A

It would probably be able to enter cells, but would not replicate its genome

Without reverse transcriptase (RT), the virus has no way to produce the double-stranded DNA needed for viral replication. If the HIV envelope glycoproteins are intact, it can enter new cells. RT is not needed for HIV fusion with host cells.

91
Q

Which among the following viruses is the leading cause of mortality in outdoor cats in the United States?

A

Feline leukemia virus

Feline leukemia virus is a major veterinary pathogen that is responsible for killing outdoor cats in the United States. Despite the availability of vaccine, it remains the number one killer.

92
Q

Which enzyme transcribes the integrated HIV genome?

A

Host RNA polymerase

Transcription involves making an RNA copy from a DNA template. RNA polymerase catalyzes this reaction. HIV does not have its own RNA polymerase; it relies on the host polymerase.

93
Q

Which HIV envelope protein is necessary for host cell entry?

A

SU

SU is an envelope protein that initially makes contact with the host cell CD4 protein.

94
Q

Which HIV open reading frame codes for enzymes?

A

pol

The pol open reading frame codes for three enzymes; integrase, RT, and protease. The gag sequence encodes capsid and nucleocapsid proteins and env encodes envelope proteins.

95
Q

Which HIV open reading frame encodes the SU and TM spike proteins?

A

env

The SU (surface) and TM (transmembrane) proteins form spike proteins that peg the envelope. They are encoded by the env open reading frame.

96
Q

Which is true of influenza virus entry into a cell?

A

HA in the viral envelope contacts sialic acid containing proteins in the host membrane.

Hemagglutinin in the viral envelope initially makes contact with sialic acid-containing glycoproteins on the host cell membrane. The virus then undergoes endocytosis and lysosomal fusion.

97
Q

Which of the following enzymes is a potential anti-HIV drug target?

A

Integrase

Protease

Reverse transcriptase

98
Q

Which of the following is an enzymatic activity of reverse transcriptase?

A

DNA synthesis from a DNA template

RT can synthesize DNA from a DNA or an RNA template.

99
Q

Which of the following is one of the two proteins of tight junction to which Hepatitis C virus (HCV) binds?

A

Claudin-1

Claudin-1 and occludinare the two proteins that form a part of the tight junction to which HCV binds and enters into the host cell.

100
Q

Lentiviruses are a type of retrovirus

A

Lentiviruses (such as HIV) are a type of retrovirus, a virus with a single-stranded RNA genome that uses reverse transcriptase to form a double-stranded DNA.

101
Q

Which of the following statements correctly identifies some differences between H5N1 avian influenza and human influenza A?

A

Human influenza A recognizes carbohydrates found in the upper respiratory tract, whereas H5N1 avian influenza only binds carbohydrates deep in the lungs

Human influenza A and H5N1 avian influenza recognize different sialic acid-linked carbohydrates. The carbohydrates recognized by human influenza A are found in the upper respiratory tract, whereas those recognized by H5N1 avian influenza are found deep in the respiratory tract.

102
Q

The influenza envelope proteins are initially synthesized in the endoplasmic reticulum for eventual transport to the cell membrane

A

The influenza envelope proteins ultimately need to be transported to the cell membrane. In eukaryotic cells, cell membrane–bound proteins pass through the endomembrane system consisting of the endoplasmic reticulum (ER) and Golgi.

103
Q

Which of the following viruses contains a DNA genome?

A

Herpes simplex virus

Herpes simplex virus is a DNA virus. All the other viruses listed contain different kinds of RNA genomes.

104
Q

Which of the steps listed is the earliest in the replicative cycle of phage T4?

A

Phage DNA undergoes rolling-circle replication

Of the steps listed, phage replication comes first. After this, late genes are expressed to make head and tail components, genomes are packaged into heads, and heads are assembled onto tails. Lysis of the cell and release of new viral particles is the last step.

General Microbiology (2 decks)

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