Question 1

Due to their indispensible role for copying its genome,an intracellular host protease that attacks the adenoviral protein ends would likely result in halting its replication.

Accepted Answer

Adenovirus requires intact protein ends for genome replication. If an intracellular host protease attacks these ends, replication would be halted.

Question 2

A bacteriophage that lacks its proteinaceous capsid structure is also called a viroid.

Accepted Answer

A bacteriophage without its proteinaceous capsid structure is called a naked or non-enveloped bacteriophage, not a viroid. Viroids are small, single-stranded RNA molecules that infect plants and do not have a protein coat.

Question 3

Some virus shapes that infect members of Archaea are unique from other viruses that infect eukaryotes and bacteria.

Accepted Answer

Some viruses that infect Archaea have unique shapes that are different from viruses that infect eukaryotes and bacteria. This is because Archaea are a separate domain of life with their own distinct cellular structures and processes.

Question 4

A negative-stranded RNA virus produces a complete positive-stranded RNA virus that serves as template DNA for other proteins in order to replicate the complete negative-stranded RNA genome.

Accepted Answer

Negative-stranded RNA viruses must first transcribe their RNA into a positive-stranded RNA, which then serves as a template for protein synthesis and replication of the viral genome, but it does not produce DNA.

Question 5

To date,no virus that infects Archaea is known to have an RNA genome.

Accepted Answer

Viruses that infect Archaea with RNA genomes have been discovered, although they are less common than DNA viruses.

Question 6

Nonfilamentous bacteriophage often can escape its host without lysing,whereas filamentous phage normally induce cell lysis once replicated inside their host.

Accepted Answer

Nonfilamentous bacteriophage usually replicate without causing cell lysis, while filamentous phage release progeny particles through cell lysis.

Question 7

The Baltimore classification scheme is a useful way to categorize viruses based on their host infectivity.

Accepted Answer

The Baltimore classification scheme categorizes viruses based on their method of mRNA production, not their host infectivity.

Question 8

By nature of its infectivity,M13 phage can be used in the laboratory to continually propagate a particular DNA sequence inside of Escherichia coli by simply culturing infected E.coli in LB.

Accepted Answer

M13 phage is a bacteriophage that infects E. coli and can be used to propagate a particular DNA sequence inside of E. coli by culturing infected E. coli in LB. This is because the M13 phage is able to incorporate its DNA into the host E. coli's genome, enabling the continuous propagation of the desired DNA sequence.

Question 9

One hypothesis on the origin of DNA points to RNA viruses evolving a modified nucleotide that is insensitive to ribonucleases.

Accepted Answer

This is one hypothesis, called the RNA World hypothesis, which suggests that RNA viruses evolved a modified nucleotide that was insensitive to ribonucleases, leading to the development of DNA as a more stable genetic material.

Question 10

Varied transcription mechanisms distinguish the different DNA virus Baltimore classes,whereas varied translational mechanisms distinguish RNA viruses.

Accepted Answer

The Baltimore classification system distinguishes viruses based on their replication and transcription mechanisms, not translation. Both DNA and RNA viruses have varied transcription mechanisms, but translation is generally similar across viruses.

Question 11

Bacteriophage that have single-stranded genomes are specialized to minimize energy requirements because just one strand is necessary for replication.

Accepted Answer

Single-stranded genomes do not inherently minimize energy requirements; they require additional steps for replication, such as synthesizing a complementary strand, which can be energy-consuming.

Question 12

Genomics analysis of recently isolated viruses indicate some viruses contain larger genomes than the some bacterial genomes.

Accepted Answer

Through genomics analysis, it has been observed that some viruses, such as pandoraviruses or mimiviruses, have larger genomes than some bacterial genomes.

Question 13

Knowing the genome of Mu bacteriophage now enables researchers to locate where it incorporates into bacterial genomes.

Accepted Answer

Yes, knowing the genome of Mu bacteriophage allows researchers to locate where it incorporates into bacterial genomes as it provides information about the specific sites of integration.

Question 14

Viruses that contain positive-strand genomes are incompatible to share genetic elements other positive-strand genomes.

Accepted Answer

Positive-strand RNA viruses can recombine and share genetic elements with other positive-strand RNA viruses, allowing for genetic diversity and evolution.

Question 15

Many human-infecting viruses that illicit a strong immune response cause additional harmful effects on humans,so the discovery of a virus that can induce an immune response but not cause harm made it attractive for vaccine development.

Accepted Answer

The statement accurately describes the benefits of discovering a virus that can induce an immune response without causing harm. Such a virus is an attractive candidate for vaccine development because it can stimulate an immune response without causing additional harm to the human body.

Question 16

The diversity of genome type and the overall number of bacteriophage that infect Escherichia coli is numerous,but many other bacterial taxa that thrive in the environment are likely infected by a variety of phage as well.

Accepted Answer

This statement is true. Bacteriophages are known to infect a wide range of bacterial taxa, not just Escherichia coli. There is a vast diversity of phage types and it is likely that many other bacteria in the environment are also infected by various types of phage.

Question 17

Despite viruses require a living host's metabolism to replicate,it remains unclear whether viruses existed before living cells.

Accepted Answer

There is no consensus on whether viruses are living organisms or not. Some scientists believe that viruses may have existed before living cells and are remnants of an earlier stage in the evolution of life on Earth. However, this is still a topic of debate and research in the scientific community.

Question 18

Describe how bacteriophages influence the ocean's bacterial populations and nutrient cycling.

Accepted Answer

The answer of Describe how bacteriophages influence the ocean's bacterial...

Question 19

Most archaeal viruses identified appear to have DNA genomes.

Accepted Answer

Most archaeal viruses that have been identified have DNA genomes, although there are some that have RNA genomes or even unusual genome types, such as hybrid RNA-DNA genomes.

Question 20

Due to the genetic diversity of viruses and their lack of ribosomal RNA,nucleotide-based phylogeny studies are not applicable to virology.

Accepted Answer

While it is true that viruses lack ribosomal RNA, nucleotide-based phylogeny studies are still applicable in virology. These studies rely on other conserved regions of viral genomes, such as genes encoding viral polymerases, to establish evolutionary relationships between viruses. Additionally, phylogeny can also be inferred from viral protein sequence data.

Quiz 9: Viral Genomes and Diversity