Only A Genius Can Pass This Microbiology Test! Quiz

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| By Andreazza

Andreazza

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Quizzes Created: 12 | Total Attempts: 7,376

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1/69 Questions

Viruses have typical cellular structure like other living organisms.
- True
- False

About This Quiz

Do you consider yourself a genius when it comes to all things microbiology? The quiz below is designed to test out your theory of being a know it all and whether you do know it all. Take it up and know that only a genius can pass this microbiology test. All the best and do share your certificate as proof.

Only A Genius Can Pass This Microbiology Test! Quiz - Quiz

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2.

Viruses in the extracellular state possess few, if any, active enzymes.
- True
- False
Correct Answer

A. True

Explanation

Viruses in the extracellular state typically do not possess active enzymes. Enzymes are proteins that catalyze various biochemical reactions, and they are essential for the virus to replicate and carry out its life cycle. However, when a virus is outside of a host cell, it is in an inert state and does not actively carry out any metabolic processes. Therefore, it is true that viruses in the extracellular state possess few, if any, active enzymes.

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3.

Which is not true of viruses?
- They can exist in an intracellular or extracellular phase.
- They infect animal and plant cells only.
- They can be observed with an electron microscope.
- They are acellular.
- They replicate only inside host cells
Correct Answer

A. They infect animal and plant cells only.

Explanation

Viruses are acellular and cannot be classified as living organisms as they lack the ability to carry out essential life processes on their own. They can exist in both intracellular and extracellular phases, meaning they can be present inside or outside of host cells. Viruses are too small to be observed with a light microscope, but they can be visualized using an electron microscope. Additionally, viruses are known to infect not only animal and plant cells but also a wide range of other organisms, including bacteria and even other viruses.

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4.

Which of the following is true of viruses in the extracellular phase?
- They possess many different enzymes.
- They can reproduce independently of living cells but only at a slow rate.
- They behave as a macromolecular complex and are no more alive than are ribosomes.
- They possess many different enzymes and they can reproduce independently of living cells but only at a slow rate
Correct Answer

A. They behave as a macromolecular complex and are no more alive than are ribosomes.

Explanation

Viruses in the extracellular phase behave as a macromolecular complex and are no more alive than ribosomes. This means that they do not possess many different enzymes and cannot reproduce independently of living cells. Viruses are considered to be non-living entities because they cannot carry out essential life processes on their own and require a host cell to replicate and function. They are essentially genetic material enclosed in a protein coat and are incapable of metabolism or independent reproduction.

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5.

A complete virus particle is called a
- Capsid.
- Nucleocapsid
- Virion
- Cell
Correct Answer

A. Virion

Explanation

A complete virus particle is called a virion. A virion refers to the fully formed infectious particle of a virus that is capable of infecting a host cell. It consists of a nucleic acid genome (either DNA or RNA) enclosed in a protein coat called a capsid. The capsid protects the viral genome and helps in the recognition and attachment to host cells. Therefore, the term "virion" accurately describes a fully formed and infectious virus particle.

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6.

The nucleic acids carried by viruses usually consist of
- DNA
- RNA
- Either DNA or RNA
- Both DNA and RNA simultaneously
Correct Answer

A. Either DNA or RNA

Explanation

Viruses can have either DNA or RNA as their genetic material. Some viruses have DNA as their genetic material, while others have RNA. This genetic material carries the necessary information for the virus to replicate and infect host cells. The choice between DNA and RNA depends on the specific virus and its replication strategy.

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7.

Which of the following is not true of viruses?
- Viruses are acellular.
- Viruses consist of one or more molecules of DNA or RNA enclosed in a coat of protein and sometimes in other more complex layers.
- Viruses can exist in two phases: intracellular and extracellular.
- Viruses replicate by binary fission.
Correct Answer

A. Viruses replicate by binary fission.

Explanation

Viruses replicate through a process called the lytic cycle, not binary fission. In the lytic cycle, the virus attaches to a host cell, injects its genetic material, takes over the host's cellular machinery to produce more viral components, assembles new viruses, and then bursts the host cell to release the newly formed viruses. Binary fission, on the other hand, is a method of cell division used by bacteria and some single-celled organisms. Therefore, the statement "Viruses replicate by binary fission" is not true.

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8.

Viruses infecting protists, including algae, have never been detected.
- True
- False
Correct Answer

A. False

Explanation

The statement is false because viruses infecting protists, including algae, have been detected. Viruses are known to infect a wide range of organisms, including protists. There have been numerous studies and reports documenting the presence of viruses infecting protists and algae. Therefore, the statement that viruses infecting protists have never been detected is incorrect.

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9.

One way in which small viruses package more information into a very small genome is to use overlapping genes so that the same base sequence is read in more than one reading frame.
- True
- False
Correct Answer

A. True

Explanation

Small viruses are able to package more information into their small genomes by using overlapping genes. This means that the same base sequence is read in more than one reading frame, allowing for multiple genes to be encoded within a single stretch of DNA. This strategy maximizes the genetic information that can be stored in the genome, making it more efficient and compact. Therefore, the statement is true.

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10.

Almost all known plant viruses are RNA viruses.
- True
- False
Correct Answer

A. True

Explanation

This statement is true because the majority of plant viruses that have been identified and studied are RNA viruses. RNA viruses have RNA as their genetic material instead of DNA. These viruses replicate and infect plants by using the host plant's cellular machinery to produce more viral RNA and proteins. Examples of RNA plant viruses include tobacco mosaic virus, potato virus Y, and cucumber mosaic virus. However, it is important to note that new plant viruses are constantly being discovered, so there may be exceptions to this statement in the future.

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11.

Virus morphology does not include which of the following characteristics?
- Size
- Shape
- Presence or absence of an envelope
- Host range
Correct Answer

A. Host range

Explanation

Virus morphology refers to the physical characteristics of a virus. It includes aspects such as size, shape, and the presence or absence of an envelope. However, the host range of a virus refers to the range of different organisms that a virus can infect. This is not a physical characteristic of the virus itself, but rather a characteristic of its ability to infect different hosts. Therefore, host range is not included in virus morphology.

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12.

__________ are glycoprotein spikes protruding from the outer surface of the viral envelope.

Correct Answer
Peplomers

Explanation
Peplomers are glycoprotein spikes that are found on the outer surface of the viral envelope. These spikes play a crucial role in the attachment of the virus to host cells and in facilitating viral entry into the host cell. They are involved in the recognition and binding of specific receptors on the host cell surface, allowing the virus to gain entry and initiate infection. Peplomers are commonly found in enveloped viruses, such as the coronavirus, and are important targets for antiviral therapies and vaccine development.

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13.

Icosahedral viruses are constructed from ring- or knob-shaped units called __________.

Correct Answer
capsomers

Explanation
Icosahedral viruses are made up of ring- or knob-shaped units known as capsomers. These capsomers come together to form the overall structure of the virus.

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14.

Viruses that are polyhedrons with 20 sides are said to have __________ symmetry.

Correct Answer
icosahedral

Explanation
Viruses that have polyhedrons with 20 sides are said to have icosahedral symmetry. Icosahedral symmetry refers to a geometric arrangement in which the virus's structure exhibits 20 identical triangular faces, forming a symmetrical polyhedron. This type of symmetry is commonly found in many viruses, including the rhinovirus and the adenovirus. The icosahedral shape allows the virus to efficiently package its genetic material while maintaining stability and protecting it from external factors.

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15.

The most common capsid morphologies are icosahedral and helical.
- True
- False
Correct Answer

A. True

Explanation

Icosahedral and helical are indeed the most common capsid morphologies. The icosahedral shape is characterized by a symmetrical arrangement of 20 equilateral triangular faces, while the helical shape consists of a spiral arrangement of protein subunits. These two morphologies are commonly observed in viruses and play a crucial role in protecting the viral genetic material. Therefore, the statement "The most common capsid morphologies are icosahedral and helical" is true.

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16.

The largest viruses known are the
- Herpes viruses
- Hepadnaviruses
- Adenoviruses
- Poxviruses
Correct Answer

A. Poxviruses

Explanation

Poxviruses are the largest known viruses. They have complex structures and are capable of infecting a wide range of hosts, including humans. Poxviruses are unique among viruses as they replicate their DNA in the cytoplasm of infected cells, rather than in the nucleus. They are known for causing diseases such as smallpox, which has been eradicated, and other infections that affect both humans and animals. Due to their large size and complex nature, poxviruses have been extensively studied and have played a significant role in advancing our understanding of viral biology and immunology.

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17.

The largest of the viruses are similar in size to some small bacteria and are large enough to be seen with a light microscope.
- True
- False
Correct Answer

A. True

Explanation

Some of the largest viruses are comparable in size to small bacteria and can be observed using a light microscope. This implies that these viruses are significantly larger than most other viruses, which are typically much smaller and require an electron microscope for visualization.

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18.

The presence or absence of an envelope is not useful in classifying viruses because any given virus may at one time have an envelope and at another time not have an envelope.
- True
- False
Correct Answer

A. False

Explanation

The statement explains that the presence or absence of an envelope is not a reliable factor for classifying viruses. This is because a virus can have an envelope at one point in its life cycle and then lose it at another point. Therefore, the presence or absence of an envelope cannot be used as a consistent characteristic for classification.

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19.

Viruses such as MS2 and Qß pack additional information into their genomes through the use of overlapping genes.
- True
- False
Correct Answer

A. True

Explanation

Viruses such as MS2 and Qß are able to pack additional information into their genomes by utilizing overlapping genes. This means that multiple genes can be encoded within the same region of the viral genome, allowing for a more compact and efficient use of genetic material. This mechanism enables these viruses to maximize the amount of genetic information they can carry within their limited genome size. Therefore, the statement "Viruses such as MS2 and Qß pack additional information into their genomes through the use of overlapping genes" is true.

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20.

The simplest viruses consist of
- RNA only
- Protein only
- RNA or DNA in a protein coat
- RNA or DNA in a protein coat covered with lipid envelope
- RNA, DNA and enzymes in a protein coat with a lipid envelope.
Correct Answer

A. RNA or DNA in a protein coat

Explanation

Viruses are infectious agents that can only replicate inside the cells of other organisms. The simplest viruses consist of either RNA or DNA enclosed in a protein coat, also known as a capsid. This capsid provides protection for the genetic material and helps the virus to enter host cells. Some viruses may also have a lipid envelope derived from the host cell membrane surrounding the protein coat. However, the presence of enzymes in the virus structure is not necessary for all viruses, making the option of RNA, DNA, and enzymes in a protein coat with a lipid envelope incorrect.

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21.

Viral capsid protein subunits are called
- Auxomers
- Elastomers
- Protomers
- Viromers
Correct Answer

A. Protomers

Explanation

Viral capsid protein subunits are called protomers. Protomers are individual protein units that make up the viral capsid, which is the outer protein coat of a virus. These protomers come together to form the capsid structure and protect the viral genetic material.

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22.

In an enveloped virus, the part of the virus including the nucleic acid genome and the surrounding protein coat but not the envelope is called the
- Capsid
- Nucleocapsid
- Matrix
- Virion
Correct Answer

A. Nucleocapsid

Explanation

The correct answer is nucleocapsid. In an enveloped virus, the nucleocapsid refers to the part of the virus that includes the nucleic acid genome (such as DNA or RNA) and the surrounding protein coat (capsid). The nucleocapsid is responsible for protecting the viral genome and facilitating its entry into host cells. The envelope, on the other hand, is an outer layer that surrounds the nucleocapsid and is derived from the host cell's membrane.

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23.

Some complex viruses have icosahedral symmetry in the head region and helical symmetry in the tail. Overall, these viruses are said to have __________ symmetry.
- Bilateral
- Binal
- Complex
- None of these
Correct Answer

A. Binal

Explanation

Some complex viruses have a combination of icosahedral symmetry in the head region and helical symmetry in the tail. This means that they have a two-fold symmetry, with two identical halves that are mirror images of each other. The term "binal" is often used to describe this type of symmetry. It is different from bilateral symmetry, which refers to a symmetry with only one plane of symmetry. Complex viruses with binal symmetry have a unique and specific arrangement of their structural components.

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24.

Glycoprotein spikes protruding from the outer surface of viral envelopes function as
- Toxins
- Factors that bind to host cells
- Cell lysis factors
- Factors needed for site specific recombination.
Correct Answer

A. Factors that bind to host cells

Explanation

Glycoprotein spikes protruding from the outer surface of viral envelopes function as factors that bind to host cells. These spikes have specific receptors that allow them to recognize and attach to specific receptors on the surface of host cells. This attachment is crucial for the virus to enter the host cell and initiate infection. By binding to host cells, these glycoprotein spikes facilitate the entry and subsequent replication of the virus within the host organism.

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25.

A __________ genome exists as several separate, nonidentical molecules that may be packaged together or separately.
- Diploid
- Segmented
- Polyploid
- Fractioned
Correct Answer

A. Segmented

Explanation

A segmented genome refers to a genome that exists as several separate, nonidentical molecules. These molecules may be packaged together or separately. This means that the genetic material of the organism is divided into different segments or pieces, rather than being present as a single continuous molecule. This arrangement allows for greater flexibility and variation in the genome, as different segments can be rearranged or exchanged.

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26.

Many of the enzymes found in virus particles are
- Required for viral attachment to host cells.
- Involved in viral entry into host cells.
- Involved in the replication of viral nucleic acid.
- All of the choices
Correct Answer

A. Involved in the replication of viral nucleic acid.

Explanation

The correct answer is "involved in the replication of viral nucleic acid." This is because enzymes are proteins that catalyze chemical reactions, and in the context of viruses, many enzymes play a crucial role in replicating the viral genetic material. These enzymes help in the synthesis of new viral nucleic acid molecules, which is essential for the virus to multiply and spread within host cells. Therefore, all the enzymes found in virus particles are involved in the replication of viral nucleic acid.

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27.

Which of the following is/are not true about viral envelopes?
- The envelope proteins are virus specific.
- The envelope lipids and carbohydrates are derived from the host.
- They are typical lipid monolayers with embedded viral proteins.
- The envelope proteins are virus specific and the envelope lipids and carbohydrates are derived from the host
Correct Answer

A. They are typical lipid monolayers with embedded viral proteins.

Explanation

Viral envelopes are not typical lipid monolayers with embedded viral proteins. This statement is not true because viral envelopes are actually lipid bilayers, not monolayers. The envelope proteins are virus specific and the envelope lipids and carbohydrates are derived from the host.

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28.

Viral envelopes are composed of
- Proteins
- Lipids
- Carbohydrates
- All of the choices
Correct Answer

A. All of the choices

Explanation

Viral envelopes are composed of proteins, lipids, and carbohydrates. This means that all of the given choices are correct. Proteins, lipids, and carbohydrates are the main components of the viral envelope, which is a protective outer layer surrounding the viral particle. These components play important roles in the structure, function, and interaction of the virus with its host cells.

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29.

Two major types of symmetry found in viruses include
- Icosahedral and radial
- Icosahedral and helical
- Helical and radial
- Radial and bilateral
Correct Answer

A. Icosahedral and helical

Explanation

Viruses can exhibit different types of symmetry in their structure. Icosahedral symmetry refers to a symmetrical arrangement of subunits in a virus, forming a roughly spherical shape with 20 identical triangular faces. Helical symmetry, on the other hand, describes a spiral arrangement of subunits, resulting in a cylindrical or rod-like shape. Therefore, the correct answer is "icosahedral and helical" as these are the two major types of symmetry found in viruses.

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30.

The function of the viral protein coat is to
- Protect the viral genetic material
- Aid in the transfer of the viral genetic material between host cells.
- Elicit the production of protective antibodies.
- Protect the viral genetic material and aid in the transfer of the viral genetic material between host cells.
Correct Answer

A. Protect the viral genetic material and aid in the transfer of the viral genetic material between host cells.

Explanation

The viral protein coat serves a dual purpose. Firstly, it protects the viral genetic material from degradation and damage by external factors such as enzymes and harsh environments. Secondly, it aids in the transfer of the viral genetic material between host cells by facilitating the attachment and entry of the virus into the host cell. Therefore, the correct answer is that the viral protein coat protects the viral genetic material and aids in its transfer between host cells.

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31.

The protein coat surrounding the viral genome is called the
- Capsule
- Capsid
- Matrix
- Envelope
Correct Answer

A. Capsid

Explanation

The protein coat surrounding the viral genome is called the capsid. The capsid provides protection to the viral genome and helps in the attachment of the virus to host cells. It is composed of repeating protein subunits called capsomeres, which come together to form the overall structure of the capsid. The capsid plays a crucial role in the life cycle of the virus, as it is responsible for protecting the viral genome during transmission and facilitating the release of the genome into host cells during infection.

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32.

Which of the following is most true of a viral DNA genome?
- It uses the same four nitrogenous bases found in prokaryotic and eukaryotic DNA.
- It may have the normal bases found in prokaryotic and eukaryotic DNA, or it may have one or more unusual bases.
- It is usually composed of unusual bases unique to viruses.
- Viruses do not use DNA for their genome.
Correct Answer

A. It may have the normal bases found in prokaryotic and eukaryotic DNA, or it may have one or more unusual bases.

Explanation

The correct answer is that a viral DNA genome may have the normal bases found in prokaryotic and eukaryotic DNA, or it may have one or more unusual bases. This means that viral DNA can have the same four nitrogenous bases as found in prokaryotic and eukaryotic DNA, or it can have different bases that are unique to viruses. This flexibility allows viruses to adapt and evolve, making them highly diverse and capable of infecting a wide range of hosts.

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33.

Virion size ranges from
- 1–40 nm.
- 10–400 nm.
- 600– 1,000 nm.
- 1,000–10,000 nm.
Correct Answer

A. 10–400 nm.

Explanation

Virion size refers to the size range of viral particles. The correct answer is 10–400 nm. This means that viral particles can vary in size from as small as 10 nanometers to as large as 400 nanometers. Viruses are much smaller than most cells, and their size can vary depending on the specific virus. This size range allows viruses to be small enough to enter and infect host cells, while still containing the genetic material and necessary components for replication and infection.

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34.

Viral capsids are generally constructed without any outside aid once the subunits have been synthesized. This process is called
- Facilitated assembly
- Self-assembly
- Spontaneous maturation
- Self-maturation
Correct Answer

A. Self-assembly

Explanation

Self-assembly is the correct answer because it refers to the process in which viral capsids are constructed without any external assistance once the subunits have been synthesized. This means that the subunits come together on their own to form the capsid structure, without the need for any additional factors or facilitators. This process is a characteristic feature of viral capsid assembly.

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35.

In which of the following stages of the viral infectious cycle do enveloped viruses usually acquire their envelopes?
- Penetration
- Component biosynthesis
- Assembly
- Release
Correct Answer

A. Release

Explanation

Enveloped viruses usually acquire their envelopes during the release stage of the viral infectious cycle. This is when the newly formed viruses are released from the host cell and the envelope is acquired from the host cell's membrane. The envelope is derived from the host cell's membrane and contains viral proteins that are important for the virus's ability to infect new host cells. Therefore, the release stage is crucial for enveloped viruses to acquire their envelopes and continue the infection cycle.

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36.

Most enveloped viruses use the host __________ membrane as their envelope source.
- Plasma
- Nuclear
- Mitochondrial
- None of these
Correct Answer

A. Plasma

Explanation

Enveloped viruses acquire their envelope from the host plasma membrane. This means that the virus takes a piece of the host cell's plasma membrane and incorporates it into its own viral envelope. This allows the virus to evade the immune system and facilitates its entry into new host cells. The viral envelope is important for the virus's ability to infect cells and cause disease.

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37.

Poliovirus receptors are found
- In cells of all tissues
- In spinal cord anterior horn cells only.
- In nasopharynx, gut, and spinal cord anterior horn cells.
- In gut cells only.
Correct Answer

A. In nasopharynx, gut, and spinal cord anterior horn cells.

Explanation

The correct answer is "in nasopharynx, gut, and spinal cord anterior horn cells." Poliovirus receptors are found in these specific locations, indicating that the virus can infect and replicate in cells of the nasopharynx, gut, and spinal cord anterior horn. This suggests that these tissues are vulnerable to poliovirus infection.

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38.

Nonenveloped viruses most often gain access to eukaryotic host cells by
- Fusion with the host cell plasma membrane followed by entrance of the nucleocapsid into the cytoplasm.
- Endocytosis
- Pinocytosis
- Nucleic acid injection through the plasma membrane
Correct Answer

A. Endocytosis

Explanation

Nonenveloped viruses most often gain access to eukaryotic host cells by endocytosis. This process involves the virus being engulfed by the host cell membrane and forming a vesicle called an endosome. The endosome then fuses with lysosomes, which contain enzymes that break down the virus. However, some nonenveloped viruses can escape degradation and release their genetic material into the host cell cytoplasm, leading to infection.

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39.

Which of the following represent(s) the way(s) in which enveloped viruses acquire their envelopes?
- Budding through the plasma membrane.
- Budding through internal cellular membranes.
- Viral enzymes are responsible for production of the envelope.
- For some viruses, a is correct; for other viruses, b is correct.
Correct Answer

A. For some viruses, a is correct; for other viruses, b is correct.

Explanation

Enveloped viruses can acquire their envelopes in two ways: budding through the plasma membrane or budding through internal cellular membranes. This means that some viruses acquire their envelopes by budding through the plasma membrane, while others acquire their envelopes by budding through internal cellular membranes. The answer states that for some viruses, option a is correct, while for other viruses, option b is correct. This suggests that the acquisition of envelopes can vary among different types of enveloped viruses.

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40.

Virus receptors are often not distributed uniformly over the surface of host cells, but are instead concentrated in lipid rafts.
- True
- False
Correct Answer

A. True

Explanation

Virus receptors, which are molecules on the surface of host cells that allow viruses to enter and infect them, are not evenly distributed across the cell surface. Instead, they are often concentrated in specific regions called lipid rafts. These rafts are microdomains within the cell membrane that contain high levels of cholesterol and certain types of lipids. By localizing virus receptors in lipid rafts, the cell can enhance its ability to recognize and interact with viruses, facilitating viral entry and infection. Therefore, the statement "Virus receptors are often not distributed uniformly over the surface of host cells, but are instead concentrated in lipid rafts" is true.

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41.

Enveloped viruses may enter their host cells by fusion of their envelope with the cytoplasmic membrane, thereby depositing their nucleocapsid within the cell.
- True
- False
Correct Answer

A. True

Explanation

Enveloped viruses have an outer envelope made up of lipids, which allows them to fuse with the host cell's membrane. This fusion enables the virus to enter the host cell and release its genetic material (nucleocapsid) into the cell. Therefore, the statement is true.

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42.

Enveloped viruses may enter their host cells by engulfment within coated vesicles (endocytosis).
- True
- False
Correct Answer

A. True

Explanation

Enveloped viruses can enter host cells by being engulfed within coated vesicles through a process called endocytosis. This means that the virus is enclosed in a membrane derived from the host cell, which allows it to enter and infect the cell. This is a common mechanism used by many enveloped viruses to gain entry into their host cells.

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43.

Enveloped viruses may enter their host cells by engulfment within coated vesicles (endocytosis).
- True
- False
Correct Answer

A. True

Explanation

Enveloped viruses are able to enter host cells by being engulfed within coated vesicles through a process called endocytosis. This allows the virus to be enclosed in a membrane-derived vesicle and transported into the cell. Once inside, the virus can then release its genetic material and initiate infection. This mechanism of entry is common among enveloped viruses, which have a lipid envelope surrounding their protein capsid.

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44.

Human cancer causing viruses most often have a ___________ genome.
- SsDNA
- DsDNA
- SsRNA
- DsRNA
Correct Answer

A. DsDNA

Explanation

Human cancer causing viruses most often have a dsDNA genome. This is because dsDNA (double-stranded DNA) is more stable and less prone to mutations compared to other types of genomes such as ssDNA (single-stranded DNA) or RNA genomes. The stability of dsDNA allows the viral genome to be replicated accurately during cell division, reducing the chances of genetic errors that could lead to cancer. Additionally, dsDNA viruses can integrate their genetic material into the host cell's genome, further increasing the risk of cancer development.

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45.

Adult T-cell leukemia is thought to be caused by
- Herpes viruses
- Retroviruses
- Parvoviruses
- Picornaviruses
Correct Answer

A. Retroviruses

Explanation

Adult T-cell leukemia is caused by retroviruses. Retroviruses are a type of RNA virus that can insert a copy of their genome into the DNA of a host cell. In the case of adult T-cell leukemia, the retrovirus involved is called the human T-cell lymphotropic virus type 1 (HTLV-1). HTLV-1 infects T cells, a type of white blood cell, and can lead to the development of adult T-cell leukemia. This virus is primarily transmitted through sexual contact, blood transfusions, and breastfeeding.

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46.

Genes whose expression (or abnormal expression) causes cancer are called
- Cancer genes
- Progenies
- Oncogenes
- Carcinogens
Correct Answer

A. Oncogenes

Explanation

Oncogenes are genes whose expression or abnormal expression causes cancer. These genes play a crucial role in regulating cell growth and division. When oncogenes are activated or mutated, they can promote uncontrolled cell growth and lead to the development of cancer. Understanding oncogenes is important in the field of cancer research and treatment, as targeting these genes can potentially help in developing effective therapies for cancer.

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47.

Which of the following has been associated with a form of liver cancer?
- Human papilloma virus
- Hepatitis B virus
- Human T-cell lymphotropic virus
- Hepatitis A virus
Correct Answer

A. Hepatitis B virus

Explanation

Hepatitis B virus has been associated with a form of liver cancer. Hepatitis B is a viral infection that affects the liver and can lead to chronic liver disease, including cirrhosis and liver cancer. The virus is transmitted through contact with the blood or other body fluids of an infected person. Chronic infection with hepatitis B virus increases the risk of developing hepatocellular carcinoma, which is the most common type of liver cancer. Therefore, hepatitis B virus is the correct answer in this case.

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48.

Microscopic or macroscopic degenerative changes or abnormalities in infected host cells and tissues are called __________ __________.

Correct Answer
cytopathic effects

Explanation
Cytopathic effects refer to the microscopic or macroscopic degenerative changes or abnormalities that occur in infected host cells and tissues. These effects are caused by the infection and can include cell death, changes in cell morphology, and alterations in cellular function.

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49.

In a plaque assay, the number of infectious virions is usually identical to the number of virus particles present.
- True
- False
Correct Answer

A. False

Explanation

In a plaque assay, the number of infectious virions is not always identical to the number of virus particles present. This is because not all virus particles are capable of infecting cells and causing plaque formation. Some virus particles may be defective or unable to successfully enter and replicate within host cells. Therefore, the number of infectious virions can be lower than the total number of virus particles present.

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Mar 21, 2023

Quiz Edited by
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May 25, 2012

Quiz Created by
Andreazza

Only A Genius Can Pass This Microbiology Test! Quiz

Viruses have typical cellular structure like other living organisms.

Quiz Preview

Viruses in the extracellular state possess few, if any, active enzymes.

Which is not true of viruses?

Which of the following is true of viruses in the extracellular phase?

A complete virus particle is called a

The nucleic acids carried by viruses usually consist of

Which of the following is not true of viruses?

Viruses infecting protists, including algae, have never been detected.

One way in which small viruses package more information into a very small genome is to use overlapping genes so that the same base sequence is read in more than one reading frame.

Almost all known plant viruses are RNA viruses.

Virus morphology does not include which of the following characteristics?

__________ are glycoprotein spikes protruding from the outer surface of the viral envelope.

Icosahedral viruses are constructed from ring- or knob-shaped units called __________.

Viruses that are polyhedrons with 20 sides are said to have __________ symmetry.

The most common capsid morphologies are icosahedral and helical.

The largest viruses known are the

The largest of the viruses are similar in size to some small bacteria and are large enough to be seen with a light microscope.

The presence or absence of an envelope is not useful in classifying viruses because any given virus may at one time have an envelope and at another time not have an envelope.

Viruses such as MS2 and Qß pack additional information into their genomes through the use of overlapping genes.

The simplest viruses consist of

Viral capsid protein subunits are called

In an enveloped virus, the part of the virus including the nucleic acid genome and the surrounding protein coat but not the envelope is called the

Some complex viruses have icosahedral symmetry in the head region and helical symmetry in the tail. Overall, these viruses are said to have __________ symmetry.

Glycoprotein spikes protruding from the outer surface of viral envelopes function as

A __________ genome exists as several separate, nonidentical molecules that may be packaged together or separately.

Many of the enzymes found in virus particles are

Which of the following is/are not true about viral envelopes?

Viral envelopes are composed of

Two major types of symmetry found in viruses include

The function of the viral protein coat is to

The protein coat surrounding the viral genome is called the

Which of the following is most true of a viral DNA genome?

Virion size ranges from

Viral capsids are generally constructed without any outside aid once the subunits have been synthesized. This process is called

In which of the following stages of the viral infectious cycle do enveloped viruses usually acquire their envelopes?

Most enveloped viruses use the host __________ membrane as their envelope source.

Poliovirus receptors are found

Nonenveloped viruses most often gain access to eukaryotic host cells by

Which of the following represent(s) the way(s) in which enveloped viruses acquire their envelopes?

Virus receptors are often not distributed uniformly over the surface of host cells, but are instead concentrated in lipid rafts.

Enveloped viruses may enter their host cells by fusion of their envelope with the cytoplasmic membrane, thereby depositing their nucleocapsid within the cell.

Enveloped viruses may enter their host cells by engulfment within coated vesicles (endocytosis).

Enveloped viruses may enter their host cells by engulfment within coated vesicles (endocytosis).

Human cancer causing viruses most often have a ___________ genome.

Adult T-cell leukemia is thought to be caused by

Genes whose expression (or abnormal expression) causes cancer are called

Which of the following has been associated with a form of liver cancer?

Microscopic or macroscopic degenerative changes or abnormalities in infected host cells and tissues are called __________ __________.

In a plaque assay, the number of infectious virions is usually identical to the number of virus particles present.

Microscopic or macroscopic degenerative changes or abnormalities in infected host cells and tissues are called .