Podcast
Questions and Answers
Which characteristic distinguishes viruses from cellular organisms?
Which characteristic distinguishes viruses from cellular organisms?
- Obligate intracellular parasitic nature.
- Containing either DNA or RNA, but not both. (correct)
- Ability to infect both eukaryotes and prokaryotes.
- Presence of a capsid structure.
A newly discovered virus has a complex capsid structure that is neither purely helical nor icosahedral. Which type of virus is this most likely to be?
A newly discovered virus has a complex capsid structure that is neither purely helical nor icosahedral. Which type of virus is this most likely to be?
- Complex virus (correct)
- Enveloped virus
- Icosahedral virus
- Helical virus
If a virus is described as 'enveloped', what structural feature does it possess?
If a virus is described as 'enveloped', what structural feature does it possess?
- A three-dimensional capsid with triangular faces.
- A capsid made of helical capsomeres.
- A surrounding membrane external to the capsid. (correct)
- Long projections extending from the nucleocapsid.
Which of the following best describes the function of the 'spike' structures found on some viruses?
Which of the following best describes the function of the 'spike' structures found on some viruses?
A virus has been identified with a linear RNA genome. Which classification is least likely for this virus?
A virus has been identified with a linear RNA genome. Which classification is least likely for this virus?
What is the primary role of the viral capsid?
What is the primary role of the viral capsid?
A virologist is studying a bacteriophage. What type of cell does this virus infect?
A virologist is studying a bacteriophage. What type of cell does this virus infect?
Which of the following characteristics is NOT used to classify viruses?
Which of the following characteristics is NOT used to classify viruses?
What term describes the combination of a viral capsid and its enclosed nucleic acid?
What term describes the combination of a viral capsid and its enclosed nucleic acid?
How do reverse transcribing viruses differ from other viruses in their replication strategy?
How do reverse transcribing viruses differ from other viruses in their replication strategy?
A researcher observes a virus under an electron microscope and notes that its capsid is rod-shaped. Which type of virus is this?
A researcher observes a virus under an electron microscope and notes that its capsid is rod-shaped. Which type of virus is this?
Which viral component is responsible for the initial attachment to host cells?
Which viral component is responsible for the initial attachment to host cells?
What is a key difference between naked and enveloped helical viruses?
What is a key difference between naked and enveloped helical viruses?
Which type of nucleic acid arrangement is possible in viruses?
Which type of nucleic acid arrangement is possible in viruses?
How does the replication strategy of Cytomegalovirus differ from that of most other DNA viruses?
How does the replication strategy of Cytomegalovirus differ from that of most other DNA viruses?
Which of the following is a characteristic feature of complex viruses such as bacteriophages?
Which of the following is a characteristic feature of complex viruses such as bacteriophages?
Which viral structure is directly involved in the transfer of viral nucleic acid into the host cell during infection by a bacteriophage?
Which viral structure is directly involved in the transfer of viral nucleic acid into the host cell during infection by a bacteriophage?
What is the significance of classifying viruses based on their morphology?
What is the significance of classifying viruses based on their morphology?
Considering the size range of viruses, what implication does this have for visualization?
Considering the size range of viruses, what implication does this have for visualization?
How does the presence or absence of an envelope affect a virus's interaction with a host cell?
How does the presence or absence of an envelope affect a virus's interaction with a host cell?
A virus is found to contain a segmented RNA genome. What is a likely implication of this genomic organization?
A virus is found to contain a segmented RNA genome. What is a likely implication of this genomic organization?
What aspect of viral structure primarily dictates the specificity of a virus for its host cell?
What aspect of viral structure primarily dictates the specificity of a virus for its host cell?
A researcher is attempting to classify a newly discovered virus. They determine that it contains DNA and has an icosahedral capsid, but lacks an envelope. Which of the following could be the virus?
A researcher is attempting to classify a newly discovered virus. They determine that it contains DNA and has an icosahedral capsid, but lacks an envelope. Which of the following could be the virus?
How does the structure of a bacteriophage contribute to its function?
How does the structure of a bacteriophage contribute to its function?
A virus is found to utilize the host cell's ribosomes for protein synthesis. What does this indicate about the virus?
A virus is found to utilize the host cell's ribosomes for protein synthesis. What does this indicate about the virus?
What is a primary challenge in developing antiviral drugs, given the nature of viruses?
What is a primary challenge in developing antiviral drugs, given the nature of viruses?
How does the lifecycle of a retrovirus differ from that of other RNA viruses?
How does the lifecycle of a retrovirus differ from that of other RNA viruses?
What role do viral enzymes, such as reverse transcriptase, play in the viral replication process?
What role do viral enzymes, such as reverse transcriptase, play in the viral replication process?
Which of the following is most likely to be a characteristic of a virus with a high mutation rate?
Which of the following is most likely to be a characteristic of a virus with a high mutation rate?
How does the concept of 'obligate intracellular parasite' relate to the viral replication strategy?
How does the concept of 'obligate intracellular parasite' relate to the viral replication strategy?
Considering the diversity of viral capsid shapes, what advantage might an icosahedral capsid offer a virus?
Considering the diversity of viral capsid shapes, what advantage might an icosahedral capsid offer a virus?
How does the presence of an envelope affect the transmission of a virus?
How does the presence of an envelope affect the transmission of a virus?
What is the role of the base plate and attached fibers in the infection cycle of a bacteriophage?
What is the role of the base plate and attached fibers in the infection cycle of a bacteriophage?
If a virus has a tropism for specific cells, what determines this specificity?
If a virus has a tropism for specific cells, what determines this specificity?
What is the primary reason viruses cannot replicate through cell division like bacteria?
What is the primary reason viruses cannot replicate through cell division like bacteria?
A newly discovered virus is found to have a small size and a DNA genome. Which of the following virus types might it belong to?
A newly discovered virus is found to have a small size and a DNA genome. Which of the following virus types might it belong to?
How can the study of viral morphology and structure contribute to the development of new antiviral therapies?
How can the study of viral morphology and structure contribute to the development of new antiviral therapies?
Which of the following represents the most accurate depiction of viral classification considering the content?
Which of the following represents the most accurate depiction of viral classification considering the content?
How does the presence or absence of an envelope influence a virus's stability in the environment?
How does the presence or absence of an envelope influence a virus's stability in the environment?
Why do viruses require a host cell to replicate?
Why do viruses require a host cell to replicate?
Flashcards
Viruses
Viruses
Acellular particles containing either DNA or RNA that cannot reproduce on their own and are obligate intracellular parasites.
Bacteriophage (Phage)
Bacteriophage (Phage)
A virus that infects bacteria.
Capsid
Capsid
The protein coat or shell of a virus, encasing its genetic material.
Capsomeres
Capsomeres
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Nucleocapsid
Nucleocapsid
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Spikes
Spikes
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Helical viruses
Helical viruses
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Icosahedral viruses
Icosahedral viruses
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Complex Viruses
Complex Viruses
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Study Notes
- Acellular particles contain either DNA or RNA and are obligate intracellular parasites.
- They do not replicate through cell division.
- Viruses can infect both eukaryotes and prokaryotes.
- Bacteriophages (phages) infect bacteria.
- Viruses are classified based on morphology, capsid shape, nucleic acid type, and viral infection.
Morphology
- Virus size ranges from very small (parvovirus) to large (poxvirus).
- Most viruses are not visible by light microscopy.
- Viruses consist of genetic material carried in a viral coat called a capsid.
- Capsids consist of proteins called capsomeres.
- The association of viral capsid proteins with viral nucleic acid is called a nucleocapsid.
- Some viruses have spikes, which are long projections from the nucleocapsid.
Capsid Shape
- Helical viruses have capsids with rod-shaped capsomeres and can be naked (e.g., tobacco mosaic virus) or enveloped (e.g., flu virus).
- Icosahedral viruses are three-dimensional with many corners, triangular faces, and edges (e.g., Herpesvirus, adenovirus, papovavirus, parvovirus).
- Complex viruses have capsids that are neither purely helical nor completely icosahedral (e.g., bacteriophages).
- Complex viruses have a head (capsid) containing nucleic acid.
- They also have a tail (hollow tube surrounded by a sheath) and a base plate with attached fibers.
Nucleic Acid Type
- Viral nucleic acid can be DNA or RNA, and can be linear or a closed loop.
- Reverse transcribing viruses are an exception.
- Cytomegalovirus (Herpesvirus genus) is a DNA virus that replicates through an RNA intermediate.
- Retroviruses (like HIV) are RNA viruses that replicate through a DNA intermediate.
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