Podcast
Questions and Answers
What is necessary for viruses to reproduce?
What is necessary for viruses to reproduce?
- In a laboratory setting
- Within a virus particle
- In presence of light
- Inside a living cell (correct)
Which of the following characteristics is NOT true about viruses?
Which of the following characteristics is NOT true about viruses?
- They can mutate.
- They have metabolism. (correct)
- They contain DNA or RNA.
- They are non-cellular.
What is true about the reproduction of viruses compared to cells?
What is true about the reproduction of viruses compared to cells?
- Cells reproduce only within a host cell.
- Cells can reproduce independently without a host. (correct)
- Viruses reproduce either sexually or asexually.
- Viruses can reproduce independently without a host.
What process do viruses use to make host cells produce viral components?
What process do viruses use to make host cells produce viral components?
What happens to the host cell at the end of the viral reproductive cycle?
What happens to the host cell at the end of the viral reproductive cycle?
Which statement accurately describes the role of vaccines in relation to viral infections?
Which statement accurately describes the role of vaccines in relation to viral infections?
What is the primary reason that antibiotics are ineffective against viral infections?
What is the primary reason that antibiotics are ineffective against viral infections?
Which statement about viral genetic material is true?
Which statement about viral genetic material is true?
Which of the following diseases is NOT typically caused by a virus?
Which of the following diseases is NOT typically caused by a virus?
What is a characteristic that distinguishes viruses from living organisms?
What is a characteristic that distinguishes viruses from living organisms?
What makes viral diseases particularly challenging to treat?
What makes viral diseases particularly challenging to treat?
What term describes the viral components produced by the host cell?
What term describes the viral components produced by the host cell?
Which of the following best describes the entry of a viral infection into a host cell?
Which of the following best describes the entry of a viral infection into a host cell?
What does the word 'virus' derive from in Latin?
What does the word 'virus' derive from in Latin?
Which of the following describes the state of a virus when it is outside of a living cell?
Which of the following describes the state of a virus when it is outside of a living cell?
What must a virus's capsid shape do to successfully infect a host cell?
What must a virus's capsid shape do to successfully infect a host cell?
Which statement is true about the virus's structure?
Which statement is true about the virus's structure?
How do viruses demonstrate specificity towards the cells they infect?
How do viruses demonstrate specificity towards the cells they infect?
What is implied by the statement that viruses are non-cellular?
What is implied by the statement that viruses are non-cellular?
What type of virus can the Papaya Ringspot Virus infect?
What type of virus can the Papaya Ringspot Virus infect?
What is the role of the base plate in a virus?
What is the role of the base plate in a virus?
What happens during a lytic infection?
What happens during a lytic infection?
Which of the following characteristics distinguishes the lysogenic cycle from the lytic cycle?
Which of the following characteristics distinguishes the lysogenic cycle from the lytic cycle?
What is the role of tail fibers in the lytic cycle?
What is the role of tail fibers in the lytic cycle?
What primary event occurs after the viral DNA is injected into the host cell during the lytic cycle?
What primary event occurs after the viral DNA is injected into the host cell during the lytic cycle?
What is a defining feature of lysogenic viruses?
What is a defining feature of lysogenic viruses?
Which of the following processes occurs during the lytic cycle?
Which of the following processes occurs during the lytic cycle?
In the lytic cycle, what typically happens to the host cell after producing viral particles?
In the lytic cycle, what typically happens to the host cell after producing viral particles?
When a lysogenic virus integrates its DNA into the host genome, its DNA is considered to be:
When a lysogenic virus integrates its DNA into the host genome, its DNA is considered to be:
What characterizes the lysogenic cycle in relation to the prophage?
What characterizes the lysogenic cycle in relation to the prophage?
When does the transition from the lysogenic cycle to the lytic cycle typically occur?
When does the transition from the lysogenic cycle to the lytic cycle typically occur?
Which statement about bacterial cell division in the context of the lysogenic cycle is correct?
Which statement about bacterial cell division in the context of the lysogenic cycle is correct?
What is the primary outcome of the lytic cycle?
What is the primary outcome of the lytic cycle?
In what way does the prophage differ from an active viral infection?
In what way does the prophage differ from an active viral infection?
What happens during the bursting of the host cell in the lytic cycle?
What happens during the bursting of the host cell in the lytic cycle?
Which of the following conditions may trigger the transition from the lysogenic cycle to the lytic cycle?
Which of the following conditions may trigger the transition from the lysogenic cycle to the lytic cycle?
Which feature is NOT a determinant in the propagation of the lysogenic and lytic cycles?
Which feature is NOT a determinant in the propagation of the lysogenic and lytic cycles?
Flashcards
What is a virus?
What is a virus?
A non-living, infectious particle that cannot reproduce on its own and requires a host to survive.
Why are viruses considered parasites?
Why are viruses considered parasites?
Viruses are considered parasites because they live in or on other living organisms, causing harm to their host.
What is a host?
What is a host?
The living organism that a virus infects and relies on for reproduction.
What is a capsid?
What is a capsid?
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How does the capsid contribute to viral specificity?
How does the capsid contribute to viral specificity?
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Why are viruses highly specific to their hosts?
Why are viruses highly specific to their hosts?
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What are the limitations of viruses?
What are the limitations of viruses?
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How does tissue specificity affect viral infections?
How does tissue specificity affect viral infections?
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What is a key characteristic of viruses that distinguishes them from living organisms?
What is a key characteristic of viruses that distinguishes them from living organisms?
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How do viruses reproduce?
How do viruses reproduce?
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What does a virus do to a host cell once it has entered it?
What does a virus do to a host cell once it has entered it?
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What triggers the start of a viral infection?
What triggers the start of a viral infection?
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After viral genetic material enters the host cell, what happens next?
After viral genetic material enters the host cell, what happens next?
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How are new viruses created within the host cell?
How are new viruses created within the host cell?
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What is the final outcome of the viral reproductive cycle?
What is the final outcome of the viral reproductive cycle?
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What is one characteristic that viruses share with living organisms?
What is one characteristic that viruses share with living organisms?
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What is the lytic cycle?
What is the lytic cycle?
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What is the lysogenic cycle?
What is the lysogenic cycle?
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What is the function of tail fibers in bacteriophages?
What is the function of tail fibers in bacteriophages?
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What happens during the entry phase of the lytic cycle?
What happens during the entry phase of the lytic cycle?
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What happens during the synthesis phase of the lytic cycle?
What happens during the synthesis phase of the lytic cycle?
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What happens during the assembly phase of the lytic cycle?
What happens during the assembly phase of the lytic cycle?
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What happens during the release phase of the lytic cycle?
What happens during the release phase of the lytic cycle?
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How does the viral DNA replicate in the lysogenic cycle?
How does the viral DNA replicate in the lysogenic cycle?
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Why don't antibiotics work against viruses?
Why don't antibiotics work against viruses?
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How do vaccines work?
How do vaccines work?
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Why can we get the flu every year?
Why can we get the flu every year?
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How are viral diseases spread?
How are viral diseases spread?
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What are some common viral diseases?
What are some common viral diseases?
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What is a prophage?
What is a prophage?
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What are the two main life cycles of bacteriophages?
What are the two main life cycles of bacteriophages?
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What can trigger the switch from the lysogenic cycle to the lytic cycle?
What can trigger the switch from the lysogenic cycle to the lytic cycle?
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What stays inactive within the host cell during the lysogenic cycle?
What stays inactive within the host cell during the lysogenic cycle?
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What happens when the lysogenic cycle switches to the lytic cycle?
What happens when the lysogenic cycle switches to the lytic cycle?
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What is the outcome of the lytic cycle?
What is the outcome of the lytic cycle?
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Study Notes
Virus Basics
- Viruses are infectious particles, but they are nonliving.
- The word "virus" comes from the Latin word meaning "poison."
- Viruses are parasites, requiring a host to survive.
- A host is the living organism a parasite lives on or in.
- Viruses are extremely small, needing an electron microscope to be seen.
Viral Characteristics
- Viruses are active only inside living cells.
- Outside a host cell, viral activity ceases, but the virus retains its ability to infect.
- Viruses can be crystallized & stored for long periods but remain infective.
- Viruses vary widely in size and structure.
- All viruses enter a living cell and use the cell's mechanism to create more viruses.
- Viral structure includes a capsid (a protein coat), base plate, tail fibers, sheath, and DNA or RNA.
Viral Classification
- Viruses are non-cellular.
- Viruses have two main components: DNA or RNA surrounded by a protein coat, called the capsid.
- The capsid has a specific shape matching receptors on a host cell so the virus can enter.
- When a virus attaches to these receptors, the cell is tricked into allowing the virus inside.
- Viruses are highly specific to the cells they infect. Plant viruses only infect plant cells, animal viruses only infect animal cells, and similar viral types for certain eukaryotes/bacteria.
Viral Reproduction
- Viruses reproduce only inside living cells.
- Viruses hijack the host cell instructing it to produce viral components rather than cellular components (e.g. proteins of viral capsids etc).
- The viral genome takes over the host cell, directing the cell to create new viruses.
- The host cell produces copies of the viral DNA and creates capsid proteins.
- The host cell assembles these components into complete new viruses.
- The reproductive cycle concludes with the release of numerous new viruses from the host cell, causing the host cell to usually die.
- Viral reproduction can be either lytic (immediate destruction of host cell causing cell death) or lysogenic (viral DNA integrates itself into host cell DNA & replicates along with host cell DNA – may stay dormant for a time).
Viral Diseases
- There are few cures for viral infections.
- Antibiotics are effective against bacteria, not viruses.
- Some new antiviral drugs have been developed but primarily slow the viral effects rather than curing.
- The control of viral diseases relies on vaccines.
- Vaccines contain a harmless variation of the pathogen (harmless form of the virus), which triggers an immune response whereby the immune system learns to recognize the pathogen.
- Subsequent exposure to the real virus allows the immune system to respond quickly and effectively.
- Examples of viral diseases include flu, colds, chickenpox, AIDS, hepatitis, and West Nile.
Viruses vs. Cells
- Viruses lack cellular structure, whereas cells have a membrane, cytoplasm, nucleus, and organelles.
- Viruses reproduce only within a host cell whereas cells can reproduce on their own (or in conjunction with other cells for certain processes).
- Viruses use DNA or RNA for their genetic material, while cells use DNA.
- Viruses do not use energy or obtain nutrients. Cells perform these functions.
- Cells respond to their environments and can grow & develop, while viruses cannot.
- Viruses evolve, as cells do.
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Description
Test your knowledge on the characteristics of viruses and their reproductive processes with this quiz. Explore how viruses differ from living organisms, the role of vaccines, and the challenges in treating viral diseases. Assess your understanding of viral infections and their impact on host cells.
