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Questions and Answers
What is the primary component of a virus's structure that surrounds its nucleic acid?
What is the primary component of a virus's structure that surrounds its nucleic acid?
Which characteristic does NOT describe a virus as non-living?
Which characteristic does NOT describe a virus as non-living?
What type of nucleic acid can be found in viruses?
What type of nucleic acid can be found in viruses?
Which scientist concluded that viruses are neither living nor non-living?
Which scientist concluded that viruses are neither living nor non-living?
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What is the term used for viruses that have a lipid or lipoprotein outer coat?
What is the term used for viruses that have a lipid or lipoprotein outer coat?
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Which characteristic is considered a living characteristic of a virus?
Which characteristic is considered a living characteristic of a virus?
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Which statement about the capsid is true?
Which statement about the capsid is true?
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What is the main reason antibiotics are ineffective against viruses?
What is the main reason antibiotics are ineffective against viruses?
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What constitutes the outer coat of some viruses?
What constitutes the outer coat of some viruses?
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What do biochemists prioritize when studying viruses?
What do biochemists prioritize when studying viruses?
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Which of the following viruses are classified as DNA viruses?
Which of the following viruses are classified as DNA viruses?
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What shape is the Tobacco mosaic virus (TMV)?
What shape is the Tobacco mosaic virus (TMV)?
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What characterizes viruses as obligate intracellular parasites?
What characterizes viruses as obligate intracellular parasites?
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Which type of virus predominantly infects animals?
Which type of virus predominantly infects animals?
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Which of the following statements about the structure of viruses is true?
Which of the following statements about the structure of viruses is true?
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Which historical figure is associated with the discovery of the yellow fever virus?
Which historical figure is associated with the discovery of the yellow fever virus?
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Which of the following is NOT classified as a plant virus?
Which of the following is NOT classified as a plant virus?
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What year was the tobacco mosaic virus crystallized, proving its protein and nucleic acid composition?
What year was the tobacco mosaic virus crystallized, proving its protein and nucleic acid composition?
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What is the main nucleic acid type of RNA viruses?
What is the main nucleic acid type of RNA viruses?
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What is the size range of viruses as mentioned?
What is the size range of viruses as mentioned?
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Which virus is known for being a retrovirus?
Which virus is known for being a retrovirus?
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What type of outer membrane does the influenza virus possess?
What type of outer membrane does the influenza virus possess?
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What does the term 'acellular' mean in reference to viruses?
What does the term 'acellular' mean in reference to viruses?
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Which of the following statements about RNA viruses is true?
Which of the following statements about RNA viruses is true?
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Who discovered the silent killer hepatitis C virus?
Who discovered the silent killer hepatitis C virus?
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In terms of shape, which classification correctly describes the Ebola virus?
In terms of shape, which classification correctly describes the Ebola virus?
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What crucial role does the protein coat play in a virus?
What crucial role does the protein coat play in a virus?
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Which of the following is classified as a bacteriophage?
Which of the following is classified as a bacteriophage?
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Study Notes
Shape of Virus
- Viruses can have various shapes: rod-like, ring-shaped, tadpole, cylindrical, oval, or polygonal.
Nature of Virus
- Scientists are uncertain about the nature of viruses.
- Viruses are neither completely living nor non-living.
- In 1962, Stanley and Valens said viruses are intermediate between chemical molecules and living cells.
- In 1974, Salle stated that viruses are substances between living and non-living.
Characteristics of Virus (Non-Living)
- Viruses are acellular and don't contain mitochondria.
- Viruses lack metabolic enzymes.
- They cannot reproduce without a host cell.
- They cannot be filtered by bacteria filters.
- They can be crystallized.
- Outside of a host cell, they are inactive, like chemical particles.
- Viruses don't have physical growth and do not respond to environmental stimulation.
- Chemical compounds like acids, bases, and salts have little to no effect on viruses.
Characteristics of Virus (Living)
- Viruses can reproduce inside host cells.
- Each virus produces a similar virus.
- Structurally, viruses have nucleic acid (either DNA or RNA).
- They are obligate parasites.
- Viruses have a capability to mutate and change.
- Viruses have adaptive capabilities.
- Genetic recombination may occur in viruses.
Structure of Virus
- Viruses have a centrally placed nucleic acid.
- A protein sheath surrounds the nucleic acid, called the capsid.
- The protein molecules in the capsid are arranged in a rod-shaped helix or form a round or polyhedron.
- The outer surface of the capsid sometimes has spikes.
Chemical Structure of Virus
- Viruses usually contain either DNA or RNA, but not both.
- The protein shell protects the nucleic acid.
- Some viruses have an outer coat made of lipid or lipoprotein.
- The outer layer surrounding the capsid is called the envelope.
- The outer coat is vital in some viruses, especially in protecting the nucleic acid during the cold and flu season.
Classification of Virus
- Based on shape: rod-shaped, spherical, cubic, tadpole, or cylindrical.
- Based on nucleic acid: DNA or RNA viruses.
- Based on the outer membrane: enveloped or non-enveloped.
- Based on the host: plant viruses, animal viruses, bacteriophages (viruses that attack bacteria).
- Other types include: cyanophages (attack cyanobacteria), mycophages (attack mycoplasma), phytophagans (attack fungi), and zoophages (attack animals).
- Examples of viruses include: Tobacco mosaic virus (TMV), HIV, influenza, herpes, smallpox, polio, mumps, measles, West Nile virus, and many more.
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Description
Explore the unique and complex world of viruses, their shapes, and the ongoing debate surrounding their living and non-living characteristics. This quiz delves into the defining traits of viruses, highlighting both their acellular nature and capacity for reproduction within host cells. Test your understanding of what makes viruses so intriguing in the realm of microbiology.
