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Questions and Answers
Viruses exhibit all the following except ______.
Viruses exhibit all the following except ______.
- Definite shape
- Ability to infect host cells
- Ultramicroscopic size
- Metabolism (correct)
- Genes
Host cells of viruses include ______.
Host cells of viruses include ______.
- Humans and other animals
- Bacteria
- Protozoa and algae
- Plants and fungi
- All of the choices are correct (correct)
Viruses ______.
Viruses ______.
- Cannot be seen in a light microscope (correct)
- Undergo binary fission
- Are prokaryotic
- Contain 70S ribosomes
Viral capsids are made from subunits called ______.
Viral capsids are made from subunits called ______.
Helical and icosahedral are terms used to describe the shape of a viral ______.
Helical and icosahedral are terms used to describe the shape of a viral ______.
A/an _____ is the protein shell around the nucleic acid core of a virus.
A/an _____ is the protein shell around the nucleic acid core of a virus.
One of the principal viral capsid shapes is a 20-sided figure with 12 evenly spaced corners referred to as a/an _____ capsid.
One of the principal viral capsid shapes is a 20-sided figure with 12 evenly spaced corners referred to as a/an _____ capsid.
A naked virus only has a/an ______.
A naked virus only has a/an ______.
Which of the following is not a typical capsid shape?
Which of the following is not a typical capsid shape?
All of the following pertain to virus envelopes except ______.
All of the following pertain to virus envelopes except ______.
Viral spikes ______.
Viral spikes ______.
The core of every virus particle always contains ______.
The core of every virus particle always contains ______.
Which of the following is not associated with every virus?
Which of the following is not associated with every virus?
Viral nucleic acid types include which of the following?
Viral nucleic acid types include which of the following?
Reverse transcriptase synthesizes ______.
Reverse transcriptase synthesizes ______.
A negative RNA virus must first ______.
A negative RNA virus must first ______.
Viruses with _____-sense RNA contain the correct message for translation, while viruses with _____-sense RNA must first be converted into a correct message.
Viruses with _____-sense RNA contain the correct message for translation, while viruses with _____-sense RNA must first be converted into a correct message.
Classification of viruses into families involves determining all the following characteristics except ______.
Classification of viruses into families involves determining all the following characteristics except ______.
Which of the following represents a virus family name?
Which of the following represents a virus family name?
Which of the following is not a viral order in the classification system?
Which of the following is not a viral order in the classification system?
The correct sequence of events in viral multiplication is ______.
The correct sequence of events in viral multiplication is ______.
Viruses acquire envelopes around their nucleocapsids during ______.
Viruses acquire envelopes around their nucleocapsids during ______.
In general, most DNA viruses multiply in the host cell's _____, while most RNA viruses multiply in the host cell's _____.
In general, most DNA viruses multiply in the host cell's _____, while most RNA viruses multiply in the host cell's _____.
Host range is limited by ______.
Host range is limited by ______.
Oncogenic viruses include all the following except ______.
Oncogenic viruses include all the following except ______.
Which of the following is/are type(s) of cytopathic effects?
Which of the following is/are type(s) of cytopathic effects?
The envelope of enveloped viruses ______.
The envelope of enveloped viruses ______.
Viruses attach to their hosts via ______.
Viruses attach to their hosts via ______.
Viral tissue specificities are called ______.
Viral tissue specificities are called ______.
The process of dissolving the envelope and capsid to release the viral nucleic acid is ______.
The process of dissolving the envelope and capsid to release the viral nucleic acid is ______.
Which of the following occurs during assembly?
Which of the following occurs during assembly?
Mammalian viruses capable of starting tumors are ______.
Mammalian viruses capable of starting tumors are ______.
Persistent viruses that can reactivate periodically are ______.
Persistent viruses that can reactivate periodically are ______.
Which of the following is not a characteristic of a transformed cell?
Which of the following is not a characteristic of a transformed cell?
New, nonenveloped virus release occurs by ______.
New, nonenveloped virus release occurs by ______.
What structures are used by bacteriophages to attach to host cell receptors?
What structures are used by bacteriophages to attach to host cell receptors?
Which of the following is incorrect about prophages?
Which of the following is incorrect about prophages?
T-even phages ______.
T-even phages ______.
The event that occurs in bacteriophage multiplication that does not occur in animal virus replication is ______.
The event that occurs in bacteriophage multiplication that does not occur in animal virus replication is ______.
Viruses that cause infection resulting in alternating periods of activity with symptoms and inactivity without symptoms are called ______.
Viruses that cause infection resulting in alternating periods of activity with symptoms and inactivity without symptoms are called ______.
Uncoating of viral nucleic acid ______.
Uncoating of viral nucleic acid ______.
In transduction, the viral genome ______.
In transduction, the viral genome ______.
Lysogeny refers to ______.
Lysogeny refers to ______.
Viruses that infect bacteria are specifically called ______.
Viruses that infect bacteria are specifically called ______.
During lysogeny, an inactive prophage state occurs when the viral DNA is inserted into the host ______.
During lysogeny, an inactive prophage state occurs when the viral DNA is inserted into the host ______.
What type of phage enters an inactive prophage stage?
What type of phage enters an inactive prophage stage?
The activation of a prophage is called ______.
The activation of a prophage is called ______.
When a bacterium acquires a trait from its temperate phage, it is called ______.
When a bacterium acquires a trait from its temperate phage, it is called ______.
Which of the following will not support viral cultivation?
Which of the following will not support viral cultivation?
Visible, clear, well-defined patches in a monolayer of virus-infected cells in a culture are called ______.
Visible, clear, well-defined patches in a monolayer of virus-infected cells in a culture are called ______.
When a virus enters a host cell, the viral genes redirect the genetic and metabolic activities of the host cell.
When a virus enters a host cell, the viral genes redirect the genetic and metabolic activities of the host cell.
Viruses are used to produce vaccines for prevention of certain viral infections.
Viruses are used to produce vaccines for prevention of certain viral infections.
Viruses are considered ultramicroscopic because they range in size from 2 mm to 450 mm.
Viruses are considered ultramicroscopic because they range in size from 2 mm to 450 mm.
Study Notes
General Characteristics of Viruses
- Viruses lack metabolism, meaning they cannot carry out metabolic processes on their own.
- Viruses possess genetic material (either DNA or RNA) and have a definite shape.
- They are ultramicroscopic, unable to be seen clearly with light microscopes.
Host Cells
- Viruses infect a variety of host cells, including humans, animals, plants, fungi, bacteria, protozoa, and algae.
Virus Structure
- Viral capsids, which protect the genetic material of viruses, are composed of subunits called capsomeres.
- Capsids can have different shapes, with helical and icosahedral being the principal types.
- Naked viruses consist only of a nucleocapsid, which is a protein shell around the nucleic acid.
Virus Envelopes and Spikes
- Viral envelopes are acquired from host cell membranes during the release process.
- Enveloped viruses have spikes that assist in the recognition and attachment to host cells.
Nucleic Acid in Viruses
- The core of every virus contains either DNA or RNA, but not both.
- Viral nucleic acid can be double-stranded DNA, single-stranded DNA, double-stranded RNA, or single-stranded RNA.
Virus Classification
- Viral families are classified based on characteristics such as type of nucleic acid, type of capsid, presence of an envelope, and number of nucleic acid strands.
- Example of a virus family: Herpesviridae, which includes various herpesviruses.
Viral Multiplication Cycle
- The sequence of viral multiplication involves adsorption, penetration, uncoating, synthesis, assembly, and release of new viral particles.
- Most DNA viruses replicate in the host's nucleus, while RNA viruses typically replicate in the cytoplasm.
Host Range and Tropisms
- The range of hosts that a virus can infect is influenced by the type of receptors present on the host cell membrane.
Oncogenic Viruses
- Some viruses can lead to tumor formation and are referred to as oncoviruses (e.g., Papillomavirus, Hepatitis B virus).
- Persistent viruses can reactivate, causing alternating periods of activity and inactivity.
Bacteriophages
- Bacteriophages specifically infect bacteria and may enter a lysogenic phase, where their DNA integrates into the bacterial chromosome.
Cytopathic Effects
- Viruses can cause visible changes in host cells known as cytopathic effects, which include inclusions and multinucleated giant cells.
Prophages and Lysogeny
- Prophages are inactive viral DNA integrated into the bacterial genome during lysogeny.
- Induction refers to the activation of a prophage, resulting in lytic infection.
Viral Cultivation
- Viruses can be cultivated using live lab animals, embryonated bird eggs, primary cell cultures, and continuous cell cultures.
Notable Insights
- The process of uncoating releases viral nucleic acids and occurs after viral penetration.
- Viruses are utilized in vaccine production to prevent certain viral infections.
- Viruses are considered ultramicroscopic due to their extraordinarily small size, typically ranging from 20 nm to 300 nm, contradicting the erroneous size range of 2 mm to 450 mm.
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Description
Test your knowledge of key concepts from Microbiology Chapter 6 with these flashcards. Explore the fascinating world of viruses, including their structure, host cells, and characteristics. Perfect for students looking to reinforce their learning and recall important information.
