50 Questions
What is the bioscience that studies viral nature and the relationship between viruses and hosts?
Virology
When did the concept of virulation originate, according to the text?
1000 yrs. BC in China
What type of parasites are viruses considered to be?
Obligate intracellular parasites
Which century saw the discovery of bacteriophages, viruses that attack bacteria?
19th century
What types of genome can viruses have based on the text?
Both RNA and DNA simultaneously
Which of the following statements about viruses is true?
Viruses do not move or grow.
What is a characteristic feature of viruses in terms of reproduction?
Viruses rely on host cell processes for replication.
How are viruses different from bacteria in terms of size?
Bacteria are generally smaller than the largest viruses.
Which of the following is essential for viruses to survive in nature?
Infectious nature
What method can be used to measure the sizes of viruses?
Electron microscopy
Who discovered transposons in 1950?
Barbara McClintock
Which hypothesis proposes that viruses may have evolved from complex molecules at the same time as cells first appeared on Earth?
Coevolution hypothesis
What do viroids interact with in host cells for their replication?
Host machinery
Why did the escape hypothesis not explain the complex capsids and other structures on virus particles?
It required host cells for the virus origin
What has led modern virologists to reconsider and re-evaluate classical hypotheses about viruses?
Discovery of ancient viruses
According to the regressive hypothesis, what is the proposed origin of viruses?
Viruses may have once been small cells that parasitized larger cells.
What lends support to the regressive hypothesis of virus origin?
Rickettsia and Chlamydia
Which shape is associated with Filoviridae and Rhabdoviridae viruses?
Bullet-shaped
What is the cellular origin hypothesis of viruses?
Bits of DNA or RNA escaped from larger organisms.
Which type of viruses are suggested to have originated from plasmids or transposons?
Poxviruses
What is the bioscience focused on studying viral nature and the relationship between viruses and hosts?
Virology
When did virology originate?
1000 yrs. BC in China
Which of the following best describes viruses as mentioned in the text?
Inert filterable agents requiring a host cell for energy and protein synthesis
What type of parasites are viruses classified as in microbiology?
Obligate intracellular parasites
Which century witnessed the discovery of bacteriophages, viruses that attack bacteria?
19th century
What is a key characteristic of viruses in terms of their ability to multiply?
Viruses rely on host cell processes for multiplication
Which statement accurately describes the relationship between viruses and unicellular organisms according to the text?
Viruses are known to infect a wide range of unicellular organisms
How do viruses differ from bacteria in terms of growth and reproduction?
Viruses reproduce but do not grow
Why can some bacteria be smaller than the largest viruses according to the text?
Bacteria can pass through filters that hold back viruses
What is a method commonly used for analyzing the sizes of viruses according to the text?
Electron microscopy
What is the alternative name for the vagrancy hypothesis regarding virus origins?
Escape Hypothesis
Why is the regressive hypothesis not considered a valid explanation for the origin of viruses?
It does not explain the complex capsids of viruses
Which hypothesis suggests that viruses evolved concurrently with the appearance of cells on Earth, depending on cellular life for billions of years?
Virus-First Hypothesis
In what way do viroids differ from viruses?
Viroids interact with the host cell for replication
Why does the virus-first hypothesis contradict the definition of viruses according to the text?
It assumes viruses do not require host cells
What does the regressive hypothesis suggest about the origin of viruses?
Viruses originated from small cells that parasitized larger cells and lost unnecessary genes over time.
Why do rickettsia and chlamydia lend support to the regressive hypothesis of virus origin?
Their dependence on parasitism likely led to gene loss similar to viruses.
According to the cellular origin hypothesis, where could the escaped DNA that gave rise to some viruses have come from?
Transposons or plasmids
What is a key difference between bacteria like rickettsia and chlamydia and viruses according to the text?
Bacteria can survive both inside and outside host cells, while viruses can only reproduce inside host cells.
Which statement accurately describes the shape of Filoviridae and Rhabdoviridae viruses?
Bullet-shaped
What is the alternative name for the escape hypothesis in virus origins?
Vagrancy hypothesis
Why did the regressive hypothesis fail to provide a valid explanation for the origin of viruses?
It could not explain why even the smallest cellular parasites do not resemble viruses.
What was a major limitation of the virus-first hypothesis regarding virus origins?
It contradicted the definition of viruses by requiring host cells.
Why did the escape hypothesis not align with the presence of complex capsids and other structures on virus particles?
It overlooked the role of transposons in virus origins.
Which term is used to describe viroids' dependency on host machinery for replication?
Satellites virus
How do viroids differ from viruses in terms of protein coding?
Viroids lack protein-coding genes, unlike viruses.
According to modern virologists, what has led to a re-evaluation of classical hypotheses about viruses?
The recognition of viruses as ancient entities
Why was the regressive hypothesis unable to explain why even the smallest cellular parasites do not resemble viruses?
It did not address the absence of complex capsids on virus particles.
What historical significance do transposons hold in the context of virology?
They are considered a form of ancient viruses.
What sets viroids apart from traditional viral particles in terms of their interaction with host cells?
Viroids utilize host machinery for replication without coding proteins.
Test your knowledge on the shapes and origins of viruses with this quiz. Questions cover topics such as spherical, rod-shaped, brick-shaped, tadpole-shaped, bullet-shaped, and filament viruses. Explore hypotheses including regressive, cellular origin, and coevolution theories.
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