37 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 years BC
Which type of parasites are viruses according to the text?
Intracellular parasites
What is the primary genetic material found in viruses based on the text?
Both RNA and DNA simultaneously
Who is credited with discovering viruses in the year 1892 according to the text?
Dmitri Ivanovsky
What is the primary use of bacteriophages mentioned in the text?
Studying molecular biology
What is a characteristic of viruses according to the text?
Viruses reproduce
Which statement about viruses is true based on the text?
Viruses vary greatly in structure and genome organization
What is a method used to measure the sizes of viruses as mentioned in the text?
X-ray crystallography
What is a key requirement for viruses to endure in nature?
Being able to produce host cell components
Which of the following is NOT a characteristic of viruses according to the text?
Viruses respire actively
What is a feature of the size of small viruses as per the text?
$<30$ capsomeres
Who discovered transposons in 1950?
Barbara McClintock
What is another name for the virus-first hypothesis?
Escape hypothesis
What do viroids interact with in host cells for their replication?
Host machinery
Why did the regressive hypothesis fail to explain the nature of viruses?
It did not explain complex capsids on virus particles
What led modern virologists to reconsider classical hypotheses about virus origins?
Recognition of ancient virus origins
What do viroids not code for?
Proteins
What is the origin hypothesis that suggests viruses may have once been small cells parasitizing larger cells?
Regressive hypothesis
Which virus family is associated with brick-shaped viruses?
Poxviridae
What is the proposed origin of some viruses according to the cellular origin hypothesis?
Escape from larger organism genes
Which virus shape is described as tadpole-shaped?
Bullet-shaped
Which living cells are cited as lending support to the regressive hypothesis of virus origin due to their dependence on parasitism?
Bacteria
According to the regressive hypothesis, what led to the loss of genes in viruses over time?
Reduction in gene requirements for parasitism
Who is credited with the discovery of transposons in 1950?
Barbara McClintock
What is the other name for the virus-first hypothesis mentioned in the text?
Vagrancy hypothesis
Why did the regressive hypothesis fail to explain the nature of viruses according to the text?
It couldn't account for the complex capsids on virus particles.
What do viroids interact with in host cells for their replication?
Ribosomes
How are viroids different from viruses according to the text?
Viroids do not code for proteins.
What is a characteristic of the size of small viruses as per the text?
They are smaller than bacteriophages.
According to the cellular origin hypothesis, why would viruses have been dependent on cellular life for billions of years?
To use cellular machinery for replication.
Why did the escape hypothesis not explain the complex capsids and other structures on virus particles?
'It assumed viruses evolved independently from cells.'
What hypothesis, also known as the virus-first hypothesis, suggests that viruses may have evolved from complex molecules at the same time as cells first appeared on Earth?
Coevolution hypothesis
Why did the escape hypothesis fail to explain the complex capsids and other structures found on virus particles?
It contradicted the definition of viruses that require host cells.
According to modern virologists, what has led to the reconsideration of classical hypotheses regarding virus origins?
Recognition of viruses as ancient.
What did the regressive hypothesis fail to explain about even the smallest cellular parasites?
Their lack of resemblance to viruses.
Why do viroids interact with host cells and use host machinery for replication despite not coding for proteins?
To ensure their own replication and survival.
Explore the different shapes and origins of viruses in microbiology and medical virology. Learn about spherical, rod-shaped, brick-shaped, tadpole-shaped, bullet-shaped, and filament viruses, as well as regressive, cellular origin, and coevolution hypotheses regarding the origin of viruses.
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