6.1: Viruses

Viruses are usually ultramicroscopic, generally from 20 nm come 900 nm in length. Some big viruses have actually been found. Virions space acellular and consist of a nucleic acid, DNA or RNA, yet not both, surrounded by a protein capsid. Over there may likewise be a phospholipid membrane neighboring the capsid. Viruses room obligate intracellular parasites.

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Multiple Choice

The component(s) that a virus the is/are prolonged from the envelope for attachment is/are the:

A. CapsomeresB. SpikesC. Nucleic acidD. Famous whiskers


Which the the complying with does a virus lack? select all that apply.

A. RibosomesB. Metabolic processesC. Main point acidD. Glycoprotein

A and also B

The envelope the a virus is derived from the host’s

A. Main point acidsB. Membrane structuresC. CytoplasmD. Genome


In naming viruses, the family name ends with ________ and also genus surname ends through _________.

A. −virus; −viridaeB. −viridae; −virusC. −virion; virusD. −virus; virion


What is one more name because that a nonenveloped virus?

A. Enveloped virusB. ProvirusC. Nude virusD. Implicitly virus



True or False: scientists have established viruses that room able to epidemic fungal cells.


Fill in the Blank

A virus that infects a bacter is dubbed a/an ___________________.


A/an __________ virus possesses qualities of both a polyhedral and helical virus.


A virus containing only nucleic acid and a capsid is referred to as a/an ___________________ virus or __________________ virus.

naked or nonenveloped

The ____________ _____________ ~ above the bacteriophage permit for binding come the bacter cell.

tail fibers

Short Answer

Discuss the geometric differences among helical, polyhedral, and facility viruses.

What was the meaning of the word “virus” in the 1880s and why to be it provided to describe the cause of tobacco mosaic disease?

Critical Thinking

Name every labeled component of the illustrated bacteriophage.


In terms of evolution, which do you think arises first? The virus or the host? define your answer.

Do friend think that is feasible to produce a virus in the lab? Imagine that you are a foolish scientist. Define how you would go about creating a new virus.

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Critical Thinking

Label the 5 stages the a bacteriophage epidemic in the figure:


6.4: Viroids, Virusoids, and also Prions

Other acellular agents such as viroids, virusoids, and prions additionally cause diseases. Viroids covers small, naked ssRNAs that reason diseases in plants. Virusoids are ssRNAs the require other helper viruses to create an infection. Prions are proteinaceous contagious particles that reason transmissible spongiform encephalopathies. Prions are extremely resistant come chemicals, heat, and also radiation.