Overview of Viruses

Multiply by taking control of host cell's genetic material and regulating the synthesis and assembly of new viruses

Obliget intracellular parasites of bacteria, protists, fungi, plants, and animals (correct)

Not cellular in nature; structure is very compact and economical (correct)

Lack machinery for synthesizing proteins

Inactive macromolecules outside the host cell and active only inside host cells

Molecules on virus surface impart high specificity for attachment to host cell

Nucleic acid can be double-stranded DNA, single-stranded DNA, single-stranded RNA, or double-stranded RNA

Basic structure consists of protein shell (capsid) surrounding nucleic acid core

Nucleic acid of the viral genome is either DNA or RNA but not both

Lack enzymes for most metabolic processes

Do not independently fulfill the characteristics of life

Ultramicroscopic size, ranging from 20 nm up to 750 nm in diameter (correct)

The term 'ultramicroscopic' means that an electron microscope is necessary to detect minute or to examine their fine structure.

More than 2,000 bacterial viruses could fit into an average bacterial cell.

<p>More than 50 million human cell viruses could be accommodated by an average human cell.</p> Signup and view all the answers

<p>Small viruses range in size from the small parvoviruses (around 20 nm in diameter) to megaviruses and pithoviruses (around 500 nm in width).</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>A simple protein shell (capsid) surrounding a nucleic acid core</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>Molecules on virus surface impart high specificity for attachment to the host cell.</p> Signup and view all the answers

<p>Viruses multiply by taking control of the host cell's genetic material and regulating the synthesis and assembly of new viruses.</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>The virome is the collection of viruses that exist in the human body.</p> Signup and view all the answers

<p>Viruses are not living things but exist independently from the host cell. They are not living things but exist closer to large, infectious molecules. In any event, many viruses are agents of disease and must be dealt with through control, therapy, and prevention.</p> Signup and view all the answers

<p>Viruses are obligate intracellular parasites because they can only replicate inside living cells.</p> Signup and view all the answers

<p>Viruses</p> Signup and view all the answers

<p>Giant viruses, pandoraviruses, megaviruses, and pithoviruses are 20 to 50 times larger than an average virus and even larger than small bacteria such as rickettsias.</p> Signup and view all the answers

<p>Giant viruses, pandoraviruses, megaviruses, and pithoviruses were mistakenly viewed as small bacteria and ignored by virus hunters.</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>Giant viruses, pandoraviruses, megaviruses, and pithoviruses are often discovered as parasites inside the cells of amoebas living in aquatic habitats.</p> Signup and view all the answers

<p>These viruses have a typical viral cycle, multiplying in the host cytoplasm. They lack cellular structure and ribosomes, metabolic enzymes, and fission-style division.</p> Signup and view all the answers

<p>Giant viruses raise questions about where these unusual viruses fit on the 'tree of life,' if anywhere at all.</p> Signup and view all the answers