Biology Virus Unit

In which year was the tobacco mosaic virus first observed using an electron microscope?

1935

An icosahedral virus contains a capsid of ___ equilateral triangles.

20

Which is a current hypothesis about the origin of viruses?

A and B

What does a virus use from the host cell to replicate?

ATP ribosomes enzymes tRNAs

Viruses can have a _____ structure.

All of the above

Which are human diseases caused by a virus?

All of the above

Which of the following does a virus contain?

All of the above

___ kill bacteria but have no effect on viruses.

Antibiotics

The bacteriologist Frederick Twort is credited with the discovery of the ______________ in 1915.

Bacteriophage

The protective coat covering the virus' genetic material is called a _____.

Capsid

Viruses are a strand of genetic material within a protective protein coat called

Capsid

Viruses are essentially a strand of genetic material within a protective protein coating, known as a

Capsid

Which cell part do viruses lack that is shared by all cells?

Cell membrane

The common cold is caused by a corona virus with a ___ shape.

Complex

___ viruses may have extra structures such as protein tails or a complex outer wall.

Complex

Name the virus that infects Pseudomonas bacteria.

Cystovirus

Why do scientists not consider viruses as living things?

Do not have their own metabolism

Which of the following is found in adenovirus?

Double stranded DNA

What allowed scientists to see a virus for the first time?

Electron microscope

Viruses can __________________, which is a function of living cells.

Evolve

All scientists agree that viruses should be considered living things.

False

All viruses are composed of DNA as their genetic material. True or False?

False

All viruses have the same structure.

False

HIV belongs to the adenovirus group.

False

Immunity is not produced by vaccines.

False

It is a fact that viruses are living things.

False

Since the invention of the electron microscope, all viral diseases now have a cure. True or False?

False

The TMV virus is icosahedral virus.

False

The function of the capsid is to make the virus susceptible to the host's immune system.

False

The genetic material of influenza virus is a double helix DNA.

False

The lipids and proteins in a viral envelope are encoded only by viral genetic material. True or False?

False

The rabies virus is a DNA virus.

False

Viruses are much larger than bacteria.

False

Viruses are surrounded by a cell membrane.

False

Viruses belong to the Archaea domain.

False

Viruses do not have nucleic acids or proteins.

False

Viruses originally evolved in the 1900s.

False

Bacteriophages were discovered by:

Frederick Twort

Proteins present in the viral envelope are _____.

Glycoproteins

Viruses of the _________ family have an envelope, are icosahedral in shape, and have double stranded DNA.

Herpesvirus

A virus needs a _____________ cell in order to reproduce.

Host

An enveloped virus provides better protection from the:

Host immune system

How do viruses reproduce?

Infect living hosts, and use host cells to copy their DNA

The capsid shape of cystovirus is _____.

Isocahedral

Is a virus prokaryotic or eukaryotic?

Neither

Are viruses made of cells?

No

Is a virus a living thing?

No

One hypothesis of viruses states that small viruses started as runaway pieces of _____ that originally came from living cells such as bacteria.

Nucleic acid

Complete the sentence using one of the following words: virions, phages, or capsids. Viruses that infect prokaryotes are called

Phages

___ are thought to be the most widely distributed and diverse entities anywhere and everywhere, they are even more numerous than prokaryotes.

Phages

Viruses depend on a host cell to synthesize their ___

Proteins

HIV/AIDS and leukemia are caused by

Retroviruses

To which virus family does the rabies virus belong?

Rhabdovirus

Which is an example of a helical virus?

Tobacco Mosaic Virus

The first virus to be seen was the _____.

Tobacco mosaic virus

A viral capsid may be icosahedral, helical, or complex.

True

A viral envelope has receptor molecules that help bind it to host cells.

True

A virus causes the common cold.

True

Before viruses were identified, scientists knew that particles smaller than bacteria cause disease.

True

HIV is a retrovirus with a genome of single-stranded RNA.

True

Herpes viruses are surrounded by a lipid envelope.

True

Nucleic acids present in a virus may be single or double stranded DNA, or single or double stranded RNA.

True

Scientists knew viruses existed before the invention of the electron microscope. True or False?

True

Scientists were not able to see viruses until the 1930s.

True

Small viruses started as runaway pieces of nucleic acid that originally came from living cells such as bacteria.

True

The electron microscope was the first instrument that allowed scientists to see viruses. True or False?

True

The outer protective protein coat of a virus is called the capsid.

True

The type of host organism is sometimes important in the classification of viruses.

True

Viruses are not composed of cells and do not respire or produce waste.

True

Viruses are not considered to be living.

True

Viruses can be classified on the basis of capsid shape, presence or absence of an envelope, and the type of nucleic acid.

True

Viruses can evolve.

True

Viruses can replicate only by infecting a host cell.

True

Viruses infect and live inside the cells of living organisms.

True

Viruses replicate by infecting a host cell.

True

___ are quite effective at preventing viral infections.

Vaccines

A ___ is a sub-microscopic particle that can infect living cells.

Virus

A ___ is a tiny nonliving particle, containing DNA (or RNA) surrounded by a protein coat, that may cause disease.

Virus

A _________ is a small infectious agent.

Virus

___ are classified according to their envelope, capsid shape, the type of nucleic acid, and the type of disease.

Viruses

___ were first discovered by filtering infected tobacco leaves.

Viruses

Which of the following statements about viruses is true?

Viruses are not considered living things.

What is a reason the virus was first described as a "soluble living germ?" Choose the best answer.

Viruses could pass through filters that bacteria could not and go on to cause infections in experimental organisms

If a virus has an outer viral envelope, it usually indicates that the virus exits the host cell by ________.

exocytosis

A virus is a ____________________ particle that can attack cells.

sub-microscopic