Ch. 6

Rank the following from smallest to largest, placing the smallest item at the top.

1. A typical protein 2. A typical Virus 3. A typical bacterial cell 4. A typical eukaryotic cell

What effect would lysozyme have on a eukaryotic cell?

None

In the context of virus replication, fusion with the host cell membrane, injection of nucleic acid, and endocytosis are the three modes of _____.

virus entry into host cells

The image shows the result of mixing bacteriophage T4 with E. coli and adding to a solid medium. The plaques, indicated by the arrow, represent _____.

viruses and lysed bacterial cells

Which of the following viral structures is principally involved in attaching to host cells

Spike proteins

Viruses that have RNA genomes must carry enzymes in their virion to aid in replication once in a host cell.

True

Which two of the following viral activities occurs during "viral entry"?

Uncoating Penetration

The study of viruses is termed

Virology

Which of the following is most likely to function as a viral receptor on a host cell surface?

a protein always present on the cell surface

Which of the following is most likely to function as a viral receptor on a host cell surface?

a protein important in normal cell function

Neuraminidase is an enzyme found in the spikes of influenza virus that ____.

allows mature virions to leave infected cells

Which three of the following are larger than the average virus?

animal cell mitochondrion fungal cell

Fertilized chicken eggs are a good medium to grow _____

animal viruses

The function of viral spike proteins is to ____.

attach to a host cell surface

When performing a viral plaque-forming assay and using the terminology "bacterial lawn", the word "lawn" refers to

bacterial cells virtually side-by-side, covering an agar plate.

Hemagglutinin is a protein found in the spikes of influenza virus that ______.

binds and clumps red blood cells

The specific process of an enveloped virus leaving the cell is called

budding

The protein coat that surrounds the viral nucleic acid is called the

capsid

Which of the following viral structures is composed of just the protein that surrounds the nucleic acid?

capsid

Many RNA viruses must ______ to replicate their genomes.

carry their own enzymes

The best definition of cytopathic effects caused by a viral infection of eukaryotic cells is

changes or abnormalities in infected cells that are distinct from lysis

Virally infected eukaryotic cells often show microscopic or macroscopic abnormalities that are generally called effects

cytopathic

Which two of the following components are not found in viruses?

cytoplasm ribosomes

In contrast to viral genomic DNA, which may be dsDNA, ssDNA, dsRNA, or ssRNA, cellular genomes are always _____

dsDNA

Most bacterial and archaeal viruses have ____ genomes

dsDNA

Most viruses can only be seen using a(n) ______

electron microscope

The second step of the viral life cycle is ___

entry

The outer lipid membranous layer found surrounding some viruses is called the

envelope

Viruses with a lipid membrane are often called ____

enveloped

Viral spike proteins on the influenza virus that facilitate viral attachment to red blood cells are called _____.

hemagglutinin

Which two of the following techniques allow the cultivation of animal viruses?

inoculating fertilized chicken eggs inoculating tissue culture with animal cells

A viral envelope is composed of primarily ____.

lipids

Select the two most common forms of viral release.

lysis budding

Viruses that lack a viral envelope are often called ____

naked

A tumor is a growth or lump of tissue resulting from , ________________which means unregulated abnormal new cell growth and reproduction of a similar cell type.

neoplasia

Viral spike proteins on the influenza virus that aid in the release of mature virions from the host cell are composed of the enzyme _____.

neuraminidase

The simplest viruses consist of nucleic acid surrounded by a protein coat. This composite structure of viral nucleic acid and protein is called a ______.

nucleocapsid

The main difference between virulent phage and temperate phage is that virulent phage _____.

only have a lytic cycle

One method of counting temperate viruses involves mixing the virus and susceptible cells on top of a solid medium. As each virus begins lysing more and more cells, holes can be visualized on top of the medium. The virus-induced holes are specifically called_______________

plaques

The image shows the result of mixing bacteriophage T4 with E. coli and adding to a solid medium. The visible holes are called _____.

plaques

Select the four cellular structures that can be the source of viral envelopes.

plasma membrane Golgi apparatus nuclear membrane endoplasmic reticulum

Infectious agents composed entirely of protein are called _____.

prions

Which two of the following components make up a viral nucleocapsid?

protein coat nucleic acid

Prions are composed of _____.

protein only

Which of the following best defines a plaque-forming unit (PFU)?

A number of virions that generates a single plaque

Give the correct order for a typical viral life cycle beginning with the virus "floating around" in the environment.

Attachment Entry Synthesis Self-assembly Release

Which of the following viral structures comes principally from the host cell?

Envelope

Most viruses can be seen using light microscopes.

False

The cell membrane is the only host cell structure from which enveloped viruses obtain their envelope.

False

The viral-encoded proteins that project from a viral envelope surface are called ____.

spike proteins

Which of the following genomes could be included within a single virus?

ssDNA dsDNA dsRNA ssRNA

Most plant viruses have ____ genomes.

ssRNA

Which of the following describe a bacteriophage that may lyse its host cell, or remain within the cell without lysing it?

temperate

Enveloped viruses gain their envelope from ____

the host cell membrane

Which of the following best describes viral tropism?

the specific cell type that a virus can infect

Some viruses infect specific tissue types but not others. This is called ____.

tropism

The results of virus titration using a plaque-forming assay are normally expressed in PFUs, or plaque-forming

units

Spikes, or peplomers, are _____.

virally-encoded proteins that project from the envelope surface

A complete virus particle is called a(n)

virion

A complete virus particle is referred to as a ____.

virion

Select the three methods used by viruses to gain entry into host cells.

injection of viral nucleic acid into the cell fusion of the viral envelope with host cell membrane endocytosis of the virus into the cell

Which two of the following statements regarding virus structure are correct?

All viruses have a form of nucleic acid, either DNA or RNA. Viruses do not have a cytoplasm.

Most viruses will leave a host cell by bursting the cell, a process called ________________ , or by pushing through the cell membrane while taking some of that membrane with it, a process called _________________

Lysis and budding

Because their host cells typically lack the appropriate enzymes, which type of viruses always encode the enzymes needed to copy their genome?

RNA viruses

Which of the following virus "life" cycle steps is used to describe the lysis of the host cells?

Release

RNA viruses always encode the enzymes needed to replicate their genomes because

host cells typically do not have ways to make RNA from RNA templates.

Budding is best described as

how enveloped viruses acquire their membranes

During T4 bacteriophage release, lysozyme will ____.

hydrolyze the peptidoglycan cell wall