Micro 5,11
Since 2000, the number of orders of viruses recognized by the International Committee on the Taxonomy of Viruses has risen from _______ to ________.
1:8
What percentage of human DNA is thought to consist of viral DNA sequences?
8
what is the primary reason why it is more difficult to design antiviral drugs than antibacterial drugs
Antiviral drugs often must target host cell functions which results in side effects in the host.
The principal government agency responsible for tracking infectious diseases in the United States is the _____.
Centers for Disease Control and Prevention
Reverse transcriptase synthesizes
DNA from RNA
Viruses attach to their hosts via
Host glycoproteins
One of the principal capsid shapes is a 20-sided figure with 12 evenly spaced corners referred to as a(n) _____ capsid.
Icosahedral
Who created the rabies vaccine using a filter?
Pasteur
infectious agents that are noncellular
Prions, Satellite Viruses, Viroids
what is the role of viral surface proteins or spikes
Provide means of attachment to host cell surface
What is not a typical capsid shape?
Tetrahedral
what is true regarding reportable diseases?
There are over 75 reportable diseases caused by a large variety of microorganisms.
Why do antiviral medications often have side effects?
Viruses are intracellular pathogens, and therefore, there is often host cell damage with antiviral treatments
A _______ is the presence of small numbers of bacteria in the blood.
bacteremia
Of all infectious agents, which group has the most variety of drugs designed to treat infections?
bacteria
Animals that participate in the life cycles of pathogens and transmit pathogens from host to host are ____
biological vectors
The suffix -emia means _______.
blood
Helical and icosahedral are terms used to describe the shapes of a virus _____.
capsid
Opportunistic pathogens
cause disease in compromised individuals
what characteristics are exhibited by endtoxins
composed of lipopolysaccharide heat stable fever inducing
What is not a characteristic of a transformed cell?
decreased growth rate
The movement of molecules from an area of high concentration to an area of lower concentration is called _____.
diffusion
An infectious agent already existing on or in the body is called _____.
endogenous
what is not associated with every virus
envelope
what describes a virus that has a membranous outer covering over its capsid, partially derived from a host cell.
enveloped virus
Microbial hyaluronidase, coagulase, and streptokinase are examples of
exoenzymes
A teacher walking through her first-grade classroom pauses to pick up a used tissue that had ended up on the floor instead of in the waste basket. Unfortunately, after discarding the tissue, she doesn't immediately wash her hands, and acquires a strain of rhinovirus. Several days later she begins to experience symptoms of a cold. Based upon this scenario, please select the mode of disease transmission demonstrated here.
formite
An inanimate object that harbors and transmits a pathogen is a _____.
formite
Viruses attach to their hosts via ________.
host glycoproteins
The number of new cases of a disease in a population over a specific period of time compared with the healthy population is the _____.
incidence rate
An endotoxin is
indicative of gram-negative organisms
The activation of a prophage is called _____.
induction
patterns of direct transmission of infectious disease are
kissing and touching droplet
Viruses that cause infection resulting in alternating periods of activity with symptoms and inactivity without symptoms are called _____.
latent
example of an endotoxin
lipopolysaccharide
New, nonenveloped virus release occurs by _____.
lysis
When phage nucleic acid is incorporated into the nucleic acid of its host cell and is replicated when the host DNA is replicated, this is considered part of which cycle?
lysogenic cycle
This occurs when a bacteriophage infects bacteria and the bacteria are ruptured or lysed
lytic infection
Microorganisms require large quantities of _____ for use in cell structure and metabolism.
macronutrients
Viruses lack the ability to
metabolize
The number of persons afflicted with an infectious disease is the _______ rate.
morbidity
Resident biota are found in/on the ________.
mouth skin large intestine nasal passages
A negative-sense RNA virus ________.
must synthesize a positive RNA copy of its genome
Viruses are usually _________ in size, and their structure is best viewed through the use of ________ microscopy.
nanometers; electron
A naked virus only has a(n)
nucleocapsid
In general, most DNA viruses multiply in the host cell's _______, while most RNA viruses multiply in the host cell's _______.
nucleus, cytoplasm
an organism that lacks superoxide dismutase and catalase enzyme
obligate anaerobe
Uncoating of viral nucleic acid ________.
occurs before replication involves enzymatic destruction of the capsid releases viral nucleic acid into the cell does not occur in bacteriophage multiplication
Mammalian viruses capable of starting tumors are
oncoviruses
Most of the dry weight of a microbial cell is from
organic compounds
diffusion of water through a selectively permeable membrane
osmosis
Clear patches in cell cultures that indicate sites of virus infection are called ________.
plaques
The percentage of the population with a particular disease at any point in time is the _______ of disease, whereas the number of new cases over a given time period is the _______ of disease.
prevalence; incidence
Infectious protein particles are called
prions
Exotoxins are
proteins
viral spikes
protrude from the envelope.
what cannot find a location in or on body tissues suitable for growth
psychrophiles
The host cells that viruses can infect are determined by the ____________.
receptors of the host cells
All protein synthesis takes places in the hosts
ribosomes
organisms that feed on dead organisms for nutrients
saprobes
what is not a factor that weakens host defenses against infections?
strong healthy body
The toxic superoxide ion is converted to harmless oxygen by two enzymes
superoxide dismutase and catalase
What structures are used by bacteriophages to attach to host cell receptors?
tail fibers
What type of phage enters an inactive prophage stage?
temperate
A virus that undergoes lysogeny is a/an _________.
temperate phage
Pathogenic microbes that cause disease in healthy people are called _____
true pathogens
Host range is limited by
type of host cell receptors on cell membrane
The term autotroph refers to an organism that
uses CO2 for its carbon source
Rather than developing more antiviral medications, what is a more common focus for researchers when it comes to viral disease?
vaccine development
An animal, such as an arthropod, that transmits a pathogen from one host to another is a _____.
vector
Animals that participate in the life cycles of pathogens and transmit pathogens from host to host are ____
vector
Tooth decay develops when human saliva and proteins aggregate on the tooth and provide a hospitable surface for a range of microbial species to develop into a biofilm. These organisms ferment carbohydrates and the acid byproducts erode the enamel, forming caries. Tooth decay is therefore considered to be _____.
a polymicrobial infection
Creutzfeldt-Jacob disease is ________.
a spongiform encephalopathy of humans