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level: Clinical Virology

Questions and Answers List

level questions: Clinical Virology

Question	Answer
is very relevant today and perhaps even more so as shown by the viral threats that have literally burst into our lives	Virology
outbreak of dengue fever (DF), with over 1.5 million reported cases	Brazil
Ebola outbreak that started in 2014 and lasted until well into 2015	West africa
the spread of Zika virus in November 2015, with a link to microcephaly and subsequent spread to the southern United States	Brazil
the spread of chikungunya virus from the Caribbean countries and territories, first seen in late 2013 and reported in Florida, Puerto Rico, and the U.S. Virgin Islands	United states
Introduction of West Nile virus (WNV) into	North America
Unexpected transfer of monkeypox from	Africa to Midwestern United States
affecting humans and swine throughout the United States and implicated in infections in visitors to county fairs	New variant of influenza A (H3N2)
has killed hundreds of children throughout parts of the Asian continent.	enterovirus 71
At a minimum, viruses contain a viral genome of	RNA or DNA
a protein coat	Capsid
The genome can be double stranded (ds) or single stranded(ss).	True
The genome and its protein coat together are referred to as the	nucleocapsid
entire virus particle is called	Virion
Some viruses also have a phospholipid labile that surrounds the Virion, mask the shape of virion	envelope
typically more susceptible to inactivation by high temperature, extreme pH, and chemicals	Enveloped viruses
are of host origin but contain virus-encoded proteins	Envelopes
The viruses acquire the envelope from the	Host membrane
a geometric shape with 20 triangular sides	helical, icosahedral
There are certain filters just for viruses because they are the most smallest agents that can pass through easily.	Special Filters
Largest virus (250x350nm)	Poxvirus
Smallest human virus (18nm)	Parvovirus
Poliovirus	25nm
Bacterial ribosomes	25nm
Bacteriophage T4	50 nm x 225 nm
Bacteriophage MS2-	24 nm
Tobacco mosaic virus	15 nm x 300 nm
GENERAL CHARACTERISTICS OF VIRUS o Obligate intracellular parasite o Contain either RNA or DNA o 21 families associated with human infections	True
RNA VIRUSES	15
DNA VIRUSES	6
They must be inside a living cell and use those host cell a machinery to	Replicate
Viruses contain either deoxyribonucleic acid (DNA) or RNA but never both. Because they lack ribosomal RNA, viruses are not able to make their own proteins.	True
The viral RNA or DNA is transcribed into messenger (blank) through use of the host cell	mRNA, ribosomes
Viruses cannot generate (blank) and thus depend on host cells to provide these missing components.	adeno sine triphosphate (ATP
o the complete infectious particle o helical, icosahedral (a geometric shape with 20 triangular sides), or complex. o the envelope masks the shape of the virion, so most enveloped viruses are variably shaped or pleomorphic. o inside the virion we have different viral structures (6)	Virion
o constitutes the genetic material or viral genome which can be single or double stranded DNA or RNA o naga dala ng genetic material can be single stranded or double stranded	Nucleic Acid Core
complex morphologic units of the capsid which consist of several identical or different protein molecules. Inside them are nucleic acid core	Capsomere
the capsid together with the enclosed nucleic acid	Nucleocapsid
-lipoprotein envelope that covers the capsid -Acquired from the host cell	Peplos/Viral envelope
viruses with no envelopes	Naked
The envelope is a (blank) in which glycoproteins and matrix proteins are embedded.	phospholipid bilayer
The matrix proteins serve to connect the envelope to the capsid, and the glycoproteins act as (blank) to aid attachment	Spikes
Viruses with enveloped nucleocapsids are more resistant to unfavorable conditions, such as drying and pH changes; they are able to remain moist and are more readily transmitted via respiratory droplets, blood, and other tissues.	True
All negative-sense RNA viruses are	Enveloped
o glycoprotein molecules that bind to host cell during attachment o readily visible under the electron microscope	Spike
Microscope use for viewing viruses is	Electron Microscope
-Originally, viruses were classified by the diseases they caused and their host range. M.D.B - Now, viruses are classified in orders, families, genera, and species based on genome type (RNA or DNA), number of strands in the genome (ds or ss), morphology, and presence or absence of an envelope.	True
o developed by David Baltimore o virus classification system that groups viruses into families, depending on their type of genome (DNA, RNA, single stranded (ss), double-stranded (ds)) and their method of replication	The Baltimore Classification
Group 1 - Double stranded DNA ( DNA +/-) drtso na transcription into mRNA	Adeno, Herpes, Papilloma, Polyoma, Poxviridae
Group II - Single stranded DNA (DNA +) before RNA need pa replication pra magkaroon ng mRNA	Parvoviridae
Group III - Double stranded RNA ( RNA +/-)	Reoviridae
Group IV - Single RNA (RNA +) - mag replicate	Calci, Corona, Flavi, Picorna, Toga
Group V -Single RNA (RNA -) - mag replicat	Arena, Filo, Paramyxo, Rhabdo, Orthomyxo
Group VI - Unique ( RNA +) has reverse transcriptase	Retro
Group VII -Unique ( DNA +/-) has reverse transcriptase	Hepadna
mRNA are	Proteins
o recognize and binds to suitable host cells o glycoprotein spikes binds to host cell CHO receptors determine entry point	Attachment/Absorption
phenomenon called where virus is attracted	Viral Tropism
Absorption is specific for certain cell receptors, and receptor distribution will determine the entry point into the host.	True
Most host cell receptors are	glycoproteins
some of which include the immunoglobulin superfamily molecules	Poliovirus
acetylcholine	rabies virus
sialic acid	influenza virus
CD4	HIV
complement receptor C3d	Epstein Barr virus
o virus enters host cell o using several different mechanism	Penetration
which is specific to naked virion	DIRECT
with cell membrane need to fuse are for envelop viruses	FUSION
envelope viruses will enter the cell using the cytoplasmic vacoule	ENDOCYTOSIS
o virus loses its capsid and exposed its viral genome (DNA or RNA	Uncoating
releases genome in the cytoplasm of the host cell specifically ribosomes	RNA
releases genome in the nucleus	DNA
Once inside the cell, the virus loses its protein coat or the capsid, releasing the genome. This process is called	UNCOATING
The viral genome then directs the host cell to make viral proteins and replicate the viral genome. Depending on the virus, the metabolism of the host cell may be completely stopped (as with polioviruses) or may continue on a restricted scale (as with influenza viruses).	true
as a template for production of mRNA, which codes and directs the synthesis of viral proteins.	viral nucleic acid
protein synthesis occurs in the	host cell cytoplasm
the capsid is synthesized in the	cytoplasm or nucleus.
o after exposure of viral genome either RNA or DNA those will direct into the host cell to make their own viral proteins - necessary to make or replicate its viral genome o production of nucleic acid and protein polymers synthesis of messenger RNA (mRNA) which encodes o early and late viral CHONS	Macromolecular Synthesis
non-structural (enzymes)	Early CHONS
structural components	Late CHONS
maturation of the virus particle o structural CHONS, genome, and enzymes assemble into virions	ASSEMBLY
Final step:	acquisition of envelope
o intact virions are released during: o Cell lysis - naked virions o Budding by cytoplasmic membrane - makakuha ng cytoplasmic membrane na envelope virus if ever - During budding, part of the host cell plasma membrane surrounds the viral capsid and becomes the viral envelope.	RELEASE
is gradually leaked out of the host cell, while some other viruses enzymatically lyse the host cell after replication is completed and are then released.	POLIOVIRUS
Upon release, the virus may spread to local tissues or through the blood, which is known as	VIREMIA
involves viral invasion of cells of the reticuloendothelial system (RES).	PRIMARY VIREMIA
Replication in the RES system can result in a (BLANK) that spreads the virus to distal visceral cells.	SECONDARY VIREMIA
Mode of transmission	Person-person via: o Fecal-oral, sexual contact, trauma or injection of contaminated objects o Tissue transplants (Blood Transfusion), arthropod or animal bites, transplacental
virus infects susceptible cells, frequently in the upper respiratory tract	INSIDE THE HOST
Local infections leads to	VIREMIA
virus that has the ability to stimulate uncontrolled growth of host cells	ONCOGENIC VIRUSES
Approximately how many antiviral drug used	40
 Mostly used in HIV and other viral infections  Categorized according to their mode of action	ANTIVIRAL AGENTS
The virus attaches to specific receptors on the surface of a susceptible cell by means of specialized structures on its surface called	adhesion molecules.
can penetrate the cell membrane directly	NAKED VIRUSES
may enter the cell by fusion with the cell membrane,	ENVELOPED VIRUSES
The new virions are then released by lysis if they are	NAKED VIRUSES
Released by budding if they are	ENVELOPED VIRUSES
best for detecting poxviruses because all other virus particles are too small to be seen.	BRIGHT FIELD MICROSCOPE
Many viruses produce distinctive and characteristic visual changes in infected cells referred to as a	CYTOPATHIC EFFECT
is still the gold standard against which all other methods are compared	VIRAL ISOLATION
cell culture, animal inoculation, and embryonated eggs	VIRAL ISOLATION