INTRODUCTION TO VIROLOGY II Flashcards
This refers to a very small, acellular infectious agents.
Viruses
These are complete virus particles outside of the cell.
Virions
TRUE OR FALSE
Viruses can infect certain organisms only.
False.
“All”
Viruses are referred to as ________ when outside a host cell.
Virions
This is virus-like because it is without a capsid and envelope therefore it is without the protein coat.
Viroid
What is the characteristics of Viroid?
No Capsid
No envelope
Circular DNA
What do Viroid infects?
Only cells
It is a single-stranded RNA called the viroid-like particles that requires help of other viruses so that it can establish an infection.
Virusoids
It is a passenger in virus capsids
Virusoids
What type of RNA do virusoids have? What it is called?
Single stranded RNA
Viroid-like particle
It is believed to consists of a single type of protein molecule without Nucleic acid content.
Prions
The single type of protein molecule of Prions is without?
Nucleic Acid content
Viruses depends on ___________, __________ and _________________ of the host cell for protein and nucleic acid production.
Ribosomes
Enzymes
Metabolites
This is the nucleic acid of the virus and this can be RNA or DNA.
Genome
Single -stranded: _____________
Stranded: ______________
Positive
Negative
This is a coat of protein arranged in one of several possible morphologies, that encloses and protects the genome.
Capsid
How does Capsid participates in infection?
By sharing antigenicity
Viruses can be classified as?
Icosahedral and Helical
This is described as cubical with 20 flat sides.
Icosahedral
This is described as a spiral form of the capsid.
Helical
This is the sub-unit of capsid
Capsomere
This is a lipid containing membrane that surrounds some viral particles.
Envelope
What does the envelope of the virus requires?
Attachment and the budding process of the virus.
What are the purpose of envelope?
Antigenicity
Infectivity
Resistance
What do you call a virus that does not contain an envelope?
Naked virus
What is present in the NUCLEOCAPSIS (NAKED VIRUS)?
DNA or RNA
Structural proteins
Enzymes and nucleic acid binding proteins
What are present in the envelope virus?
Nucleocapsid
Viral specific glycoproteins
Host membrane
It is a glycoprotein that functions as attachment or as an enzyme
Spikes
For DNA, all are double-stranded except for?
Parvoviridae
For RNA, all are single stranded except for?
Reoviridae
Viruses are classified according to type of genetic material, what are these classification?
RNA
DNA
Viruses are classified according to type of CAPSID, what are these classification?
Helical
Polyhedral
This classification is mostly spherical in shape, RNa viruses only
Helical
This classification, can be DNA or RNA viruses. One example of this is Icosahedral
Polyhedral
Enumerate the 6 steps of viral multiplication
- Attachment
- Penetration
- Uncoating
- Biosynthesis
- Assembly
- Release
Attachment is otherwise known as?
Adsorption
During the attachment phase where does the virus attach itself in the human body?
In the specific receptors of the host cell.
Adsorption is _________ and ________.
Generally temperature
Energy dependent
In the penetration process, what does the virus penetrates?
The host cell
It is the engulfment of the host cell by the virus after penetrating it.
Endocytosis
The penetration process is energy-dependent and it can occur through three different mechanisms, what are these?
Translocation of the plasma membrane
Pinocytosis (cell-drinking)
Fusion of the plasma membrane
This phase is where the viral nucleic acid escapes from the capsid and is released inside the host cell for replication.
Uncoating
Biosynthesis is otherwise known as?
Macromolecular synthesis
This phase involves the production of nucleic acids and protein polymers. The host cell replicates the viral nucleic acids .
Biosynthesis
What replicates the RNA that enters the nucleus?
RNA polymerase
This is a phase which the proteins, genomes and enzymes come together to form complete virions.
Assembly
This phase is where the virions are assembled and released from the host cell either by lysis, or budding.
Release
This causes rapid cell death.
Lysis
This is where the viral envelopes are acquired from the host cell membrane without resulting in immediate cell death.
Budding
How does our body defend ourselves from the virus?Ana
Non-specific defenses
Specific defenses
What are the non specific defenses prior to infection?
Anatomical barriers
Viral inhibitors
Phagocytosis
What are the non specific defenses after infection?
fever
Inflammatory processes
Release of interferons
What produces interferons?
Infected cells
What does the release of interferons activates?
RNA endonuclease causing mRNA degradation
Phosphorylation of elF2
This turns off cellular protein synthesis.
Phosphorylation of elF2
This is a eukaryotic initiation factor required for most forms of eukaryotic translation initiation.
elF2
What are the specific host defenses?
Antiviral antibody
This is a natural response of the body to neutralize viruses and prevent adsorption to target cells and cytotoxic T-lymphocytes, which recognize virally-infected cells and destroy them, reducing viral production.
Antiviral antibody
