Chapter 6 : Viruses and other acellular infectious agents Flashcards
The study of viruses is called
Virology
These agents are infectious and unique but simple and are acellular.
Viruses
Which type of viruses only become active when in a living cell and cannot reproduce outside the living host?
Extracellular virus
Which type of viruses command the host cell and hijack transcription/translation to synthesize viral components?
intracellular viruses
Viruses that infect bacteria are called?
bacteriophages
Most viruses effect eukaryotic cell like plants, animals, protists and fungi T o F?
True
What is the nucleocapsid?
Composed of nucleic acid and protein capsid
what does it mean by a enveloped virus?
the virus nucleocapsid is enveloped by lipid membrane
How are the capsids synthesized in viruses?
by the host
function of capsids in viruses?
to protect genetic material and aid in the transfer material
What are the large macromolecules structures that serve as protein coat to viruses?
capsids
What the different types of capsids?
Helical, polyhedral , spherical, and complex
what are the protein subunits that makeup capsids?
protomers
Capsids that are shaped like hallow tubes are called?
helical capsids
Some viruses do not fit into the category of having helical or polyhedral capsids, these are called ?
Complex capsids
What do the large bacteriophages capsids look like?
binal symmetry but icosahedral head but tail is helical
Viral-enveloped viruses contain these structures that extend out for viral attachment are called?
Spike protiens
Viruses can only have single-stranded DNA T o F?
False they can have single and double-stranded DNA or RNA
What are the five steps to viral multiplication
attachment
entry to host
synthesis
assembly
virion release
what is the main idea of tropism in regard to viruses?
Viruses will bind to only specific tissue receptors
How do viruses attach to host cell ?
ligand on virus attached to a receptor on host
What are the three methods used from a virus to enter host cell?
endocytosis
release NA
fusion of viral envelope with host Plasma membrane
What can occur when virus attaches to host cell?
genome or entire capsid may enter the cytoplasm
genome may enter after leaving a capsid attached outside the cell
genome is enclosed
What is the process of entry for viruses via fusion with plasma membrane?
- Spike proteins bind to receptors
- lipid bilayer fuses with envelope of virus
- nucleocapsid is released
What is the process for enveloped virus entering via endocytosis?
- spike proteins bind to the host cell
- triggers endocytosis
- increase in acidity
- nucleocapsid leave to cytoplasm
What is the process for a virus entering via endocytosis that in nonenveloped?
- capsid proteins attach to receptors of the host
- trigger endocytosis
- NA is taken out from endosome into cytosol
For Ds DNA what is the typical synthesis ?
transcription and translation by host
For RNA viruses synthesis typically occurs by?
carrying in or synthesizing the protein to complete synthesis
Early proteins are involved in assembly and late proteins are involved with catalyzing expression and duplication T o F?
early - catalyze and duplication
late - assembly
what are the two virion release mechanisms?
host cell lysis ( non-enveloped) or release by budding ( enveloped)
How many reproductive choices do virulent phages have?
one- multiply and released lytically
How many reproductive choices do temperate phages have ?
two
produce lytically
or remain in host cell with no destruction
what is it called when there is a relationship between a phage and a host?
lysogeny
Form of the virus that remains within the host is called?
prophage
Lysogenic bacteria are ?
infected bacteria
what are cytopathic effects in regards to eukaryotic cells?
degenerative changes or abnormalities in host cell
in plaque essay how are we able to know the presence of virus ?
the virus is diluted and they create plaques and the number correlate to number of viruses
