Card Set Information
Where do viruses replicate?
They can only replicate inside the host cells
What do viruses use as host cells?
Virus host cells invlude all groups of cellular organisms (bacteria, Archea, Eukaryotes)
What do viruses cause?
What are viruses outside of the host cell?
Outside of the host, viruses exist as inert infectious particles called virions
What is the general form of a virus?
Each type of viruses is essetially a piece of nucleic acid enclosed withi a protein coat- the capsid
What is the protein coat of a virus called?
What are the 4 types of viruses?
Where does a virus get the means to reproduce?
In all cases, the host cells supply the building blocks, the machinery, and the energy required to produce new virus particles
What is the capsid?
A protein coat around the nuclein acid
What is the nucleocapsid part of the virus?
Nucleic acid + protein coat
What are capsomeres?
Protein subunit that make up the capsid
What is the envelope of a virus?
Lipid=containing layer with embedded proteins; in animal viruses, this envelope originate from the cytoplasmic membrane of the host cells
What are envelopes involved with?
They are usually involved in the attachment of the virus ot the next host cell
What does the shapes of virions depend on?
Depends on capsomers
What shape are most mammalian viruses?
What shape are bacteriophage viruses?
Complex virus shape
What is the only type of virus to inject DNA?
Complex virus shapes
What is a helical virus typical of?
Typical of many plant viruses (tobacco mosaic virus)
What is the most common shape of polyhedral viruses?
What is an icosahedron?
Regular polyhedron with 20 triangular faces
What is each face of a polyhedron made of?
Each face is made of one or more capsomere
What does the human papilloma virus look like?
72 clusters of 5 capsomeres (360 capsomeres)
What is a viroid?
Viroids are closed circles of single-stranded RNA comtaining 240-380 nucleotides
What is the replication of viroids dependent on?
Replication is dependent on host machinery, disease is caused by the overtaking of this machinery by the viroid
How does a viroid work?
Hijacks the replication machinery, so the cell repliates it instead of its own DNA
What is circular RNA often mistaken for?
What are prions?
Single infectious proteins
Cannot replicate itself, host does not replicate
Indces other proteins to become prions
How do prions work?
Misfolded protein cause other correctly folded proteins to misfold, and eventually the misfolded protein accuulates and eventually kills the cell