Lecture 3: Virus 02/12/24 Flashcards
What are viruses?
infectious particles of genes packaged in protein coat
What are the structures of viruses?
genome, capsid, and envelope
What is the genome of a virus?
-DNA or RNA
-single or double stranded
-linear or circular
-single or multiple pieces
What is the capsid of a virus?
A protein shell that encloses the viral genome
What is the envelope of a virus?
A membrane derived from host cell membranes found in some animal viruses
What is in the envelope of a virus?
Phospholipids and membrane proteins from the host cell. Also, contains glycoproteins and enzymes of viral origins. An example is influenza.
What is the viral replicative cycles?
The virus form of reproduction since they are not “living”
What is the obligate intracellular parasite?
A parasite that can only replicate inside the host cell since they cannot make their own proteins or nucleic acids.
What is host range?
The limited number of species a virus can infect
What is host specificity?
The evolutionary recognition of receptor proteins on host cell, similar to the lock and key mechanism. Examples include the West Nile Virus that only affects specific animals like horses or humans. Another example is measles that only affects humans.
What is the lytic cycle in bacterial viruses?
The replicative cycle that ends in the death of the host cell
What is the virulent?
A virus that replicates only by lytic cycle. An example is e coli that attaches to bacteria and binds to receptors through its tail. Then it enters and injects the nucleic acid material and leaves protein coat outside. They then cut up the host cell DNA and take over the cell to make more virus particles. They release and burst the cells. An example of this infleunza or the adenovirus(cold)
What is lysogenic cycle in bacterial viruses?
The replicative cycle that incorporates into the host genome.
What is temperate in the lysogenic cycle?
A virus that uses lysogenic replicative cycle. Similar to the other cycle, it attaches and enters but instead integrates the viral DNA to the host genome. So, the viral DNA is carried in the cells and multiplies within the daughter type. An example of this is pathogenic e coli.
What is genetic diversity?
Where not all cells in a population have exact same surface receptors proteins to match virus(viral immunity).