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).
What are restriction enzymes?
The bacterial enzymes that recognize foreign DNA and cut it. This is the general defense against viruses.
What is the CRISPR system?
The long-term targeted defense against a specific virus
What is an enveloped virus in animal viruses?
An envelope derived from the host cell
What is a naked virus in animal viruses?
A virus that has no envelope
What are vaccines?
Harmless derivative of a pathogen that stimulates the immune system to mount a strong defense against it. Vaccines have been created for smallpox, measles, polio, hepatitis, mumps, and rubella.
What is a viroid?
Infectious nucleic acid with no protein coat. In short, an infection.
What is a prion?
Infectious self-replicating proteins with no nucleic acid
What are plasmids?
Small circular DNA can be shared between bacteria
What are transposons?
DNA segments that can jump to different sections of the cell’s genome. It does not know where to jump and can cause disruption in the genes.
What are the capsomere in a virus’s capsid?
The protein subunit of a capsid
What are some of the shapes of a capsid from a virus?
Rod-shaped(like a line), polyhedral(like a hexagon), or a complex that has polyhedral head and a rod shaped body(or tail)
What are bacterial viruses?
phage
What is an example of an animal virus?
HIV and AIDS
