Viruses and Prions Flashcards
What is a host range ?
range of several animal species & tissue cells that virus can infect
- can be broad or limited
What is a capsomere ?
morphological subunits from which virus capsid is built
What is a capsid ?
protein shell or coat that encloses nucleic acid genome
- outer shell that contains the genetic material inside of it
What is the envelope ?
lipid-containing membrane that surrounds some viruses
What is a nucleocapsid ?
capsid together w/enclosed nucleic acid
What is a virion ?
complete infective virus particle
- fully formed virus
What is a incomplete virion ?
virion without nucleic acid
- empty capsid
- doesn’t have genetic material
What is a pseudovirion ?
when the capsid has enclosed genetic material from the host cell instead of the genetic material from the virus
- a mistake
- looks like ordinary virus but it doesn’t replicate
What is a provirus ?
viral DNA that is integrated into host cell chromosome in latent state and must be activated before it is transcribed
- leading to production of progeny virions
- transmissible from parent cell to daughter cell
What is the size of the smallest, largest, and E.Coli viruses ?
- smallest: 20 nm
- largest: 300nm
- E.Coli: 1000nm
What are some general characteristics of viruses ?
- contain either DNA or RNA (never both)
- lack cellular components necessary to generate energy and synthesize proteins
- contain few enzymes
- contain a minimum amount of genetic information
What do most DNA viruses contain ?
contain all their genetic information in a single linear molecule
- can be either single or double stranded
What do most RNA viruses contain ?
can be linear or contain segmented genomes which have several different RNA molecules in their capsid
- each one carrying the same or different genetic information
- can be either single or double stranded
Since viruses have few enzymes what can they do ?
only those involved with entry into cells can replication of their own nucleic acid
- can only multiply inside living cells
How much genetic information do viruses contain ?
contain the bare minimum of their genetic information
- info to make its special protein coat
- info to assure replication of its own chromosome
- info to move the virions in and out of host cell
What determines the shape of the virus ?
the shape of the capsid
- helical or spherical
- each capsid is composed of many identical units (capsomeres)
With the tobacco mosaic virus how can you transmit it ?
if you garden and smoke you can easily transmit the virus to peppers
How do the viruses that have a envelope (lipid membrane) acquire it ?
from cytoplasmic membrane of infected cell
What are some characteristics of viruses with a envelope ?
- structure is similar
- double layer of lipids
- inside the lipid envelope is protein matrix
- spikes project from the envelope and attach the virion to host cell (protein and glycoprotein)
What are some diseases caused by DNA viruses ?
- hepatitis B virus
- gastroenteritis
- HPV
- HSV
- smallpox
What are some diseases caused by RNA viruses ?
- influenza
- zika
- SARS
- ebola
- AIDS
- hantavirus
- rabies
- measles, mumps
- rubella
- pollo, hep A
- rotavirus
- California encephalitis
- dengue fever
In pregnant women, what can zika virus cause ?
can cause microcephaly in their children
What are some S&S of Zika ?
- HA
- pain behind eyes
- fever
- vomiting
- skin rash
- muscle and joint pain
- conjunctivitis
- 1 out of 4 develop symptoms
- symptoms last 1 week
What are the 4 ways of diagnosing viral infections ?
- cell culture
- serological techniques
- direct detection of antigen from specimen
- molecular methods
What is a cell culture diagnosis ?
- living cells
- Ex.) chick embryos
What is a serological technique diagnosis ?
detecting antigen and antibodies
What is a direct detection of antigen from specimen diagnosis ?
polymerase chain reaction (PCR)