viruses and prions Flashcards
in what way are viruses metabolically inert?
they do not posses ribosomes
what is the name for a complete virus particle?
virion
what does a viral envelope consist of?
lipid membrane
do all viruses contain an envelope?
no
what is a viral capsid?
protein shell protecting nucleic acid
what are the protein units that make up a capsid called?
capsomer
what is the viral genome?
RNA or DNA
how may viruses be transmitted?
inhalation via respiratory tract, ingestion via GIT, inoculation, congenitally, sexually
give an example of a virus transmitted via inhalation
influenza
give an example of a virus transmitted via ingestion
Hep A
give an example of a virus transmitted via inoculation
Hep B
give an example of a virus transmitted congenitally
Herpes
give an example of a virus transmitted sexually
HIV
give an example of a virus affecting the nervous system
rabies
give an example of a virus affecting the respiratory tract
influenza
give an example of a virus affecting skin or mucous membranes
herpes
give an example of a virus affecting the eyes
ocular herpes
give an example of a virus affecting the liver
hepatitis
give an example of a virus affecting salivary glands
HIV-SGD
give an example of a virus affecting the GIT
norovirus
what effects may a virus have on the host cell?
cytopathic effect - cell death
transformation - to cancerous cell
latent infection - no effect on cell function
name the steps of viral replication
attachment, penetration, uncaring, synthesis of viral components, assembly, release
what occurs during the attachment phase of viral replication?
Virus attaches to host cell membrane and injects DNA/RNA into host - initiating infection
what occurs during the penetration phase of viral replication?
cell membrane enfolds around virus, enclosing it into a vacuole. protecting the cell from antibodies
what occurs during the uncoating phase of viral replication?
cell lysozyme strip off virus protein coat, releasing viral genome
what occurs during the synthesis of viral components phase of viral replication?
virus takes advantage of cell structures to replicate itself
what occurs during the assembly phase of viral replication?
newly synthesised genome and proteins are assembled to form new virus particles
what occurs during the release phase of viral replication?
viruses are released from host cell by sudden rupture or gradual extrusion through host membrane
what virus causes herpes
herpes simplex virus
what does oral herpes cause
sore throat and small blisters called cold sores
what is the abbreviated name for oral-facial herpes simplex virus?
HSV-1
how does the herpes virus reoccur in the form of a coldsore?
once initial infection has receded, the virus lies dormant in the trigeminal nerve
name the 3 types of influenza
a,b and c
name the 2 glycoproteins on the surface of the influenza virus
haemagglutinin (HA), neuroaminidase
what is the differences between antigenic drift and antigenic shift in influenza viruses?
drift - minor changes, epidemics, a,b and c
shift - major changes, pandemic, only a
how is herpes tested?
antibody gig test, DNA detection
what causes CJD?
abnormal infectious proteins called prions
do prions contain DNA or RNA?
no
why is CJD untreatable?
prions cannot be destroyed by heat or radiation and there is no medication or treatment for them
