Vriuses Flashcards
What are viruses
they are arrangemetns of gentic material and protein that invade other living cells and take over their biochemistry to make more viruses `
What is the protein coat (capsid) made up
repeating protein units known as capsomers arranged in diffrent ways
What is + for the presences of the lipid envlope
makes it easier for the viruses to pass from cell to cell
What makes the lipid envlope vunerable
substances such as ether which dissolve the lipid membrane
What is the benefit for using repeating units
It reduces the genetic materiel needed to code fro coat production
What are VAPS (Virus attachment particles)
specfic proteins that target proteins in the host cell surface membrane
How can viruses be classifed
genome and there mode of replication
Viral gentic materail can be what
DNA or RNA and the nucleic acid is sometimes double stranded and sometimes single
What is a DNA virus
contains DNA which can directly act as template for mRNA transcription and DNA replication
What is a RNA viruses
Contain RNA and make new RNA from it : no DNA is made
What is a retroviruses
type of RNA that directs the synthesis of the enzyme reverse trnascriptase This makes the DNA versions of the RNA genome
The DNA is incoprated into the host cell and used to make more viral proteins and RNA genome
What is reverse transcriptase
an enzyme synthesised in the life cycle of a retrovirus that makes DNA molecules corresponding to the vrial RNA genome
Explain latency
Talk about it
What is lysogney
the period when a virus is part of the reproducing host cell but does not affect it adversley
What does latent mean
the state of non viruent virus within the host cell
How are viruses classified
according to their strucuture and type of nucleic acid
Features of an RNA and retrovirsues
Single strand of RNA
Reverse transcriptase enzyme produces cDNA from RNA template
Double stranded viral DNA intergrates into a host cells genome
Describe the lytic pathway 1/2
`Virulent viruses inject nucleic acid into the host cells cytoplasm. Viral genetic info replicates immediately, independent of the host cell
Describe the lytic pathway 2/2
many virons assemble , causing cell lysis
What is a + ssRNA virus
viruses that contain a single strand of RNA that is a sense strand. It is used directly as mRNA for translation into proteins at the ribosomes
what is the sense strand in +ssRNA used for
used directly as mRNA for translation
What is - ssRNA virus
single strand of RNA in this virus is an anti sense strand
Is tobacco mv ++ssrna or -
+ssrna which means it can be directly translated into proteins at the ribosomes
is ebola –ssrna or +ssrna
- needs to be transcribed to produce mrna beforre translation
