virus, viroids and prions Flashcards
Scrapie and Creutzfled-Jakob disease are examples of diseases caused by which 'non living' organism Viruses Viroids Bacteria Prions
Viruses, viroids and prions are NONLIVNG
Prions cause transmissible spongiform encephalopathies (TSEs) such as scrapie, Creutzfled-Jakob disease, and mad cow disease
true of false
viruses have ribosomes
FALSE
they dont have ribosoems so use cells own machinery
decriebe the structure of a virus
core nucleic acod with caspid protien coat and spiked glycoproteins and sometimes a lipid capsule
what does postvie strand RNA genome mean
gemoe can act directly as mRNA
negatvie strand = genome complementary to mRNA
what is a viroid? how does it compare with a prion
infectious agent WITWHOUT protein
infectious agents without nucleic acids - misfolds of proteins
Which of the following statements regarding viruses is INCORRECT?
A Can replicate and evolve but do not grow
B Have no ribosomes so cannot synthesise proteins
C Are insensitive to changes in the environment
D Can contain both DNA and RNA genomes in a single caspid
E Can only reproduce inside a living cell
OPTION D
they can contain EITHER DNA or RNA in a single capsid, not both!!
> but their genomes use both ss. and ds.
Which of the following is not a feature of viroids
A Infectious agents without protein
B Made of only single stranded RNA
C Replicates inside infected cells
D Affect all domains of life
E Infectious agent is 350 nucleotides in length
OPTION D
viroids only affect PLANTS
Which TSE used to affect around 30,000 cattle per year but is now virtually eradicated? Scrapie Bovine spongiform encephalopathy Creutzfeld-jakob disease Variant creutzfeld-jakob disease Fatal familial insomnia
OPTION B
aka mad cow disease
Which of the following is not true regarding Prions?
A Much smaller than viruses
B Very heat sensitive
C Very radiation resistant
D Mis-folded versions of normal cellular protein PrP
E Infectious agents without DNA or RNA
OPTION B
they are heat resistant
:-) classic sneaky word eh?
