Chapter 6- Acellular pathogens

obligate intracellular

what kind of parasite is a virus

DNA or RNA

what is the genetic composition of viruses

viron

complete, fully developed viral organism, with genetic material

capsid

protein coat made of capsomere subunits

envelope

phospholipid and protein coat only some viruses have

spikes

projection from outer surfaces and binding sites

helical virus

hollow, cylindrical shape that is helical. ex: rabies and ebola

helical

Rabies and ebola are examples of which shape of virus

polyhedral viruses

many sides, most are 20-sided triangular facet. ex: adenovirus and poliovirus

polyhedral

adenovirus and poliovirus are examples of which type of virus

enveloped viruses

roughly spherical

complex viruses

complicated structures (bacteriophages)

-virus

Genus names for viruses end with what suffix?

-viridae

Family names for viruses end with what suffix?

-ales

Order names for viruses end with what suffix?

viral species

group of viruses sharing same genetic information and ecological niche host

Class 1

double-stranded DNA, enveloped

Class 2

ss DNA + intermediate ds DNA to form transition to mRNA

Class 3

ds RNA similar to class 5 in replication

Class 4

ss RNA+, genome is mRNA

Class 5

ss RNA-, RNA replicase makes the positive sense strand, which is used as the mRNA template for more negative strand genomes

Class 6

ss RNA + with reverse transcriptase, replicates through DNA intermediate. Reverse transcriptase enzymes copy RNA onto DNA. ex: HIV

Class 7

ds DNA with reverse transcriptase. replicates through RNA intermediate with reverse transcriptase.

RNA dependent RNA polymerase

how does a virus multiply in the host cell’s cytoplasm?

ss RNA +

ss RNA -

ds RNA

Which viral groups need intermediates?

ss RNA + (sense)

viral RNA serves as mRNA for viral protein synthesis. genome can act immediately as mRNA and translate into proteins.

ss RNA- (antisense)

viral RNA is transcribed to a positive strand and to serve as mRNA for protein synthesis.

ds RNA

ss RNA is needed as an intermediate

attachment

entry

uncoating

biosynthesis

maturation release

steps of multiplication of animal viruses

attachment

viruses attach to cell membrane

entry

entry by receptor mediated endocytosis fusion

uncoating

separation of nucleic acids from capsid by either viral or host enzymes

biosynthesis

production of nucleic acids and proteins

maturation

nucleic acids and proteins assemble into the virus

release

release via budding (enveloped viruses) or rupture (non-enveloped viruses)

7 steps bitch

Multiplication and inheritance of retroviridae class 6

1

hiv attaches/fuses to the host cell

2

HIV RNA, reverse transcriptase, integrase, and other viral proteins enter the host cell

3

viral DNA is formed by reverse transcription (reverse transcriptase)

4

Viral DNA is transported across the nucleus and integrates into the host DNA

5

new viral RNA is used as genomic RNA and used to make viral proteins

6

new viral RNA and proteins move to cell surface and a new immature HIV forms

7

virus matures when protease releases the proteins that form the mature HIV

viroids

short pieces of naked RNA, consists of circular ssRNA, which doesn’t produce proteins. exists inside cells as particles of RNA lacking a capsid or envelope

Virusoid

viroids enclosed in a protein coat. only cause disease when plant cell is infected with a virus

prions

proteinaceous infectious particles

inherited and transmissible by ingestion and surgical instruments. ex: Creutzfeldt-Jakob disease