Virology

Question 1

Properties of viruses
Smallest obligate intracellular infective agents contain either DNA Or RNA

Answer 1

No metabolic activity outside living org
No cellular organisation, lack enzymes for protein nucleic acid synthesis
Multiply by complex process
Don’t grow in inanimate media
Resistant to antibiotics

Question 2

Structure of 🦠viruses

Answer 2

1) nucleic acid core genome
2) capsid - protein coat covers genome nucleic acid + capsid = nucleocapsid
Capsid contain large no.of polypeptide or protein subunits called capsomers
3) envelope- lipoprotein in nature
Projectile spike on envelop-peplomers

Question 3

Function of capsid

Answer 3

-Protects the nucleic acid or genome
-Forms impenetrable shell around it
-Introduce viral genome into host cell by absorbing readily to cell surface
-Play key role in attachment of virus

Question 4

Symmetry of capsid

Answer 4

1) Icosahedral/cuboid - polygon with 12 corners in shape of equilateral 🔺
Ex: papova,adeno,herpes,toga,picorna
2) Helical - coli together form spiral
Ex: enveloped RNA viruses, paramyxo bunya, rhabdovirus
3) complex symmetry - pox virus

Question 5

Shapes of viruses
Pox, rabies, rota ,adeno, ebola

Answer 5

Pox - brick shaped
Rabies - Bullet
Rota virus - wheel shape
Adeno virus - spce vehicle shape
Ebola virus - filamentous

Question 6

Replication of viruses
Steps - A PUB MR

Answer 6

1) attachment
2) penetration - viropexis membrane
3) uncoating - lysosomal enzymes
4) biosynthesis
5) maturation- genome +capsid= virion
6) release: enve~budd; non enve~lysis

Question 7

Biosynthesis steps 4

Answer 7

1) transcription of mRNA-viral genome 2) translation of mRNA- nonstructural proteins synthesis virus components
3) replication of viral genome
4) synthesis of late proteins or structural proteins produce capsids

Question 8

Cultivation of viruses 3

Answer 8

1) animal inoculation -research
2) embryonated egg inoculation
3) tissue culture - organ, explant, cell
Cell culture 3 types ~ 1°cell culture, 2n diploid cell stain, continuous cell lines

Question 9

Embryonated egg inoculation -

Good pasture used hens egg for cultivation of viruses. After inoculation eggs incubated for 2-9days

Answer 9

Egg inoculated by several routes :
1) chorioallantoic membrane -pox
2) amniotic cavity - viral vaccines for influenza, yellow fever,rabies viruses
3) amniotic sac - isolation of influenza
4) yolk sac - inoculation of virus, bact