JKSET Environmental Sciences 2018

JKSET Cut-off Marks

Molecular feature of CORONAVIRUSES.
-Coronaviruses utilize RNA dependent RNA synthesis to generate mRNA to be transcribed by the host genome.
-The RNA(+) strand is used to make the enzyme RNA dependent RNA Polymerase
RNA(+) strand is replicated to RNA(-) strand
-The RNA(-) strand is used to
1 make sub genomic mRNAs. by transcribing from the RNA(-) strand from multiple start sites and in multiple open reading frames(ORFs)
2 make more RNA(+) strand via replication
- virion progeny is made via the Secretary pathway(roughER, GOLGI apparatus and exocytosis) .
Coronaviruses replication entails.
1 ribosomes frame shift during genome translation
2 synthesis of both genomic and multiple sub genomic RNA species
- the HALLMARK of coronavirus transcription is the Production of multiple sub genomic mRNAs
that contain sequence corresponding to both ends of the genome
Nonstructural proteins that have a critical role in viral RNA synthesis
coronaviruses genome size ~30000 nucleotide