A. RNA Polymerase: It is a enzyme which engagged in the process
of transcription where the RNA is synthesized from the DNA
template.
The action of the RNA Polymerase is divided in three phases-
- Initiation:
After binding to the DNA, the RNA polymerase switches from a closed
complicated to an open complex. This change entails the separation
of the DNA strands to shape an unwound segment of DNA of about 13
bp, known as the "transcription bubble". Supercoiling performs an
crucial component in polymerase interest due to the unwinding and
rewinding of DNA. Because regions of DNA in the front of RNAP are
unwound, there are compensatory superb supercoils. Regions at the
back of RNAP are rewound and bad supercoils are present.
- Elongation:
The 17-bp transcriptional complicated has an 8-bp DNA-RNA hybrid,
that is, eight base-pairs involve the RNA transcript sure to the
DNA template strand.As transcription progresses, ribonucleotides
are introduced to the 3' stop of the RNA transcript and the RNAP
complicated actions along the DNA. The feature elongation prices in
prokaryotes and eukaryotes are about 10–100 neucleotides/sec.
- Termination:
Termination of RNA transcription can be rho-established or
rho-impartial. The former is based at the rho issue, which
destablizes the DNA-RNA heteroduplex and reasons RNA release.[20]
The latter, additionally referred to as intrinsic termination, is
based on a palindromic region of DNA. Transcribing the vicinity
reasons the formation of a "hairpin" shape from the RNA
transcription looping and binding upon itself. This hairpin
structure is regularly rich in G-C base-pairs, making it greater
solid than the DNA-RNA hybrid itself. As a end result, the eight bp
DNA-RNA hybrid inside the transcription complex shifts to a 4 bp
hybrid. These ultimate 4 base pairs are weak A-U base pairs, and
the complete RNA transcript will fall off the DNA.
B. No the RNA virus does not use the host cell RNA
polymerase.
The RNA virus genome carry its own PNA polymerase in its
genome,because the host RNA polymerase enzyme can not transcript
the dsRNA (virus RNA gemone) as the mRNA.So the virus carry its own
RNA Polymerase which is present inside the viral capsid to
synthesize mRNA and replicate its genome.