Tag: bio-chemistry

Reverse transcription is the process of generating a complementary DNA (cDNA) from an RNA template. The enzyme used is called the reverse transcriptase (RT).

The central dogma of molecular biology says DNA, i.e., deoxyribonucleic acid is replicated first to form a copy of DNA. This process is known as DNA replication and is catalyzed by an enzyme called as DNA polymerase (DNA dependent DNA polymerase). This replicated DNA is then transcribed to form an mRNA (messenger RNA molecule). This process is referred as transcription and this is carried out by an enzyme called as RNA polymerase (DNA dependent RNA polymerase), finally the mRNA is translated into a protein.This process is carried out by ribosomes where amino acids are incorporated. This process is known as translation. Francis Crick proposed this concept of central dogma in molecular biology which states that genetic information flows from DNA->DNA->protein. In some viruses, the flow of information is in reverse direction, i.e., from RNA to DNA. This process is known as reverse central dogma or reverse transcription. It takes place in viruses, acellular organisms where RNA replicates via a DNA intermediate. A complimentary DNA molecule is formed from genomic RNA with the help of an enzyme called reverse transcriptase ( RNA dependent DNA polymerase). Eg : HIV which is a retrovirus.

Teminism is basically a theory. It is also known as reverse transcription. It was discovered by Temin and Baltimore in 1978. In molecular biology, it explains RNA can act as template strand for DNA formation. So, it means that DNA can be synthesized from RNA.

(B) Reverse transcriptase enzyme is responsible for reverse transcription process which cDNA ( complementary DNA) is made from a RNA template.

Central dogma represents the sequential process of gene expression via four steps. Accordingly, the genetic information present in sequence of deoxyribonucleotides is transcribed into sequence of ribonucleotides in RNA which in turn serve as template to a polypeptide. The genetic information of DNA is self replicated via DNA replication where parent strand serves as template for synthesis of new DNA strands. Thus, transcription uses DNA strand template while translation uses RNA as template. But it is not always a linear process and can go upside down since reverse transcriptase enzyme synthesize DNA using RNA as template. It was first shown by Temin and Baltimore.

Tetracycline antibiotics are the protein inhibitors which inhibiting the binding of aminoacyl-tRNA to the mRNA-ribosome complex and prevents the translation (protein synthesis) as activated aminoacyl-tRNA bring amino acid in mRNA-ribosome complex.

Genetic information are transferred from nucleus to cytoplasm of cell through RNA. In eukaryotic cells, once precursor mRNA (pre-mRNA) has been transcribed from DNA, it is processed to mature mRNA. This removes its introns, non-coding sections, of the pre-mRNA. The mRNA is then exported from the nucleus to the cytoplasm, where it is bound to ribosomes and translated into its corresponding protein form with the help of tRNA. Ribonucleic acid (RNA) is a polymeric molecule. It is implicated in a varied sort of biological roles in coding, decoding, regulation, and expression of genes.

• Reverse transcriptase enzyme is an enzyme that is used to generate cDNA from RNA template through the reverse transcription process. This is seen in many retroviruses to replicate their genomes.
  
• DNA polymerase enzyme helps in DNA synthesis using DNA template, a process called replication.
  
• DNA ligase is used to join DNA fragments during DNA repair or its replication.
  

Retroviruses operate a central dogma reverse. RNA of these viruses first synthesis DNA through reverse transcriptase or RNA dependent DNA polymerase. This DNA synthesised on RNA template is called c-DNA or retroposons.