RIBONUCLEIC ACID (RNA)
Transcription and Translation are very common terms in Biology. Transcription is the first step of gene expression process and it is the synthesis from RNA from DNA where the code in DNA is converted into complementary RNA code. Translation is the synthesis of protein from mRNA.Transcription: It is the first step of gene expression process in which
synthesis of the genetic instructions written in the genome.
Transcription occurs in the nucleus. The enzymes responsible for transcription are
transcriptase and RNA polymerase. It occurs in the G1 and G2 phases of the cell cycle.
Transcription comprises the unwinding and splitting of those genes which are to be transcribed. Transcribed RNA strand gets separated from its DNA template strand.
The product move from the nucleus to the
cytoplasm and no primer is required and gets degraded after their function is completed. It results in the formation of the RNA molecule from a section of one strand which includes tRNA, rRNA, mRNA and non-coding
RNA.
Translation: It synthesis the proteins, that are used for millions of cellular functions. Translation is the second step of the gene expression process. It synthesizes proteins from RNA which are copied from genes. A template is an mRNA. It occurs in the cytoplasm. The enzymes responsible for the
process are ribosomes. Translation occurs when ribosome sub-units, initiation factors, and t-RNA bind the mRNA near the AUG start codon and finally produces proteins. Translation is inhibited by anisomycin,
cycloheximide, chloramphenicol, tetracycline, streptomycin, erythromycin and puromycin.
Now, look at the difference between transcription and translation for complete knowledge.
Purpose - The purpose of transcription is to make RNA copies of individual genes that the cell can use in the biochemistry while the purpose of translation is to synthesize proteins which are used for cellular functions.
Occurrence - Transcription occurs in the nucleus while translation occurs
in the cytoplasm.
Enzyme - The enzymes responsible for the transcription are transcriptase and RNA polymerase and enzymes responsible for the translation process are ribosomes.
Template - Template in transcription is the genes in the genome whereas the template in translation is the mRNA.
Primer - Primer is not required in transcription while in translation primer is required.
Structure of RNA
Structure of RNA is different from that of DNA in three respects.
1. DNA is a double stranded -helix whereas RNA is mostly singlestranded-helix
2. RNA has the pyrimidine base uracil in the place of thymine of DNA
3. DNA has deoxyribose sugar whereas RNA has ribose sugar as given below:
Biological importance of RNA:
RNA are the main components of protein synthesis
In many viruses the RNA functions as the genetic material.
The rRNA present in the chromatin fibres initiates the
replicationof DNA
RNA is associated with memory storage functions in the brain.
DIFFERENCE BETWEEN DNA AND RNA