The difference between transcription and translation is an important topic in science that often arrests attention. In this article, we will take a look at the following:
- What transcription is,
- What translation is, and
- Differences between transcription and translation.
Transcription involves the synthesis of mRNA from DNA through the help of an enzyme known as RNA polymerase. In other words, it involves the synthesis of RNA from a DNA. In this process, the code in the DNA is being converted into a RNA code that complements it. Only a segment of the DNA molecule (known as the “transcription unit”) is transcribed.
Translation involves the conversion of mRNA into an amino acid which is a polypeptide. In other words, it involves the synthesis of protein from an mRNA template. In this template, the mRNA undergoes conversion into an amino acid. Translation takes place in the ribosome.
There are a number of processes that differentiate transcription from translation. Each of these processes shall be discussed below in order to point out the differences between these two processes.
Transcription starts with the binding of RNA polymerase to the promoter region of the DNA structure. The binding between the transcription factors and RNA polymerase to the promoter leads to the formation of a complex referred to as the transcription initiation process. A core region like TATA box is found in the promoter. This is the point where the complex binds. The RNA polymerase unwinds the DNA at this stage.
Translation on the other hand starts with the formation of the initiation complex. Here, the ribosome subunit, IF1, IF2 and IF3 (i.e. the three initiation factors) and methionine (which carries t-RNA) all bind to th
e mRNA found near the AUG start codon.
Transcription process involves the transversal of the template strand of DNA in 3’ to 5’ direction by the RNA polymerase. This led to the production of a complementary RNA strand in 5’ to 3’ direction. The DNA strand that has undergone transcription rewinds to form a double helix as the RNA polymerase advances.
In translation, the aminoacyl t-RNA that’s coming in binds to the codon at A-site. This leads to the formation of a peptide bond between the new amino acid formed and the growing chain. In order to prepare for the next amino acid, the peptide moves one codon position thereby making the process to proceed in a 5’ to 3’ direction.
In eukaryotes, transcription takes place in the nucleus.
Translation on the other hand takes place in the ribosomes of eukaryotes. These ribosomes are found on the rough endoplasmic membrane located in the cytoplasm.
Termination process in transcription occurring in prokaryotes can either be Rho-independent or Rho-dependent. In eukaryotes, the RNA nascent transcript is released whenever the termination process is encountered. This is poly-adenylated.
In translation, the ribosome is disassembled and releases the polypeptide whenever it comes across one of the three stop condons.
The RNA transcript is the end product of transcription. The transcript can form any of the following; mRNA, tRNA, rRNA and microRNA. The mRNA often formed in prokaryotes is polycistronic while that formed in eukaryotes is monocistronic.
The polypeptide chain is the end product of translation. It folds and undergoes modifications to form a functional protein.
During the modification process that occurs after transcription in eukaryotes, a 5’ cap and a 3’ poly tail are added while the introns are spliced out. This process does not occur in prokaryotes.
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In translation on the other hand, some post modification processes occur. These include phosphorylation, formation of disulfide bridges, SUMOylation amongst others.
Transcription is inhibited by an antibacterial (known as rifampicin) and antifungal (known as 8-Hydroxyquinoline).
Translation is inhibited by chloramphenicol, erythromycin, streptomycin, puromycin, anisomycin and cycloheximide.
Measurement And Detection Methods
Methods used for measurement and detection in transcription include DNA microarray, In-situ hybridization, RNA-Seq, RT-PCR and Nothern blot.
Western blotting, enzyme assay, metabolic labelling, proteomics, protein sequencing and immunoblotting are used for measuring and detecting in translation.
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