Transcription is the synthesis of RNA from a DNA template, where the code in the DNA is converted into a complementary RNA code. Translation is the synthesis of a protein from an mRNA template, where the code in the mRNA is converted to the amino acid sequence in the protein.
Fig 1. Process of transcription and translation. (Niederholtmeyer et al., 2013)
| Item | Transcription | Translation |
| Purpose | The purpose of transcription is to make RNA copies of individual genes that the cell can use for biochemistry. | The purpose of translation is to synthesize proteins that are used for millions of cellular functions. |
| what is transcription in biology / what is translation in biology | Transcription is the first step in gene expression in which RNA polymers are produced from the DNA template. The reaction is catalyzed by enzymes called RNA polymerases, and the RNA polymers are antiparallel and complementary to the DNA template. The segment of DNA that encodes the RNA transcript is called a transcription unit and may contain multiple genes. | Translation is the synthesis of a protein from an mRNA template. This is the second step in gene expression. Translation is the process of decoding the "order of bases" in a mature messenger RNA molecule according to the central law of the genetic code and generating the corresponding sequence of specific amino acids. |
| Where the process takes place | It occurs in the nucleus. | It occurs in the cytoplasm. |
| Initiation | Occurs when an RNA polymerase protein binds to a promoter in DNA and forms a transcription start complex. The promoter indicates the exact location of the start of transcription. | Occurs when ribosomal subunits, initiation factors, and t-RNA bind mRNA near the AUG start codon. |
| Elongation | During transcription, the RNA polymerase, after an initial failed attempt, passes through the DNA template strand in the 3' to 5' direction, producing a complementary RNA strand in the 5' to 3' direction. As the RNA polymerase advances, the transcribed DNA strand rewinds to form a double helix structure. | During translation, the incoming amino acid t-RNA binds to the codon at the A site (a 3-nucleotide sequence) and forms a peptide bond between the new amino acid and the growing strand. The peptide then moves one codon position in preparation for the next amino acid. Thus, the process proceeds along the 5' to 3' direction. |
| Termination | The RNA transcript is released and the polymerase detaches from the DNA. The DNA rewinds itself into a double helix structure and remains there throughout the process. | When the ribosome encounters one of the three termination codons, it breaks down the ribosome and releases the polypeptide. |
| End Product | mRNAs, tRNAs, rRNAs and non-coding RNAs (e.g. microRNAs) | Proteins |
Transcription converts DNA to RNA using RNA polymerase, while translation decodes mRNA into proteins via ribosomes. Transcription occurs in the nucleus, translation in the cytoplasm.
Promoters, enhancers, and transcription factors regulate initiation rates, while terminator sequences determine transcript length and stability in different systems.
Codon usage, ribosome binding sites, mRNA secondary structures, and initiation factors collectively determine translation fidelity and protein yield.
Strategic 5'UTR design, codon optimization, poly-A tail length adjustment, and secondary structure minimization significantly improve translational efficiency.
miRNAs, siRNAs, and long non-coding RNAs fine-tune expression through transcriptional and post-transcriptional mechanisms in complex regulatory networks.
Cell-free expression systems and engineered genetic circuits replicate central dogma processes for protein production and genetic network design.
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