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What is Transcription and Translation?
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)
Difference between Transcription and Translation Biology
| 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 |
Functions of Transcription and Translation
Functions of Transcription
Production of mRNA - The process of transcription transcribes gene sequences from DNA into mRNA molecules that carry the genetic information copied from the DNA, delivering it to the cytoplasm and providing a template for translation.
Regulation of Gene Expression - Regulatory mechanisms in the transcription process control the rate of transcription of genes, thereby affecting the number of specific proteins produced in the cell.
Production of Many Types of RNA - In addition to mRNA, the transcription process produces other types of RNA molecules such as transfer RNA (tRNA) and ribosomal RNA (rRNA).Functions of Translation
Synthesize Proteins - The translation process converts the genetic information of mRNA into the amino acid sequence of proteins.
Regulation of Protein Function - Regulation can occur during translation, such as post-translational modifications such as post-translational splicing, phosphorylation, and methylation, which can affect the structure and function of proteins.
Generation of Protein Diversity - mRNAs of the same gene may undergo splice variants, i.e., different splicing patterns result in the production of different mRNA molecules that encode different proteins.
Association of Transcription and Translation
Transcribed RNA acts as a Template for Translation
Gene transcription produces mRNA molecules that are direct templates for translation. mRNA carries genetic information copied from DNA, where codon sequences indicate a specific order of amino acids. During translation, the ribosome reads the codons on the mRNA and joins the appropriate amino acids to form a protein chain based on the sequence of the codons.Transcriptional Regulation Affects Translation
In the regulation of gene expression, there is an interaction between transcription and translation. Transcriptional regulators can control the rate of transcription of a gene, which in turn affects the amount of mRNA produced.Transcriptional Modifications Affect Translation Efficiency
Modifications that occur during transcription can affect the efficiency and accuracy of translation. For example, post-transcriptional modifications such as splicing, RNA modification, and RNA degradation can affect the stability, structure, and readability of mRNA, thereby affecting translation.
Reference
- Niederholtmeyer H, et al. Real-time mRNA measurement during an in vitro transcription and translation reaction using binary probes[J]. ACS synthetic biology, 2013, 2(8): 411-417.
* Only for research. Not suitable for any diagnostic or therapeutic use.
