The Central Dogma
The central dogma is a principle describing the transfer of molecular information in the Nucleus of the DNA. It gives detailed instructions on the processes involved in the conversion of DNA information into a final functional product, the protein. The central dogma was proposed by Francis Crick in 1958 after discovering the DNA structure (Liu et al., 2018). Crick uses the principle of central dogma in suggesting that the DNA has all genetic information required to make all proteins in the body, involving the transfer of specific information from DNA to RNA that finally creates the functional proteins which carry the genetic code in a process known as gene expression (Liu et al., 2018). The flow of this genetic information is irreversible once the genetic information passes from DNA to RNA. Genetic information from DNA controls the type of proteins formed in an organism since it determines the specific traits in different species. The formation of functional proteins through gene expression involves the replication transcription and translation of DNA, where transcription and translation are the key steps.
tailored to your instructions
for only $13.00 $11.05/page
This is a process involved in the formation of messenger RNA (mRNA) through the re-writing and copying of DNA molecules. While DNA stores genetic material in a cell’s nucleus for long-term referencing, RNA copies the same material but distributes it to other cells since it can easily exit from the nucleus. Although the information copied from DNA is the same, it differs because it’s only a representation of the actual DNA sequence. For transcription to take place, three stages are involved namely, initiation, elongation, and termination (Liu et al., 2018). The first stage is the initiation process which involves the binding of an enzyme known as RNA polymerase and other assisting transcription factors to a specific DNA promoter and enhancer sequences that guide the RNA polymerase to the right site. When the RNA polymerase binds to the promoter sequence, it unwinds a part of the double helix in the DNA sequence to expose the bases of each strand.
The process then moves on to elongation where RNA polymerase starts the synthesis of mRNA by reading and matching complementary bases. Elongation occurs when nucleotides are added to the mRNA strand and are attached to the unwound DNA strand where the Adenine (A) base of DNA pairs with Uracil (U) base in RNA (Liu et al., 2018). The process of transcription ends with the termination stage in which the mRNA synthesis completes to form an independent strand that unbinds from the DNA sequence. These independent copies are used as blueprints in synthesizing proteins during the translation process.
In the translation process, the genetic code carried by the mRNA molecule is synthesized and read to produce a particular sequence of amino acids. The process occurs in the ribosomes, which is the site for protein synthesis of both prokaryotic and eukaryotic cells of organisms. Translation requires the mRNA, transfer RNA (tRNA), and ribosomes which enhance the stages of initiation, elongation, and termination. During the translation process, mRNA nucleotides are referred to as codons which are set in combinations of three letters, each representing a specific amino acid. The codons have complementary anticodons contained in tRNA which guide the amino acids to the appropriate site for translation.
Initiation involves the binding of small ribosomal units to the beginning of the mRNA sequence where tRNA binds methionine to the start codon of the sequence (Liu et al., 2018). The initiation process is completed when large ribosomal subunits attach forming a complete complex. In the elongation process, ribosomes continue the translation of all codons and corresponding amino acids are added to the chain which is connected by a peptide bond. When all codons are read, the termination process occurs where ribosomes reach the stop codon which is not recognizable tRNA molecules marking the end of translation. New proteins are released and the translation complex breaks apart.
Liu, C. C., Jewett, M. C., Chin, J. W., & Voigt, C. A. (2018). Toward an orthogonal central dogma. Nature Chemical Biology, 14(2), 103-106. Web.