Central dogma can be defined as the framework of understanding the sequential transfer of information between information carrying biopolymers which are Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA) so as to obtain functional products (proteins). The paper focusses to discuss the basic structure of DNA, how it replicates, and RNA translation so as form proteins and changes in the DNA which may affect the translation of that information.
DNA is a nucleic acid that contains the instruction for the formation of proteins. DNA found in the nucleus is responsible for the formation of RNA while that in the mitochondria is known as non-chromosomal DNA. DNA is made up of deoxyribose sugars, phosphoric acid and the four nitrogenous bases: these two are purines adenine (A), guanine (G) while these two are pyrimidine thymine (T) and cytosine (C) which make the nucleosides (Campbell, 2007).
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DNA replication is the process whereby DNA duplicates itself in the nucleus. The strands of DNA are arranged in such a manner that they bind to specific bases. For replication to occur, the double helix strand must unzip with the aid of enzyme helicase which is essential for breaking the hydrogen bonds between the nucleosides, after unzipping a replication fork is obtained. The separated strands form the complementary strands for replication. Replication occurs when enzyme primase produces RNA primer which binds to the leading strand. DNA polymerase then binds to the complex formed adding a new complementary nucleotide so as to form mRNA (Campbell, 2007).
A gene is a portion of the DNA containing hereditary information when coded protein synthesis occurs. For proteins to be synthesized there must be gene expression. The first process is transcription of genetic code so as to form mRNA. The mRNA enters the cytoplasm and activates ribosomes with the aid of enzyme RNA polymerase leading to protein synthesis. Translation of the genetic code then occurs. mRNA moves into the cytoplasm attaches with polysomes exposing the complementary base of tRNA. With the help of tRNA different amino acids are carried to the ribosome. rRNA helps in the assembling of amino acids to protein molecules (Campbell, 2007).
Abnormalities in the genetic composition occur due to variations or mutations leading to genetic disorders. The various changes can either be substitution, deletion, duplication and insertion. Substitution occurs when a single nucleotide within a gene sequence is altered. Deletion occurs when a portion of the gene sequence is omitted. Insertion occurs when there is addition of a portion of the gene sequence causing change in the originality of the structure. Lastly duplication occurs when a similar portion of the gene attaches itself to a similar strand. All changes in the structure of the DNA bring a significant change to protein synthesis.
Campbell, M. K., & Farrell, S. O. (2007). Biochemistry . Pacific Grove, Calif: Brooks/Cole.