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Article by: Mavidhya
DNA or deoxyribonucleic acid forms the genetic blueprint for all living organisms. This polymer withholds the ability to synthesize thousands of proteins and useful components required for the growth and development of the body.
The information in DNA is stored as four chemical bases: Adenine, Cytosine, Guanine, and Thymine. The bases pair up with one other, Adenine with Thymine and Guanine with Cytosine. Each of these bases is attached to a 5-carbon sugar, deoxyribose, and a negatively charged phosphate group. This forms a nucleotide and repeating units of these nucleotides form our DNA.
Within the structure of DNA contains a region that does not encode amino acids called the ‘non-coding DNA’. A study suggests that 75% of human DNA is “junk”. The region forms an obscure nucleotide sequence which is considered non-functional in terms of protein synthesis. Non-coding DNA is the remains of evolutionary material, the material that had a change in the amount of DNA present. Consequently, the word ‘junk’ was associated with non-coding DNA.
However, according to a study by Oxford University, 8.2% of the human genome is functional. Approximately 1% of human DNA accounts for proteins essential for biological processes, while 7% acts as a regulatory element. Examples of regulatory elements include promoters which act as binding sites for Endoplasmic Reticulum for transcription, silencers which provide a binding site to restrain transcription, enhancers which oppose silencers and provide a binding site to activate transcription and forms specialized RNA molecules including transfer RNA and ribosomal RNA to assemble.
Another very important role of non-coding DNA is for the formation of telomeres. These
are found on the ends of each chromosome to preserve our genetic information. As mitosis continues, the telomeric DNA at each end will slowly degrade instead of the DNA. Once the telomeric DNA reaches an extreme length this will lead to a phenomenon called apoptosis or cell death, thus giving it the name ‘biological clock’ for it determines the lifespan of a cell.
Even though DNA contains millions of nucleotides with millions of chemical bases encoded within, most of its material is proven to be useless. This clearly shows that in fact all of the DNA is not as important as we thought it might be.
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