Why Our Proteins Are Determined By Our DNA?

The central dogma of molecular biology – DNA molecule stores all genetic information. From DNA to mRNA transcription. Protein biosynthesis translation.

When it comes to proteins, DNA (deoxyribonucleic acid) plays a huge role – it is the fundamental source of genetic information that is necessary for protein synthesis. DNA is a double helix formed of two polynucleotide chains. Each DNA nucleotide consists of phosphoric acid residue, carbohydrate deoxyribose, and a nitrogenous base. There are four types of nitrogenous bases: adenine (A), thymine (T), guanine (G), cytosine (C) (Fig. 1). DNA is found in each cell, mainly in its nucleus. It contains (in its sequence of nitrogen bases) genetic information encoded by triplet code, which is transmitted to other cells during processes like protein synthesis and DNA replication. Whereas, proteins are high molecular weight organic matter consisting of amino acids. All amino acids have two identical functional groups: the amino group (- NH2) and carboxyl (- COOH) but differ in the R group (radicals). This part of the molecule can be varied, from one hydrogen atom to complex cyclic compounds. Amino acids interconnect with the peptide link. This bond is formed between one amino acid carboxy group and another amino acid amino group. Such conjugated amino acids form a peptide, and the whole chain is a polypeptide. Regardless of the type of organism or cell, all proteins consist of the same 20 amino acids. By combining amino acids in a different order and number, they form an infinite variety of protein molecules, which carry out different functions.

In the first segment of this essay, I will talk about DNA, the second section will examine transcription process. In the third section, I will analyse protein synthesis (translation). All these segments combined will clarify the question stated in the title – why our DNA determines our proteins.