All the living organisms in our planet containsthe molecular instructions for life, calleddeoxyribonucleic acid or DNA. It is a self-replicatingmolecule or material present as the main constituent inchromosomes. It encodes the genetic instructions usedin the development and functioning of all known livingorganisms and many viruses.DNA is made up of two polynucleotide strands.Polynucleotide strands twist around each other, forminga shape that looks like a ladder called a double helix.
Thetwo polynucleotide strands run antiparallelto each otherwith nitrogenous bases this means that the stands run inopposite directions, parallel to one another. But thequestion is how does it holds its formation?The strands of DNA are held together throughHydrogen bonding that is brought on by electrostatic interactions. This force plays a vitalrole in DNA Replication. It does not only hold the molecule together but gives the moleculestructure and strength. The “backbone” of each helix is formed from alternating deoxyriboseand phosphate subunits.
Each deoxyribose is connected to a base that extends between thetwo backbones.The four nucleotide bases are given the symbols A (adenine), C (cytosine), G(guanine), and T (thymine). The sequence of the bases determines the genetic characteristicsof the parent organism. The order of the four bases varies in each strand, but the pairingbetween bases is always the same.
C is attracted to G and A is attracted to T, which helps inpreserving the order of bases in cell division (mitosis) and passing on the correct geneticinformation.For guanine and cytosine, there are three cases in which hydrogen atoms areattracted to nearby nitrogen and oxygen atoms. The interactions between two bases can bemodelled as electrostatic interactions in which electrons from the oxygen and nitrogenatoms are negative, and are attracted to the exposed positive nuclei of the nearby hydrogenatoms.
These hydrogen bonds are relatively weak, but their sum is strong enough to hold thetwo DNA strands together.Therefore, DNA strands are positioned close to one another are not because of formalchemical bonds. Instead, it is because of the Electrostatic interactions which is the Hydrogenbonds that hold it together.