In order to truly answer the question of “What is DNA?” one has to go back to the elementary or high school biology classes. You’ll recall that there are elements called chromosomes in each cell of human body. To be more precise, each cell contains 23 pairs of chromosomes. You’ll be astonished to know that some 50 to 100 thousand genes are held within these chromosomes. Since each of these genes could actually take value from one of the two values of its parent cells, hence you can imagine the possible variability in this structure.
These genes are made up of what is called DNA that is Deoxyribose Nucleic Acids. Apart from these genes that carry very essential genetic information and only account for 2% of DNA’s structure, the rest of the 98% of DNA is still a mystery. Biologists actually call it junk DNA as there are no known proteins or traits that are coded or built by this part of DNA. This junk DNA as well as the genetic information carrying part only varies in structure owing to the presence of four nucleotide bases throughout the DNA in differing order and sequence.
Think of these four nucleotide bases in DNA as letters that form an alphabet. Just like the way the order of letters determines the meaning of the word that is formed, the sequence of these nucleotide bases concludes what information is available for the production of proteins that consequently take an active part in the formation and growth of body.
Most of the DNA is present within the nucleus of the cells. This is known as nuclear DNA. Mitochondria also hold modest quantity of DNA, which is termed as mitochondrial DNA. The latter is useful in tests related to someone’s distant maternal lineage.
What is really great about DNA is that it has a very autonomous self-replication mechanism in action. The replication process makes use of the two strands of DNA. Each of these strands acts as template and after going through a series of steps is converted into dual stranded DNA once again. This replication is very important because when the cell divides, the newly formed cell requires the same set of instructions for it to function and grow and the replicated DNA serves this purpose.
Summing up the answer for what is DNA, it could easily be said that it’s a well designed program spanning thousands of lines of codes that has instructions for everything that the cell needs to perform.