What is DNA?
DNA, or deoxyribonucleic acid, is the codebook for building and maintaining living organisms. Within it lies the instructions for putting together the proteins in our bodies using amino acids. Through reproduction, all of or a portion from both organism’s DNA is passed down to the offspring. This allows slight deviations to maintain diversity while maintaining genetic continuity. All humans share over 99% of the same DNA, except for identical twins – they share the same DNA. This is because they came from the same fertilized egg, so the male’s and female’s DNA contributions are shared between the two.
While most DNA is found in cell nuclei, some can be found in the mitochondria. There are four chemical bases which are used to store information: adenine (A), cytosine (C), thymine (T), and guanine (G). The human genome comprises of about 3.2 billion bases of DNA. Other organisms vary. Bases are like letters in that different bases can be put together in different ways to produce information. Different combinations, like words, present different information for different functions. The bases make two letter words, or base pairs, and are each attached to a sugar molecule and a phosphate molecule. The combinations of pairs, sugar and phosphate molecules, are called nucleotides.
Long strands are formed with nucleotides. Two of these strands form the characteristic double helix spiral. The rungs of the structure are made with base pairs while the strands themselves consist of the sugar and phosphate molecules. When DNA replicates, the strands split and are used as templates enzymes to copy.