What is DNA?
Most people have become somewhat familiar with the term 'DNA' in the last decade but may still have many unanswered questions or confusion about precisely what DNA is and how it is important to us. There is also quite often confusion around the concepts of DNA and chromosomes - the distinction is an important one. A chromosome is comprised of DNA and has proteins attached to it. These chromosomes are found in your body's cells, which then contain this important genetic information held in the long strands of DNA.
Deoxyribonucleic Acid (DNA)
DNA stands for deoxyribonucleic acid and is important primarily because it is inherited material found in humans and most other organisms. Just how much of this information is inherited, however, is still under debate but scientific research has shown a great number of strong similarities in DNA between humans and also between humans and other animals, supporting inheritance and evolution. In fact, most cells in your body have the exact same DNA, which is found in the cell's nucleus or less abundantly in the cell's mitochondria. These two kinds of DNA are known as nuclear DNA and mitochondrial DNA, respectively. You may be curious to know how DNA is actually stored within cells. It is made up of four bases known as:- Adenine
- Guanine
- Cytosine
- Thymine
Billions of Bases
In human DNA, the number of bases is actually enormous. Consider that there are approximately three billion bases found in human DNA and that almost all of these are the same in each person. In fact, the order of these four bases - the DNA sequence - is responsible to build and sustain an individual. DNA can replicate, which means it creates copies of itself, an important feature. Every DNA strand is essentially a pattern for copying a specific sequence of bases.This copying mechanism is vital to ensure that every new cell created has a copy of the genetic material from the old cell. When DNA bases pair with one another, they form something called base pairs. In DNA, adenine pairs with thymine and guanine pairs with cytosine. Every base is also joined to a sugar molecule and a phosphate group. Together, the base, sugar and phosphate form a unit called a nucleotide. It is the nucleotides that are neatly arranged in two long strands that twist to form a double helix. To get an accurate mental image of DNA, try picturing a long ladder, where the base pairs constitute the rungs of the ladder and the phosphate and sugar molecules make up the vertical parts of the ladder.
