What is DNA?

DNA is the chemical mostly inside the nucleus of the cell that carries biological instructions generation after generation.

Biological instruction means hereditary or genetic information used in the day to day functioning of all living organisms (including some of the viruses) and development of new young ones.

DNA is a short form of Deoxyribose Nucleic Acid. What these three words mean is given below.

D Deoxyribose A pentose sugar (with 5 carbons), does not have oxygen atom at the 2’ carbon
N Nucleic So named because these molecules were first identified in the nucleus of the cell
A Acid (phosphoric acid ) Out of three reactive hydroxyl groups of the phosphoric acid, two are used for DNA backbone formation or DNA chain formation. The third one gives the DNA an acidic property

Who discovered DNA?

Aristotle concluded that one generation transmits some of its characters to the next one. It was Gregor Mendel (1860) who described fundamental principles of inheritance. He called factor, to what we now call gene.

In late 1800s Frederich Miescher observed DNA for the first time.

There was debate on the issue that whether DNA is really a genetic information carrier? Reason to raise this issue was “structure of DNA”. It was simple, so it was hard to agree that it could play many completed roles. Instead protein was the major candidate for the title because it has complicated structure and variety of forms.

Later on it was proved that only DNA is the genetic material. Its importance and structure was revealed by efforts of many scientists like Watson and Crick, Maurice Wilkins and Rosalind Franklin.

Where DNA is located or found?

DNA is located mostly inside the nucleus of the cell. Each cell contains a lot of DNA, at actual size, a human cell’s DNA totals about 3 feet in length. A typical cell size is 10 µm. How does that entire DNA fit into a cell? So the solution for the problem is chromosome. This DNA is referred as nuclear DNA.

Sometimes DNA also found in cell structures like mitochondria (referred as mitochondrial DNA or mtDNA), chloroplast (referred as chloroplast DNA or ctDNA) and centrioles (referred as centriolar DNA).

Functions or uses of DNA

  • Contains hereditary or genetic or biological information, which is necessary for an individual to live and reproduce.
  • This information is passed on to next generations.
  • With the more understanding of DNA, technologies like recombinant DNA technology have been developed. Such technologies have applications in many areas such as agriculture, animal science, medicine etc.

Components of DNA

To know of what DNA is made up of visit the page DNA components. It will give complete information on the topic.

Structure of DNA or DNA Double Helix

To know double helical structure of DNA visit the page. It provides sufficient information about the topic.

Equivalence rule or Chargaff’s rule.

The total amount of purines equates to the total amount of pyrimidines (have a 1:1 ratio), it is the Equivalence rule or Chargaff’s rule.

The number of adenine bases equals the number of thymine bases.

The number of guanine bases equals the number of cytosine bases.