Second Scientific Article from our club. We'll publish each article after every two week.
Written by: S.M. SAD AL NAHIYAN Institution: Dhaka Shiksha Board Laboratory School& College Class: 10 Secretary of Publications of DSBLSC Science Club.
▪︎PREFACE: Deoxyribonucleic acid, more commonly known as DNA, is a complex molecule that contains all of the information necessary to build and maintain an organism. All living things have DNA within their cells. Nearly every cell in a multicellular organism possesses the full set of DNA required for that organism. The chemical DNA was first discovered in 1869, but its role in genetic inheritance was not demonstrated until 1943. In 1953 James Watson and Francis Crick, aided by the work of biophysicists Rosalind Franklin and Maurice Wilkins, determined that the structure of DNA is a double-helix polymer, a spiral consisting of two DNA strands wound around each other.
▪︎Where is DNA found?
The same set of DNA is found in the nucleus of every cell in our body. The DNA is so tightly coiled and packed that it is estimated the nucleus of each human cell can hold about 2 meters of DNA. The DNA exists in 46 separate segments within the nucleus; these segments are known as chromosomes.
Each chromosome has a partner that contains the same genes in almost the same sequence of DNA, one member of the chromosome pair or homolog came from the father and one came from the mother during fertilization. The chromosomes are what carry genes.
▪︎What does DNA look like?
The shape of DNA at the molecular level is thought to look like a gently twisting ladder. Each of the rungs on the lad
der represents a chemical bond between the chemicals that make up the DNA molecule. These chemicals are called nucleotides and include:
•Adenine (A); •Thymine (T); •Cytosine (C); and •Guanine (G).
▪︎Why is DNA important to every living thing?
DNA is vital for all living beings – even plants. It is important for an inheritance, coding for proteins, and the genetic instruction guide for life and its processes. DNA holds the instructions for an organism's or each cell's development and reproduction and ultimately death.
Multiple genes work for one trait in an organism, while in some cases a single gene controls several traits. Human eye color, hair nature, skin color, etc. are all controlled by genes. According to humans, the characteristics of other animals and plants are also controlled by genes located in their chromosomes. To carry chromosome genes from one generation to the next.
CLOSING: The next 50 years of the DNA story will be all about realizing the practical benefits of Crick and Watson’s discovery for humanity - in industry, medicine, food, and agriculture.
Source: Chemistry in Britain, Encyclopædia Britannica.
