In this article we will discuss about the biological significance of DNA and RNA.
DNA usually includes two nucleotide polymers joined together by the matching or complementary shapes of their bases. The relationship between bases in a DNA double helix is a lock and key relationship.
The four bases of DNA can interlock to form two kinds of base pairs i.e., G with C and A with T. This kind of interlocking is the basis for DNA reproduction which in turn is the basis for reproduction in bacteria, plants, animals and man including every turning things.
Life depends on a balanced relationship between reproduction, structure and function. All turning things e.g., bacteria, plants, animals and man depends on the relationship between DNA and proteins. DNA is for reproduction whereas protein is for structure and function.
Although DNA is the basis of life, the relationship between DNA and protein is fundamentally a simple one called translation. Living cells are able to translate the chain of bases along inherited DNA molecules into the chain of amino acid, R-group along protein molecules.
The tiny egg cell from which a human life begins contains no blood and none of the blood’s oxygen carrying protein, haemoglobin. However, the egg cell does contain DNA reproduced by base pairing from parent molecules.
During development the DNA of blood forming cells open up (uncoils) and matches amino acids with DNA bases to make haemoglobin, a process called translation.
In the translation process, each amino acid is given a triplet name of three DNA letters as shown below:
The chain of DNA bases directing production of one protein can be called a gene. The typical protein consists of 500 amino acids and thus the typical gene will include 500×3 (1500) bases. A change in DNA changes protein and in turn hereditary characters. Atomic, Cosmic and U.V. radiation can cause changes in DNA (called mutations). The atomic fall out or radioactive element accumulating in food could also cause various genetic defects.
Inherited DNA molecules direct the production of specific proteins which are usually related to some particular hereditary character. The simple diagram below expresses the relationship between DNA, proteins and hereditary character.