DNA (Deoxyribonucleic acid)

DNA (Deoxyribonucleic acid) derives its name from its structure, sugar and phosphate, which form the backbone of DNA. Here deoxyribose refers to the sugar, and nucleic acid refers to the bases or Phosphate. DNA is an integral part of our body and is responsible for defining who we are. In addition, it is responsible for the growth and development of our bodies.

What is DNA (Deoxyribonucleic acid)?

DNA (Deoxyribonucleic acid) is an organic chemical comprising complex molecular structures. It is present in humans as well as in all other organisms. Every cell in a particular body possesses the same DNA located in the cell’s nucleus. In addition, a small amount of DNA is also present in the mitochondria. 

DNA is built of building blocks called nucleotides. It contains the structure, the genes of one’s unique self.

DNA (Deoxyribonucleic Acid) Composition

In 1869, the chemical components of DNA were discovered, but DNA’s role in genetic inheritance was not apparent until 1943. Nucleotides create DNA and every nucleotide consists of a sugar molecule, Nitrogen as the base and a Phosphategroup. 

DNA stores information in code made up of four Nitrogen chemical bases. They are:

• Purines

1. Adenine (A)
2. Guanine (G)

• Pyrimidines

1. Cytosine (C)
2. Thymine (T)

The DNA consists of sugar which is called 2-deoxyribose. Nitrogen as the base is attached to each sugar molecule.

A human DNA comprises more than 3 million bases, out of which over 99 per cent of the bases are the same in all humans. The arrangement of these bases represents the information on building and maintaining an organism. 

DNA (Deoxyribonucleic acid) also serves as a primary unit of heredity in organisms. It means the offspring inherits a portion of each parent’s DNA during reproduction. This transmission ensures continuity from one generation to another while still allowing slight changes, contributing to the diversity of life.  

A long chain of monomer nucleotides composes strands of a DNA molecule. DNA nucleotide consists of a deoxyribose sugar molecule fastened to a Phosphate group and one of the four Nitrogen as the bases. The Phosphate of one nucleotide and the sugar of the other form a covalent bond. This bond is responsible for bonding between the two nucleotides. The nitrogenous bases come from the Phosphate-sugar backbone. In DNA, Adenine bonds only with thymine and cytosine with guanine.

Discovery of DNA (Deoxyribonucleic Acid)

In the late 1860s, Swiss chemist Friedrich Miescher identified what DNA (Deoxyribonucleic acid) is. Later on, a series of research was conducted by Phoebus Levene and Erwin Chargaff, revealing additional details about DNA molecules, such as their primary chemical component and how they join with each other. Without this groundwork, Watson and Crick may never have been able to conclude in 1953 that the DNA molecule’s structure is a three-dimensional double helix.

What does DNA (Deoxyribonucleic Acid) do?

Deoxyribonucleic acid or DNA contains genetic information and instructions on protein synthesis. They are responsible for a body’s growth, development and reproduction. A sequence of base nucleotides stores the data passing from one generation to the other. It is a crucial part of reproduction and is responsible for genetic heredity by passing down DNA from parents to the offspring.

DNA Double Helix Structure

DNA bases pair up to form units called base pairs. The sequence of the bases pairs is A with T and C with G. They are attached to a phosphate molecule and a sugar molecule. Nitrogen as the base along with sugar and Phosphate is known as a nucleotide. 

The arrangement of Nucleotides forms a spiral in two long strands called a double helix. The DNA deoxyribonucleic acid diagram is similar to a ladder. Base pairs represent the ladder’s rungs, and the Phosphate and sugar molecules represent the vertical side pieces of the ladder.

Major and Minor Grooves of the DNA

• Asymmetry of grooves results from the geometrical configuration of the Phosphate, sugar and base group bonds. The bonds force the base groups to attach at a 120-degree angle instead of 180 degrees.
• The grooves expose the edges of the base and are used to tell the base sequence of a particular DNA (Deoxyribonucleic acid) molecule.
• It is critical to recognise such possibilities as proteins must identify specific DNA sequences of binding for the proper functioning of the body and cell.

Where is DNA found?

The perfect location of DNA (Deoxyribonucleic acid) depends on the cell type. 

Eukaryotic Cells

Eukaryotic Cells have a nucleus bound by a membrane and many other membrane-bound structures called organelles. Such cells are present in humans and many other organisms. In eukaryotic cells, the nucleus encompasses DNA. In addition, the organelles called mitochondria (a cell’s powerhouse) contains a slight trace of DNA (Deoxyribonucleic acid). 

Low nucleus space results in condensing DNA into packages. Packaging is found in different stages. The final product is known as Chromosome.

Prokaryotic Cells

Bacteria contain prokaryotic cells. Such cells don’t have a nucleus or organelles. Instead, DNA (Deoxyribonucleic acid) resides in the middle of the cell called a nucleoid and is coiled tightly.

Properties of DNA (Deoxyribonucleic Acid)

DNA properties define what is DNA (Deoxyribonucleic acid) to a large extent. The properties include:

• Helices of DNA can be either right or left-handed. The right-handed helix of the B-conformation of DNA is the most stable.
• The two strands of DNA separate on heating and hybridise on cooling.
• At melting temperature (Tm), the two strands of DNA separate. The melting temperature remains constant for each specific sequence.
• Presence of high C-G content in the B sample of DNA results in a higher melting point because a C-G pair has three hydrogen bonds.
• In all organisms’ DNA (Deoxyribonucleic acid), bases encode the sequence of amino acids in every protein. 

Conclusion

DNA (Deoxyribonucleic acid) is an essential molecular structure that contains genetic information. It is a vital part that instructs a body to grow, develop and reproduce. In addition, it includes instructions for the cells to produce protein affecting many different functions and processes in our body. Thus, DNA is the base of who we are.