The Role of DNA: Exploring Its Types and Functions in Living Organisms

Except for red blood cells, almost every cell in your body contains DNA or genetic code that makes us “us”. DNA contains instructions for the development, growth, reproduction and function of the entire life. Amazingly, if all the DNA present in the human body is unraveled, it will be so long that it can reach the sun and return to the earth 300 times.

(Read more - Gene therapy)

Differences in the genetic code are the reason why a person has blue eyes instead of brown or why some people are susceptible to certain diseases or why birds have only two wings and why giraffes have long necks. DNA is a complex, long chain-like molecule that encodes the genetic characteristics of a living organism. In most plants and animals, DNA is found in the form of compact structures along with ribonucleic acid and proteins called chromosomes residing in the cell nucleus.Large compact DNA molecules associated with proteins called chromatin, are mostly present inside the nucleus. We also get our mitochondrial DNA, mtDNA, which we get only from our mother and not from our father. Mitochondrial DNA is located outside the nucleus of the cell.

At the time of conception, a child receives DNA from both the father and the mother. We have 23 pairs of maternal-paternal chromosomes. One of each pair was received from the father and one from the mother. These 23 pairs of chromosomes are known as nuclear DNA because they reside in the nucleus of every cell in our body, except red blood cells. The 23rd chromosome is known as the sex chromosome. It is inherited, along with the other chromosomes, one from the father and one from the mother. The 23rd chromosome from the mother is always the X. From the father, a person receives either an X chromosome or a Y chromosome. The chromosome inherited from the father determines their sex. An X from the father results in an XX combination, a female baby is born. A Y from the father results in an XY combination, a male baby is born.

(Read more - Hepatitis B Test)

DNA is a ladder-like molecule that appears curved, giving it a unique shape called a double helix. DNA is usually a double-stranded polymer of nucleotides, although single-stranded DNA is also found. Each of the two strands is a long sequence of nucleotides, or individual units made up of the following elements -
Phosphate molecule - A sugar molecule called deoxyribose, which has five carbons
Nitrogen-containing rings - There are four types of nitrogen-containing rings called bases

• Adenine (A)
• Cytosine (C)
• Guanine (G)
• Thymine (T)

The order of these four bases makes up the genetic code, our instructions for life. The order of these bases is called the DNA sequence. These "letters" occur in specific sequences within your genes. They contain instructions for making a particular protein, for a particular cell, at a particular time.

The bases of the two strands of DNA are stuck together to form a ladder-like shape. Within the ladder, A always sticks to T and G always sticks to C to form the "ladder rung." The length of this ladder-like shape of DNA is made up of sugar and phosphate groups.

(Read more - Karyotype Test)

The functions of DNA were first isolated and chemically discovered before it was understood. When it became clear that DNA is a material that is passed from one generation to the next, its functions began to be investigated. DNA's main role in the cell is the long-term storage of information. It is often compared to a blueprint, because it contains instructions for building other components of the cell, such as proteins and RNA molecules. The DNA segments containing genetic information are called genes, but other DNA sequences have structural purposes or they regulate the expression of genetic information. In eukaryotes such as animals and plants, DNA is stored inside the cell's nucleus, while in prokaryotes such as bacteria and archaea, DNA is in the cell's cytoplasm.

Unlike enzymes, DNA does not act directly on other molecules. Rather, various enzymes act on DNA and copy its information into more DNA, either in DNA replication or in transcription into proteins. Other proteins such as histones are involved in packaging DNA or repairing damage to DNA that would otherwise cause mutations. One of the major functions of DNA is to encode the sequence of amino acid residues in proteins using the genetic code. To read the genetic code, cells make a copy of a stretch of DNA in the nucleic acid RNA. These RNA copies can be used to direct protein synthesis, but they can also be used directly as parts of ribosomes or spliceosomes.

(Read more -Cytomegalovirus (CMV) Test)

DNA (deoxyribonucleic acid) is a molecule that stores and transmits genetic information in all living organisms. It is arranged in a double-helix structure, consisting of four types of nucleotides: adenine (A), thymine (T), guanine (G), and cytosine (C). These nucleotides pair up in a specific order to form genes that control the development, growth, and functions of an organism. DNA is found in the nucleus of cells and is organized as chromosomes. When DNA is copied, it is transferred to new cells, thereby transmitting genetic information from generation to generation. DNA sequencing and analysis play an important role in medicine, biotechnology, and forensic science.