Meaning of DNA (deoxyribonucleic Acid)

What is DNA (deoxyribonucleic acid):

DNA is the macromolecule basis of heredity. It is a nucleic acid that contains information on the hereditary characteristics of each living being and the sequences for the creation of amino acids that will generate vital proteins for the functioning of organisms.

DNA or DNA (for its acronym in English) is an acronym for deoxyribonucleic acid and has as its main function the storage of all the information necessary for the expression of certain characteristics, in segments called genes or packaged in chromosomes.

In addition, DNA transcribes the information of the amino acid sequences in RNA or ribonucleic acid, so that these instructions can be protected from the nucleus to the ribosomes, which will translate the information to create proteins (chains of amino acids).

Referring to the above, it can be seen that DNA is coding and RNA is not coding but they work together for the transmission of genetic information.

The DNA begins to be studied in the year 1868 by Friedrich Miescher who calls together with the RNA as nucleic acids. The description of DNA was first published in 1953 by Jamen Watson and Francis Crick, both winners of the 1962 Nobel Prize in Medicine.

DNA characteristics

The main characteristic of human DNA is its double helix structure, also known as helical.

Where is DNA located?

In prokaryotic cells (without a defined cell nucleus), the DNA is found in the cytosol, along with the other elements that float in it. Thus. its replication is immediate, that is, it does not need to resort to other processes to transmit genetic information at the time of cell division.

In eukaryotic cells (with a defined cell nucleus), the DNA is located in the cell nucleus. There are 2 ways in which DNA transmits genetic information within it:

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Before cell division: This replicates and is packaged with other molecules and proteins to form a larger molecule called a chromosome. In this way, during mitosis, the 2 daughter cells will carry a copy of the original DNA.

For protein translation or synthesis: the information of the sequences of 3 nitrogenous bases (codon) that will determine the functions of the proteins of the DNA of each organism needs the messenger ribonucleic acid (mRNA) to travel safely out of the nucleus, towards the ribosomes.

What are the functions of DNA?

DNA is characterized because it must fulfill 2 fundamental functions:

  1. Replication: must be able to replicate. In this sense, a DNA chain contains 2 strands of information that can be replicated in another 2 double chains.
  2. Expression: must be able to use the information to express hereditary characteristics or to encode proteins for the proper functioning of the organism.

DNA structure

DNA is a macromolecule with a double helix structure. The 2 strands that make up DNA go in opposite directions linked by their nitrogenous bases (Adenine, Guanine, Cytosine and Thymine). It is for this reason that it is often called the DNA structure as an inverted ladder.

What are the parts of DNA?

DNA is made up of deoxyribonucleotides, chains of nucleotides where each unit, in turn, is made up of 3 parts:

  1. a 5-carbon sugar molecule (deoxyribose for DNA and ribose for RNA),
  2. a phosphate group and,
  3. 4 nitrogenous bases (Adenine, Guanine, Cytosine and Thymine in DNA; Adenine, Guanine, Cytosine and Uracil for RNA).

Replication of DNA

Replication of DNA

DNA replication occurs before the cell divides and consists of obtaining identical copies of the fundamental cellular information for its transfer from one generation to another, thus constituting the basis of genetic inheritance.

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The coiled-up DNA (chromosome) is unraveled by the topoisonerase enzyme so that later, the helicase enzyme act by breaking the hydrogen bonds of the nitrogenous bases (Adenine, Guanine, Cytosine and Thymine) to separate the 2 strands.

Each strand has a directionality and each end is called 5′ and 3′ (five prime and three prime), and it is only possible to add nucleotides at the 3′ end, that is, the direction of elongation will always be from 5′ to 3 ‘.

Taking this into account, the nucleotides that will be paired with the information of a strand will be added by the DNA polymerase in the direction 5′ to 3′, where the hydrogenated bases Adenine always join with Thymine, Thymine always with Adenine, Guanine always with Cytosine and Cytosines always with Guanine.

DNA transcription

DNA structure, replication and transcription

The nucleotide sequence established on a DNA strand is transcribed into messenger RNA (mRNA). The transcription of DNA to the corresponding mRNA is similar to the process of DNA replication, in the sense of the association of nitrogenous bases.

In this way, the hydrogenated bases Adenine are united with the Uracil, the Thymine are always united with the Adenine, the Guanine always with the Cytosine and the Cytosines always with the Guanine.

Once the transcription is finished, the corresponding mRNA will transport the information to the ribosomes to begin the translation or protein synthesis.

DNA and RNA

DNA and RNA are nucleic acids and together they are responsible for maintaining, replicating, storing and transporting the genetic information that defines each living being. Thanks to this information, the unique characteristics of

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DNA stands for deoxyribonucleic acid, it has a deoxyribose sugar and its nitrogenous base is composed of: adenine, cytosine, guanine and thymine. It is characterized by having 2 strands coiled together to form a double helix.

In turn, RNA, that is, ribonucleic acid, contains ribose sugar, its nitrogenous base is made up of: adenine, cytosine, guanine and uracil. It is made up of a single strand.

However, they are both nucleic acids composed of sugars, a phosphate group, and a nitrogenous base.

DNA, chromosome and genes

DNA, chromosome and gene

DNA is the helical chain that contains the genetic information and for the synthesis of proteins of each organism. It is packaged in chromosomes at the time of meiosis or cell division, a preparatory phase so that the daughter cells each have an exact copy of the original DNA.

Instead, a gene is a segment of the DNA chain that defines or expresses a certain hereditary characteristic.

types of DNA

recombinant DNA

Recombinant or recombined DNA is a genetic recombination technology, that is, they identify genes (DNA segments that express certain characteristics of an organism), combine them and create new sequences. That is why this technology is also called DNA in vitro.

See also Genetics.

mitochondrial DNA

Mitochondrial DNA is a nucleic acid fragment in mitochondria. The mitochondrial genetic material is inherited exclusively from the mother. Mitochondrial DNA was discovered by Margit MK Nass and Sylvan Nass using the electron microscope and a marker sensitive to mitochondrial DNA.

Mitochondria are small organelles within eukaryotic cells, in order to produce energy for the cell to fulfill its functions. However, each mitochondria has its own genome and its own cellular DNA molecule.

See also Biomolecules.