Differences between DNA and RNA

All organisms have nucleic acids. Maybe under that name they are not that well known, but if I say “DNA” that will probably change.

The genetic code is considered a universal language because it is used by all types of cells to store information about their functions and structures, which is why even viruses use it to survive.

In the article I will focus on clarify the differences between DNA and RNA to better understand them.

    What are DNA and RNA?

    There are two types of nucleic acids: deoxyribonucleic acid, abbreviated as DNA or DNA in its English nomenclature, and ribonucleic acid (RNA or RNA). These elements are used to make copies of cells, which will build the tissues and organs of living things in some cases, and single-celled life forms in others.

    DNA and RNA are two very different polymers, both in terms of structure and function; however, they are both linked and essential to the right how cells and bacteria work. After all, although its “raw material” is different, its function is similar.

      nucleotides

      Nucleic acids are formed by chains of chemical units called “nucleotides”. To put it another way, they are like the bricks that make up the genotype of different life forms. I won’t go into details about the chemical makeup of these molecules, although several of the differences between DNA and RNA lie there.

      The centerpiece of this structure is a pentose (a 5-carbon molecule), which in the case of RNA is ribose, while in DNA it is deoxyribose. Both give names to their respective nucleic acids. Deoxyribose gives more chemical stability than ribose, Make DNA structure more secure.

      Nucleotides are the centerpiece of nucleic acids, but they also play an important role as a free molecule in the energy transfer in metabolic processes cells (eg in ATP).

        Structures and types

        There are several types of nucleotides and not all are found in both nucleic acids: adenosine, guanine, cytosine, thymine and uracil. The first three are shared in the two nucleic acids. Thymine is only in DNA, while uracil is its counterpart in RNA.

        The configuration of nucleic acids is different depending on the lifestyle we are talking about. In the case of eukaryotic animal cells like humans differences between DNA and RNA are observed in their structure, in addition to the different presence of the aforementioned thymine and uracil nucleotides.

        The differences between RNA and DNA

        Below you can see the basic differences between these two types of nucleic acid.

        1. DNA

        Deoxyribonucleic acid is structured by two chains, so we say it is double stranded. these the chains form the famous double helix linear, because they intertwine as if it were a braid. In turn, strands of DNA are coiled onto chromosomes, entities that remain clustered inside cells.

        The binding of two strands of DNA occurs through bonds between opposing nucleotides. This does not happen at random, but each nucleotide has an affinity for one type and not for another: adenosine always binds to a thymine, while guanine binds to cytosine.

        In human cells, there is another type of DNA besides nuclear: Mitochondrial DNA, genetic material which is located inside the mitochondria, the organelle responsible for cellular respiration.

        Mitochondrial DNA is double stranded, but its shape is circular rather than linear. This type of structure is typically seen in bacteria (prokaryotic cells), so it is believed that the origin of this organelle may have been bacteria that joined cells from eukaryotes.

        2. RNA

        Ribonucleic acid in human cells is found in a linear fashion but it is single-stranded, that is, it is configured to form a single chain. Moreover, by comparing their size, their strands are shorter than DNA strands.

        However, there are a wide variety of types of RNA, including three of the most important, as they share the important function of protein synthesis:

        • Messenger RNA (mRNA): Acts as an intermediary between DNA and protein synthesis.
        • RNA transfer (tRNA): Carries amino acids (units that make up proteins) in protein synthesis. There are as many types of tRNA as there are amino acids used in proteins, especially 20.
        • Ribosomal RNA (rRNA): They are part, along with proteins, of the structural complex called the ribosome, which is responsible for carrying out protein synthesis.

        Duplication, transcription and translation

        Those who name this section are three very different processes related to nucleic acids, but simple to understand.

        Duplication only involves DNA. It occurs during cell division, when genetic content is replicated. As the name suggests, it is a duplication of genetic material to form two cells with the same content. It is as if nature made copies of the material which will then be used as a blueprint showing how an item is to be constructed.

        Transcription, on the other hand, affects both nucleic acids. In general, DNA needs a mediator in order to be able to “extract” genetic information and synthesize proteins; that’s why it uses RNA. Transcription is the process of transmitting the genetic code from DNA to RNA, with the structural changes involved.

        Finally, translation acts only on RNA. The gene already contains instructions on how to structure a particular protein and has been transcribed into RNA; now only missing switch from nucleic acid to protein.

        The genetic code contains different combinations of nucleotides which have significance for protein synthesis. For example, the combination of the nucleotides adenine, uracil and guanine in RNA always indicates that the amino acid methionine will be placed. Translation is the transition from nucleotides to amino acids, i.e. what is translated is the genetic code.

          Bibliographical references:

          • Alquist, P. (2002). RNA-dependent silent RNA polymerases, viruses and RNAs. Science 296 (5571): 1270 – 1273.
          • Dahm, R. (2005). Friedrich Miescher and the discovery of DNA. Developmental Biology 278 (2): 274 – 288.
          • Dame, RT (2005). The role of nucleoid-associated proteins in the organization and compaction of bacterial chromatin. Mol. Microbiol. 56 (4): 858-70.
          • Hüttenhofer, A., Schattner, P., Polacek, N. (2005). Non-coding RNAs: Hope or Hype ?. Trends Rider 21 (5): 289 – 297.
          • Mandelkern, M., Elias, J., Eden, D., Crothers, D. (1981). The dimensions of DNA in solution. J Mol Biol. 152 (1): 153-161.
          • Tuteja, N., Tuteja, R. (2004). Unravel DNA helicases. Reason, structure, mechanism and function. Eur J Biochem 271 (10): 1849-1863.

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