All organisms have nucleic acids . Maybe by this name are not so well known, but if I say “DNA” the thing possibly changes.
The genetic code is considered a universal language because it is used by all types of cells to store information about its functions and structures, which is why even viruses use it to survive.
In the article I will focus on clarifying the differences between DNA and RNAto better understand them.
What are DNA and RNA?
There are two types of nucleic acids: deoxyribonucleic acid, abbreviated as DNA or DNA .
DNA and RNA are two very different polymers, both in structure and function; however, they are both related and essential for the proper functioning of cells and bacteria .
Nucleic acids are made up of chains of chemical units called “nucleotides”. I will not go into many details about the chemical composition of these molecules, although there lie several of the differences between DNA and RNA.
The centerpiece of this structure is a pentose (a 5-carbon molecule), which in the case of RNA is a ribose, whereas in DNA it is a deoxyribose. Both give name to the respective nucleic acids. Deoxyribose gives more chemical stability than ribose , making the structure of DNA more secure.
Nucleotides are the keystone for nucleic acids, but they also play an important role as a free molecule in transferring energy in the metabolic processes of cells (for example in ATP).
Structures and types
There are several types of nucleotides and not all of them 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 form of life that is being talked about. In the case of human and eukaryotic animal cells , differences between DNA and RNA are observed in their structure, in addition to the presence of the nucleotides thymine and uracil mentioned above.
Differences between RNA and DNA
Below you can see the basic differences between these two types of nucleic acid.
Deoxyribonucleic acid is structured by two chains, so we say it is double-stranded. These chains draw the famous linear double helix , because they are interlaced between them as if they were a braid.
The binding of the two chains is produced by bonds between opposing nucleotides. This is not done randomly, but each nucleotide has affinity for one type and not for another: adenosine is always bound to a thymine, while guanine binds to cytosine.
In human cells, there is another type of DNA besides nuclear: mitochondrial DNA, a genetic material that is located inside the mitochondria, an organ responsible for cellular respiration.
Mitochondrial DNA is double-stranded but its form is circular rather than linear. This type of structure is typically observed in bacteria (prokaryotic cells), so it is thought that the origin of this organelle could be a bacterium that was attached to eukaryotic cells.
Ribonucleic acid in human cells is found in a linear fashion but is single-stranded, that is, it is formed by forming only one strand. In addition, by comparing their size, they are shorter than the strands of DNA.
However, there is a wide variety of RNA types, three of which are the most important, since they share the important function of protein synthesis:
- RNA messenger (mRNA) : acts as an intermediary between DNA and protein synthesis .
- Transfer RNA (tRNA) : transports the amino acids (units that form the proteins) in the protein synthesis. There are as many types of tRNA as amino acids used in proteins, specifically 20.
- Ribosomal RNA (rRNA) : together with proteins, part of the structural complex called ribosome, which is responsible for carrying out protein synthesis.
Duplication, transcription and translation
They are three very different processes and linked to the nucleic acids, but simple to understand.
Duplication only involves DNA. It occurs during cell division, when the genetic content is replicated. As the name implies, it is a duplication of the genetic material to form two cells with the same content.
Transcription, on the other hand, affects both nucleic acids. In general, DNA needs a mediator to be able to “extract” information from genes and synthesize proteins; for it makes use of RNA. Transcription is the process of passing the genetic code from DNA to RNA, with the structural changes it entails.
Finally, translation only acts on RNA. The gene already contains instructions on how to structure a particular protein and has been transcribed into RNA; now only need to pass from the nucleic acid to the protein .
The genetic code contains different combinations of nucleotides that have a meaning for protein synthesis. For example, the combination of the nucleotides adenine, uracil and guanine in the RNA always indicates that the amino acid methionine will be placed. Translation is the passage from nucleotides to amino acids, that is, what is translated is the genetic code