Ribonucleic acid (RNA) is a polymer involved in protein synthesis, gene replication, and deoxyribonucleic acid (DNA) replication. A polymer is a molecule made from linear chains, so RNA is linear chain made of ribonucleotides. Each ribonucleotide molecule consists of a nitrogen base with a phosphate group and ribose. Total RNA refers to RNA that extracted or isolated from cells or tissue for the purpose of genetic mapping. This type of complete RNA may be isolated from single cell organisms, animal tissue, plant tissue, yeast and fungus
Total RNA is extracted from cells and tissue during a process called RNA isolation. Cell disruption is the first and most important step in this process, and the cells can be disrupted by mechanical means, such as homogenization, or through the addition of enzymes. Enzymes chemically break down the coating or capsule of a cell so the total RNA may be isolated. During the isolation of total RNA, lipids, proteins and DNA are removed from the RNA so it is left in its purest form.
There are a number of differences between RNA and DNA, although the two nucleotides link together to form chains. RNA is a single chain polymer, while DNA is double-stranded. Additionally, DNA contains deoxyribose while RNA contains only ribose.
Although the most basic structure of RNA is a chain, RNA may have secondary and tertiary structures. Secondary structures are often helical and include hairpins, loops and knot-like shapes. Tertiary structures are the most complex and occur when distant nucleotides interact with one another. Scientists use these structures to understand and determine the functions of different RNA molecules.
Once a RNA molecule is synthesized during transcription, it must undergo processing before it is ready to perform its intended function. Processing involves altering segments or strands of specific nucleotides. RNA molecules with different functions have different names. For example, messenger RNA (mRNA) is named because it is responsible for transferring the genetic code from DNA to the ribosomes used during protein synthesis.
Protein synthesis, which is scientifically referred to as translation, requires two additional types of RNA in addition to mRNA. Translation RNA, or tRNA molecules, adapt nucleotides within mRNA to amino acids during translation. The RNA molecule that is responsible for linking ribosomes to growing protein chains is called rRNA. The three major types of RNA are required to be present for multiple RNA functions. Additionally, most of the less common types of RNA play a role in translation by performing essential functions in the nucleus and cytoplasm.