Hey what's up everyone welcome to my YouTube channel LifeScience with KMD. Today I'm going to explain about ribosomes. What is a ribosome? It is a ribonuclic acid enzyme or RNA with catalytic activity. What are the characteristic features of ribosome? It is an enzyme that utilizes RNA as a substrate or an RNA with enzymatic activity. An enzyme that catalyzes the association between the large and small ribosomal subunit. An enzyme that synthesizes RNA as a part of transcription process. An enzyme that synthesizes RNA primer during DNA replication. Investigators studying the origin of life have produced ribosomes in the laboratory that are capable of catalyzing their own synthesis under very specific condition such as an RNA polymerase ribosome. Some ribosomes may play an important role as a therapeutic agent as enzymes which target definite RNA sequence for cleavage as biosensors and for application in functional genomics and gene discovery. Classes of ribosomes catalytic RNAs are broadly grouped into two classes based on their size and reaction mechanism. Large and small ribosomes, the group 1 and group 2 introns RNAsp ribosomes are relatively large ribosomes which is having hundreds of nucleotides. The hammer-ed ribosomes, hairpin ribosomes, HDV ribosomes are substantially smaller less than 100 nucleotides. Now this is how ribosomes are classified. Small ribosomes which consist of 30 to 150 nucleotides. Example is hammer-ed, hairpin and HDV ribosomes whereas the large ribosomes consist of 100 to 3000 nucleotides. Example are introns group 1 and group 2 RNAsp. Groups of ribosomes, group 1 and group 2 introns-pricing ribosomes RNAsp, hammer-ed ribosomes, hairpin ribosomes and ribosomes. Group 1 introns-pricing, group 1 introns ribosomes constitute one of the main classes of ribosomes found in bacteria, lower eukaryotes and higher plants. Group 1 introns are also found inserted into genes of wide variety of bacteria of gram positive bacteria. However, their distribution in the phase of gram negative bacteria is mainly limited to T4, T1, T7 like bacteria of agers. Mechanism. The group 1 splicing reaction require a Gwana in residue co-factor. The 3 prime Vohetch group of Gwana is used as nucleophile. The 3 prime Vohetch group attacks the 5 prime phosphate of the introns and a new phosphodiester bond is formed. The 3 prime Vohetch of the exon that is displaced now act as a nucleophile in a similar reaction at the 3 prime end of the intron. So the introns is precisely excised and exons are joined together. The group 2 introns splicing, the group 2 introns have been found in bacteria and in mitochondria and chloroplast, genomes of fungi plants, protist and anilates worm. Mechanism. The 2 prime Vohetch of specific adenosine act as a nucleophile and attack the 5 prime splice site creating a branch in tron structure. The 3 prime Vohetch of the 5 prime exon attack the 3 prime splice site, ligating the exons and release the intron as a lyrid structure. Ribonucleus P, ribonucleoprotein is an essential TRNA processing enzyme found in all living organisms. Since it is a discovery almost 40 years ago, research on RNA sp has led to the discovery of catalytic property of RNA and of the only known naturally occurring RNA enzyme. Mechanism all RNA sp enzymes are ribonucleoprotein which consists of life in case of bacteria. It will be having one RNA then it will have one protein subunit. Whereas in case of eukaryotes, if one RNA is present there will be many protein subunits. Like for example in case of humans, it will having one RNA plus many like 11 protein subunits. In ribonucleus P, protein component is facilitates binding between RNAs and TRNA substrate. It requires a diver-lent metal ion like magnesium for its activity. Endo ribonucleus responsible for generating 5 prime end of metrotRNA molecule. Cleavage via nucleophilic attack on phosphodiester bond, leaving a 5 prime phosphate and 3 prime hydroxyl at the cleavage site. Hammereded ribosigns hammered ribosigns are tiny auto catalytic RNAs that cleave single-stranded RNA. They are found in nature as a part of certain virus like elements called pyroids which use rolling circle replication mechanism to reproduce their small circular RNA genome. Hammered ribosigns is so named because its secondary structure is similar to that of hammered but actually its tertiary structure is more like vyshaped. Auto catalytic cleavage occur via nucleophilic attack by the 2 prime hydroxyl of specific core nucleotide on its adjacent phosphodiester bond, producing 2 prime 3 prime cyclic phosphate and 5 prime hydroxyl terminate. Rolling circle replication initially produce a long strand of multiple copies of virusoid RNA. Each copy contains a hammered motive that catalyzed strand breakage between itself and the next copy in the transcript. Thus by virtue of hammered ribosign motive, the long strand breaks itself into many individual molecules. Hairpin ribosigns, the hairpin ribosign is an RNA motive that catalyze RNA processing reactions essential for replication of satellite RNA. In which it is embedded, these reactions are self processing that is a molecule rearrange its own structure. Both cleavage and end joining reactions are mediated by the ribosign motive. In contrast to the hammered and tetrahymenia ribosigns reaction, hairpin mediated cleavage and ligation proceed through a catalytic mechanism that does not require direct coordination of metal cations to phosphate and water oxygen. HDV ribosigns, the hepatitis delta virus, single-stranded circular RNA virus of approximately 1700 nubliotides. HDV infection requires the presence of hepatitis B-viron either coincident with HDV infection or as pre-existing infection. HDV is designated as a satellite virus of hepatitis B. HDV ribosigns are 85 nucleotides in length. Mutagenesis, experiment and chemical studies are shown that four helical region in many of which the nucleotides are located in helix 2 and its hairpin. The structural motive resemble neither the hammered nor the hairpin ribosigns. The hepatitis delta ribosign display high resistance to denaturing agent like urea and formamide. The self cleavaging activity of HDV RNA is enhanced in the presence of denaturants. Substrate recognition requires formation of the P1 stem. P1 ribosign is a circular ribosign and hybrid of both genomic and anti-genomic HDV ribosigns. Applications of ribosign as therapeutic agents. Treatment of disease and cancer to study gene function and gene therapy for disease. The property of ribosigns make them suitable in research of genetics and developmental biology. Thank you.