Describe the size and structure of eukaryotic ribosomes What

Describe the size and structure of eukaryotic ribosomes. What is the function of ribosomes. Why is it medically significant that eukaryotes have structurally different ribosomes than bacteria?

Solution

Size and structure of eukaryotic ribosomes:The ribosomes are tiny spherical organelles which are about ~3.2*10⁶Da and ~250-300 A or 25-30 nm.The ribosome is a cellular machine which is highly complex and it is made up of dozens of distinct proteins and ribosomal RNA.These ribosomal proteins and rRNA are arranged in to two distinct subunits of different sizes namely larer subunit and smaller subunit.In eukaryotes 80s ribosomes are present which are divided in to 60s and 40s subunits.The ribosomes are not surrounded by membrane.The 60s subunit has 5s RNA,23s RNA and 5.8s RNA and 40s RNA has 18s RNA and 33 proteins.The RNA is organised in various teritiary structures The catalytic activity of ribosomes is carried out by RNA and proteins

Function of ribosomes:The main function of ribosomes is protein synthesis.They assemble aminoacids to form specific proteins which are essential to carry out cellular activities.In the process of production of proteins the deoxyribonucleic acid produces mRNA by transcription process.And during translation the genetic information from mRNA is translated in to proteins.The sequence of the protein assembly is spcified in mRNA.The mRNA is synthesized in the nucleus and transported to cytoplasm for further process of protein synthesis.In the cytoplasm the two subunits are bound around the polymers of mRNA and then the proteins are synthesized with the help of tRNA.The proteins produced by the bound ribosomes are transported outside the cell.

       The eukaryotic ribosomes have more proteins than RNA when compared to prokaryotic ribosomes which have more RNA than proteins.Prokaryotic ribosomes are vulnerable to some antibiotics where as eukaryotic ribosomes are not vulnerable.So, these are medically significant than bacteria.Many of the antibiotics are specially inhibit the ribosomal activity in the disease causing bacteria with out affecting ribosome function in host cells. These antibiotics work by binding to a protein in bacterial ribosome and inhibit their translation.