Ribosomes are the particles present in the cells in large numbers and mainly serve as a site for protein synthesis. They are present as free particles in both prokaryotic and eukaryotic cells and also attached to the membrane of the endoplasmic reticulum in the case of eukaryotic cells. The Discovery of ribosomes was in the year 1955 by a Romanian-American cell biologist George E. Palade, during his discovery he found that ribosomes are associated with the endoplasmic reticulum in eukaryotic cells.
Along with protein synthesis, they also function by binding to a messenger ribonucleic acid (mRNA) and decoding the information carried by the nucleotide sequence of the mRNA. The transfer RNA’s having amino acids, enters into the ribosomes at the acceptor site. Once after getting added up, it further adds amino acid to the growing protein chain on tRNA.
1. Explain the Functioning of Ribosomes?
Ans. Some of the important functions of ribosomes are discussed below:
1. Their major function is assembling amino acids for the formation of protein which is essential to carry out cellular functions.
2. Synthesis of mRNA from DNA by the process of DNA transcription.
3. Synthesis of mRNA in the nucleus and its transportation to the cytoplasm is done by ribosomes for the synthesis of protein.
4. Synthesis of protein with the help of tRNA, as the ribosomal subunits in the cytoplasm, are bound around mRNA polymers.
5. Synthesis of protein occurs in the cytoplasm and is utilised in the cytoplasm itself whereas the protein which is synthesised by bound ribosomes are exported outside.
2. Explain the Composition of Ribosomes?
Ans. Ribosomes are composed of two subunits, they are:
A. The small ribosomal subunits- these subunits read the mRNA.
B. the large ribosomal subunits- these subunits mainly help in the formation of polypeptide chains of amino acids.