What role do ribosomes play in cells?

Ribosomes are cellular structures that synthesise proteins by translating messenger RNA (mRNA).

Ribosomes are essential components of all cells, both prokaryotic and eukaryotic. They are the sites of protein synthesis, a process that is fundamental to the survival and functioning of cells. This process, also known as translation, involves the decoding of genetic information stored in the form of messenger RNA (mRNA) into a sequence of amino acids that make up a protein.

Ribosomes are composed of two subunits, a larger one and a smaller one. These subunits are made up of ribosomal RNA (rRNA) and proteins. The smaller subunit binds to the mRNA, while the larger subunit binds to transfer RNA (tRNA), which carries the amino acids. The ribosome moves along the mRNA, reading its sequence three nucleotides at a time (a codon), and matching each codon with the appropriate amino acid carried by the tRNA. This results in the formation of a polypeptide chain, which eventually folds into a functional protein.

The number of ribosomes in a cell can vary greatly, depending on the cell's protein synthesis needs. For instance, cells that are very active in protein synthesis, such as those in the liver, have a large number of ribosomes. Ribosomes can be found either floating freely in the cytoplasm or attached to the endoplasmic reticulum, a network of membranes within the cell. The latter are involved in the synthesis of proteins destined for insertion into membranes or for export from the cell.

In summary, ribosomes play a crucial role in cells by synthesising proteins, which are necessary for the structure, function, and regulation of the body's tissues and organs. Without ribosomes, cells would not be able to produce proteins, and life as we know it would not be possible.