Elaborate on structure, type and functions of Ribosomes.

Ribosomes are complex molecular machines found within all living cells that serve as the site of biological protein synthesis (translation). They link amino acids together in the order specified by messenger RNA (mRNA) molecules. Ribosomes consist of two major components: the small ribosomal subunit, which reads the RNA, and the large subunit, which joins amino acids to form a polypeptide chain.

Structure of Ribosomes: Ribosomes are made from complexes of RNAs and proteins. The ribosomes found in prokaryotes, eukaryotes, and mitochondria are quite similar in structure. They are composed of two subunits of unequal size, termed the large and small subunit. Each subunit exists separately in the cytoplasm, but the two join together on the mRNA molecule during protein synthesis (translation).

Types of Ribosomes: There are two types of ribosomes, free ribosomes and bound ribosomes. Free ribosomes are suspended in the cytosol, while bound ribosomes are attached to the endoplasmic reticulum. The type of protein produced by a ribosome is determined by the mRNA it reads. Free ribosomes usually make proteins that will function in the cytosol, while bound ribosomes make proteins that are exported or included in cell membranes.

Functions of Ribosomes: The primary function of ribosomes is to synthesize proteins. Ribosomes accomplish this through a process called translation, where they decode the information in mRNA and use it to create a chain of amino acids. This chain then folds into a three-dimensional shape to form a protein. Ribosomes can also be found within the mitochondria, where they synthesize proteins needed for the mitochondria to function.