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Answer
Ribosome is an imporatnat cell organelle that play a key role in protein synthesis.
Discovery
Ribosome was discovered by Palade in 1955.
Structural composition
Chemically it is composed of an equal amount of rRNA and proteins, thats why it is also known as ribonucleoprotein.
Sub units of ribosomes
Ribosome is composed of two sub units one is smaller and the other one is larger. Both units are attached with each other with help of Mg atom.
Size of ribosome
In prokaryote the ribosome size is 70S, while in eukaryotes its size is 80S.
Polysome
When many ribosomes are attached to one mRNA strip it is called polysome or poly ribosome.
Role of ribosome
Ribosomes are the sites of synthesis of protein from amino acids.
Mechanism
mRNA which is the exact copy of DNA and formed in transcription come out from nucleus and attached to ribosomes. Now tRNA catch amino acids and come toward ribosome where its anti code match with genetic code of mRNA and then bonded to it. In this fashion a lot of amino acids are accumulated which make bonds with each others. Thus message present on mRNA in the form of genetic codes convert into protein through the process of transliteration.