Class 11 NEET Biology Cell - The Unit of Life Questions Part 1

(d) : Ribosomes are minute cellular, nonmembranous particles having an average diameter of 23 mm (230 A°) In plant cells ribosomes were first of all observed by Robinson and Brown (1953) in bean roots. In animal cells, these were discovered by Palade (1955), hence are called Palade particles. Ribosomes form a part of fraction microsome, a term given by A. Claude (made of broken ER, ribosomes and Golgi bodies).