<prompt> Size of fibrillary proteins in amyloidosis:0-5 nm7.5-10 nm12-17 nm18-20 nm  <response>: Ans. b 7.5-10 nm. Robbin Pathologic Basis of Diseases 5th231PHYSICAL NATURE OF AMYLOID By electron microscopy, amyloid is seen made up largely of non-branching fibrils of indefinite length and a diameter of approximately 7.5 to 10 nm. X-ray crystallography and infrared spectroscopy demonstrate a characteristic cross 3-pleated sheet conformation. Chemical nature:- AL amyloid light chain- AA amyloid associated- AB Alzheimers disease 