Definition of "ultrastructure" [ultrastructure]

• The detailed structure of a biological specimen, such as a cell, tissue, or organ, that can be observed only by electron microscopy. Also called fine structure. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "He has published widely on the ultrastructure and molecular evolution of algae and advised scores of graduate students during his distinguished scientific career."
• "Garcia-Segura, LM, et al. Gonadal hormone regulation of fibrillary acidic protein immunoreactivity and glial ultrastructure in the rat neuroendocrine hypothalamus."
• "In addition to her expertise in the molecular structure of DNA, Rosalind Franklin was an expert in two other areas: the effects of heat on the microstructure of coal which included the changes that occurred during the conversion of some coals to graphite; and the quantitative analysis of the ultrastructure of the experimentally important RNA (Ribonucleic Acid) virus and TMV (Tobacco Mosaic Virus)."