Living cells generally are divided into two major classes— eukaryotes and prokaryotes. The cells of higher animals and plants are eukaryotes, as are the single-celled organisms fungi, protozoa, and most algae. Prokaryotes include cyanobacteria (blue-green algae), bacteria, and rickettsiae. Prokaryotes traditionally were studied as core subjects of molecular biology. Current emphasis is on the eukaryotic cell; much of its structure and function has no counterpart in bacterial cells.
Eukaryotes (eu = good; karyon = nucleus) are larger and have more extensive intracellular anatomy and organization than do prokaryotes. Eukaryotic cells have a characteristic set of membrane-bound intracellular compartments, called organelles, that includes a well-defined nucleus. Prokaryotes contain no organelles, and their nuclear material is not encased by a nuclear membrane. Prokaryotic cells are characterized by lack of a distinct nucleus.
Besides having structural differences, prokaryotic and eukaryotic cells differ in chemical composition and biochemical activity. The nuclei of prokaryotic cells carry genetic information in a single circular chromosome, and they lack a class of proteins called histones, which in eukaryotic cells bind with deoxyribonucleic acid (DNA) and are involved in the supercoiling of DNA. We now understand that the loops and coiling of DNA are important for many diseases. Eukaryotic cells have several chromosomes. Protein production, or synthesis, in the two classes of cells also differs because of major structural differences in ribonucleic acid (RNA)–protein complexes.Other distinctions include differences in mechanisms of transport across the outer cellular membrane and differences in enzyme content.
McCance, K. L., & Huether, S. E. (2015). Pathophysiology: The biologic basis for disease in adults and children. St. Louis: Mosby.
Are you sure you want to delete this post?