Mitochondria diagram

Mitochondrion Definition The mitochondrion (plural mitochondria) is a membrane-bound organelle found in the cytoplasm of eukaryotic cells. It is the power house of the cell; it is responsible for cellular respiration and production of (most) ATP in the cell. Each cell can have from one to thousands of mitochondria. Mitochondria also contain extranuclear DNA that encodes a number of rRNAs, tRNAs, and proteins. The figure depicts the general structure of a typical animal cell. The organelles are labelled. Mitochondrion Origin The current theory as to the origin of eukaryotic cells is endosymbiosis. It is believed that mitochondria (and chloroplasts) began as prokaryotic organisms that were living within larger cells. It is likely that these prokaryotic organisms were engulfed by the larger cells, either as food or parasites. At some point the relationship became mutually beneficial and the mitochondria and chloroplasts became a permanent feature in the cells. They were enclosed in membranes and formed cellular machinery. Mitochondrion Structure Mitochondria are small membrane-bound organelles that are usually about 1 – 10 microns in length. They can be spherical or rod-shaped. The mitochondrion is enclosed by two membranes that separate it from the cytosol and the rest of the cell components. The membranes are lipid bilayers with proteins embedded within the layers. The inner membrane is folded to form cristae; this increases the surface area of the membrane and maximizes ce...