Mitochondrion

This article describes an organelle, a cell component with its own distinctive structure and function. In eukaryotic cells, this is bounded by its own membrane, which is a lipid bilayer made of phospholipid.
Unless otherwise specified, information about this organelle is about its in situ occurrence in vivo, i.e., its occurrence in its usual location in living cells.

Mitochondrion (plural mitochondria) is an organelle found in eukaryotic cells whose primary function is to carry out aerobic respiration, i.e., convert energy from a relatively more hard-to-use form (pyruvates) to energy stored in the form of ATP.

Summary

Item	Value
Type of organisms whose cells contain mitochondria	eukaryotic cells only, both plant cells and animal cells
Type of cells within the organisms that contain mitochondria	All (?) cells
Number of mitochondria per cell	1 to 1000s, depending on the energy needs of the cell
Size	$0.5-10\mu m$ per mitochondrion. In some cells, it could take up to 1/5 of the cell volume
Location within cell	?
Structural components	outer mitochondrial membrane, intermembrane space, inner mitochondrial membrane, cristae, mitochondrial matrix
Chemical constituents	lots of proteins
Control of the entry and exit of materials	Membranes (hydrophilic/hydrophobic issues), the TIM/TOM complex
Function	aerobic respiration, i.e., ATP synthesis Control of cell cycle Cellular differentiation Cell growth Cell death
Evolutionary origin	endosymbiotic theory of mitochondrial origin -- the mitochondria are evolutionary descendants of endosymbionts (organisms living in the cell in a mutually beneficial relationship with their host)
Variation between individuals	Mitochondria have their own DNA which (in most eukaryotic organisms) is inherited from the mother. In addition, some of the behavior of the mitochondria is controlled by nuclear DNA.