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Facts about Mitochondria for Kids

The mitochondrion (plural mitochondria) is a double membrane-bound organelle found in most eukaryotic cells. These structures are described as “the powerhouse of the cell” because they generate most of the cell’s supply of adenosine triphosphate (ATP), used as a source of chemical energy.

  • In addition to supplying cellular energy, mitochondria are involved in other tasks, such as signaling, cellular differentiation, and cell death, as well as maintaining control of the cell cycle and cell growth.
  • These compartments or regions include the outer membrane, the intermembrane space, the inner membrane, and the cristae and matrix.
  • In humans, 615 distinct types of protein have been identified from cardiac mitochondria, whereas in rats, 940 proteins have been reported.
  • In 1939, experiments using minced muscle cells demonstrated that cellular respiration using one oxygen atom can form two adenosine triphosphate (ATP) molecules, and, in 1941, the concept of the phosphate bonds of ATP being a form of energy in cellular metabolism was developed by Fritz Albert Lipmann.
  • Disruption of the outer membrane permits proteins in the intermembrane space to leak into the cytosol, leading to certain cell death.
  • The mitochondrial outer membrane can associate with the endoplasmic reticulum (ER) membrane, in a structure called MAM.
  • Not only has the MAM provided insight into the mechanistic basis underlying such physiological processes as intrinsic apoptosis and the propagation of calcium signaling, but it also favors a more refined view of the mitochondria.
  • Sufficient intraorganelle Ca signaling is required to stimulate metabolism by activating dehydrogenase enzymes critical to flux through the citric acidcycle.
  • Mitochondria play a central role in many metabolic tasks, such as: Signaling through mitochondrial reactive oxygen species Regulation of the membrane potential Apoptosis-programmed cell death Calcium signaling Regulation of cellular metabolism Certain heme synthesis reactions Steroid synthesis.
  • The endosymbiotic hypothesis suggests that mitochondria were originally prokaryotic cells, capable of implementing oxidative mechanisms that were not possible for eukaryotic cells; they became endosymbionts living inside the eukaryote.
  • Damage and subsequent dysfunction in mitochondria is an important factor in a range of human diseases due to their influence in cell metabolism.