OLUWATOSIN OLADOKUN 0308

TABLE OF CONTENTS  WHAT IS MITOCHONDRIA?  STRUCTURE OF MITOCHONDRION  THE OUTER MEMBRANE  THE INTERMEMBRANE SPACE  THE INNER MEMBRANE SPACE  CRISTAE  MATRIX  FUNCTIONS OF MITOCHONDRIA  INHERITANCE AND DISORDERS  RELATED VIDEOS  REFERENCES

WHAT IS MITOCHONDRIA? The mitochondrion is a membrane bound organelle found in the cytoplasm of most eukaryotic cells. The word ‘mitochondrion’ comes from the Greek ‘mitos’ meaning ‘thread’ and ‘chondrion’ meaning ‘granule’.

A COLORED TRANSMISSION ELECTRON MICROGRAPH

STRUCTURE OF A MICHONDRION A mitochondrion contains outer and inner membranes composed of phospholipids bilayers and proteins. There are five distinct parts to a mitochondrion because it has a double-membraned organization;  The outer mitochondrial membrane  The intermembrane space  The inner mitochondrial membrane  The cristae space  The matrix

THE OUTER MEMBRANE  It is permeable to small molecules.  It can associate with the endoplasmic reticulum important for calcium signalling and the transfer of lipids.  It has a protein to phospholipid ratio of 1:1.  It contains large numbers of integral proteins called porins.

INTERMEMBRANE SPACE The space between the outer and inner membranes. It is also known as perimitochondrial space’ Plays a role in oxidative phosphorylation.

I NNER MEMBRANE SPACE In contrast to the outer membrane, it is less permeable, allowing only very small molecules to cross into the gel- like matrix that makes up the organelle’s central mass. Contains proteins of the electron transport chain and is the barrier allowing the formation of a proton pump for ATP production.

CRISTAE  Folded lamellae of the mitochondria a.k.a invaginations of inner membrane.  Increase to a great extent, the total surface area of the inner membrane.  Allow faster rate of diffusion of components from matrix to inner membrane.  Cells with a greater demand for ATP, such as myocytes contain more folds.

MATRIX Contains enzymes that are responsible for the citric acid cycle reactions. Contains dissolved oxygen, water, carbon dioxide, recyclable intermediates that serve as energy shuttles. Matrix components can diffuse to inner membrane complexes and transport proteins within a short period of time. Citric acid cycle occurs here.

FUNCTIONS

INHERITANCE AND DISORDERS  Only the maternal mitochondria are inherited.  This is because the paternal mitochondria are contained inside the neck of the sperm which is does not penetrate into the secondary oocyte at fertilization.  Therefore, disorders arise when only the maternal mitochondria is affected.

MUTATION-RELATED DISORDERS  Kearns-syndrome  MELAS syndrome  Leber’s hereditary optic neuropathy (LHON)  Pearson’s syndrome

ENVIRONMENTALLY- INFLUENCED MITOCHONDRIAL DISORDERS

MITOCHONDRIAL FACTS Did you know that: The mitochondrion is one organelle that has its own independent genome? Mitochondria divide by binary fission, similar to bacterial cell division? Mitochondrial DNA was discovered in the 1960s by electron microscopy and biochemical assays?

RELATED VIDEOS A A multimedia.mcb.harvard.edu/anim_mit ichondria.html education-portal.com/…/mitochondria- structure-cristae-… prep/mcat/…/v/electron-transport-chain

REFERENCES ochondria/mitotheory.html /mitochondrion ons/electron%20micrographs.html chondria