Table of Contents
Introduction of Mitochondria
Mitochondria are organelles found in most eukaryotic cells such as animals, plants and fungi. Mitochondria have a double-membrane structure and generate adenosine triphosphate through aerobic respiration, which is used as a chemical energy source throughout the cell.
Brief history
Mitochodrion was first observed in 1857 by Kolliker in muscles. He named them Sarcosomes altmann in 1894. It was recognised as independent organelles.
Benda 1897 called organelles mitochondria(Greek, mitro=tread+=granules).
Hans krebs(1937) first described the citric acid cycle and received nobel Prize for the discovery hogeboom and co- workers (1948) first demonstrated the cellular respiration occurs in mitochondria.
Origin of Mitochondria
According to the endosymbiont hypothesis eukeryotic cells evolved without mitochondria and chloroplasts. Similarly the mitochondria and chloroplasts evolved directly directly from prokaryotes.
Biogenesis of mitochondria (by division)
The life span of mitochondria is 5 to 10 days. It means that mitochondria must be produced to replace the old one.
New mitochondria arise by growth and division of existing mitochondria. election micrograph suggest that it’s division begins by an inward furrowing of the inner mitochondrial membrane.
Morphology
1. Size and shape
In most cells, mitochondria are spherical or slightly elongated (rod like). It measure 0.2 to 1.0 micrometer in diameter and 1 to 4 micrometer in length.
Mitochondria change their shape according to the physiological conditions of the cells.
They may be club, racket, vesicular Or rounded in shape. They may fuse together and divide also.
2. Number of position
A few alage and some protozoa contain a single mitochondrion. Most cells, however contain several hundred mitochondria.
A few large cells, like eggs of animal and the giant amoeba contain several hundred thousand mitochondria.
Chemical Composition Membranes
Chemically the outer and inner mitochondrial membrane differ from each other.
The outer membrane contains 3 to 4 times more Phospholipids than the inner membrane.
The inner membrane is much richer in proteins than the outer membrane.
What Does the Mitochondria Do?
Mitochodri (singular, mitochondrion), are found in all eukaryotic cells except red blood cells of higher animals.
It is called the power house of the cell because it synthesizes and provides chemical energy (ATP) to the cell.
Ultrastructure
Mitochodria are large particles and can be seen by light microscope. Electron microscopic studies show that mitochondrion contains two membrane and two chambers.
1. Outer Membrane
It is continuous and smooth and surrounds the mitochondrion. It is 60Å in thickness.
2. Inner Membrane
inside the outer membrane there is a second membrane, the inner membrane. It is also 60Å in thickness.
3.The Intermembrane Space
The space between the outer and inner membranes is called the Intermembrane space.
4. The matrix space
The inner membrane surrounds a large chamber called the matrix space. The cristae project in this chamber. The chamber is called with gel like matrix.
5. F1 particle
The matrix side of the membrane of the cristae remain covered with spherical particles 90Å in diameter.
Functions of Mitochondria
Mitochondria are the power houses of the cells. They supply 95℅ of the energy required by the cell.
Mitochodria’s primary function is to produce energy through the process of Oxidative phosporylation it is responsible for regulating the metabolic activity of the cell.