Notability Notes
Notability Notes
Notability Notes
• Mitochondria use aerobic respiration to generate most of the cell's supply of adenosine
triphosphate, which is subsequently used throughout the cell as a source of chemical energy
• The number of mitochondria in a cell can vary widely by organism, tissue, and cell type.
• A mature red blood cell has no mitochondria,[17] whereas a liver cell can have more than 2000.
• The mitochondrion is composed of compartments that carry out specialized functions. These
compartments or regions include the outer membrane, intermembrane space, inner membrane,
cristae, and matrix.
Structure of Mitochondria
I
Outer Mitochondrial Membrane
1. resembles more with the plasma membrane in structure and chemical composition.
2. Porins in the outer membrane allow small molecules to be exchanged between the cytoplasm
and the intermembrane space.
Intermembrane Space
It is the space between the outer and inner membrane of the mitochondria, it has the same
composition as that of the cell’s cytoplasm.
There is a difference in the protein content in the intermembrane space.
mitochondrial matrix
1. which is the liquid (colloidal) area encircled by the inner membrane, contains the soluble
enzymes of the Krebs cycle which completely oxidize the acetyl-CoA to produce CO2, H2O and
hydrogen ions. Hydrogen ions reduce the molecules of NAD and FAD, both of which pass on
hydrogen ions to respiratory or electron transport chain where oxidative phosphorylation takes
place to generate energy-rich ATP moleculesal Matrix
2. Mitochondria also contain in their matrix single or double circular and double-stranded DNA
molecules called mt DNA and also the 55S ribosomes, called mitoribosomes. Since mitochondria
can synthesize 10 percent of their proteins in their own protein-synthetic machinery, they are
considered as semi-autonomous organelles.
Functions of Mitochondria
1. The most important function of mitochondria is to produce energy. Mitochondria produce the
molecule adenosine triphosphate (ATP), one of the cell’s energy currencies that provide the
energy to drive a host of cellular reactions and mechanisms.
2. The simpler molecules of nutrition are sent to the mitochondria to be processed and to produce
charged molecules. These charged molecules combine with oxygen and produce ATP
molecules.. This process is known as oxidative phosphorylation.
3. Mitochondria may also produce heat (brown fat), and accumulate iron-containing pigments
(Heme ferritin), ions of Ca2+ and HPO42– (or phosphate; e.g., osteoblasts of bones or yolk
proteins).
4. Mitochondria help the cells to maintain the proper concentration of calcium ions within the
compartments of the cell.
5. The mitochondria also help in building certain parts of blood and hormones like testosterone
and estrogen.
6. The liver cell’s mitochondria have enzymes that detoxify ammonia.
7. The mitochondria also play an important role in the process of apoptosis or programmed cell
death.
8. Abnormal death of cells due to the dysfunction of mitochondria can affect the function of an
organ.