11.A Mitochondria (origin,structure and function)

Types - according to the type of internal membrane folding

1 Mitochondria with cristae 2 Mitochondria with tubules (tubular type)

Mitochondria are the organelles necessary for the conversion of chemical energy from nutrients to the types of energy that can be utilized by the cell.

chemical nutrients

Mitochondrial DNA filament / mitochondrial chromosome - circular double stranded DNA molecule - usually not bound to proteins (histones)

circular (histones)

Internal mitochondrial membrane membrane membrane folding / invaginations, creating cristae or tubules

cristae tubules

After fertilization, all sperm mitochondria dissipate (they are probably actively destroyed by oocyte lysosomes). Hence, all the mitochondria in the embryo (even mitochondrial DNA) originate exclusively from the mother.

dissipate mother.

Mitochondria are the energy centers of cells.

energy

Endosymbiotic theory (symbiogenesis) mitochondria probably evolved from eubacteria, which lived in a symbiotic relationship within the cytoplasm of primitive eukaryotic cells

eubacteria, eukaryotic

Endosymbiotic theory (symbiogenesis) 1 External mitochondrial membrane

has a composition similar to cell membrane

There are several hundred to tens of thousands of mitochondria in one cell (depending on metabolic activity).

hundred tens of thousands

3 Mitochondria have their own genome

in the form of a circular molecule similar cimilar to te prokaryotic DNA

Mitochondrial matrix semi-liquid mass delimited by the internal mitochondrial membrane contains enzymes active in the Krebs cycle and beta-oxidation of fatty acids

internal Krebs cycle beta-oxidation

2 Mitochondria with tubules (tubular type) have longitudinally oriented tubular projections of inner membrane typical for cells producing steroid hormones, in adrenal cortex cells, in the interstitial endcrine cells of Leydig of testis

longitudinally tubular steroid

1 Mitochondria with cristae - the most common type of mitochondrial - cristae are usually directed perpendicularl to the long axis of the mitochondria

most common perpendicularl

Intermembranous space between the outer and the inner membrane

outer inner

External mitochondrial membrane smooth, highly permeable to ions and water numerous porins, transport canals lipid-protein ratio of 1:1

smooth, ions water porins, 1:1

Mitochondria are covered with two membranes and have a variable shape (rod, fila- ment, oval to spherical).

two (rod, filament,

Cellular respiration produces energy-rich ATP molecules using en- ergy generated by the systematic decomposition of nutrients (glucose, fatty acids, etc.).

Cellular respiration ATP

4 Ribosomes of mitochondria are of prokaryotic type

prokaryotic

Mitochondria contain their own DNA and ribosomes, making them semi-autonomous organelles (the formation of their proteins is partly indepen- dent of the nucleus).

DNA ribosomes, proteins