6. Anatomía Bioquímica de la mitocondria
Qué es una mitocondria?
Estructura cilíndrica de 0.5 - 1 µm de diámetro.
Además del núcleo, la mitocondria contiene su
propio DNA y su propio mecanismo de replicación,
transcripción y traducción.
Cada mitocondria contiene de 2 a 10 copias de
DNA
7. Composición de las Membranas Mitocondriales
Membrana mitocondrial 40% lípidos: (fosfolípidos) PC, colesterol en baja
externa proporción
60% proteínas
The intermembrane space contains cytochrome c as
Espacio intermembrana a mobile electron carrier for the respiratory chain.
Release of cytochrome c into the cytosol initiates
caspase enzyme activation.
Membrana mitocondrial 20% lípidos: no colesterol; un 20% son cardiolípidos
interna 80% proteínas: CTE, enzimas complementarios,
transportadores específicos, ATP sintetasa
Enzimas del ciclo de Krebs y de la oxidación de AG grasos.
Matriz mitocondrial 2 a 10 moléculas de ADN circular, ARN y ribosomas (70S)
Enzimas involucrados en la síntesis de proteínas, iones,
nucleótidos, etc.
18. Summary of the flow of electrons and protons through the four
complexes of the respiratory chain
NADH dehydrogenase (complex I) spans the membrane and has a proton pumping mechanism
involving CoQ. The electrons go from CoQ to cytochrome b–c1 complex (complex III), and
electron transfer does NOT involve complex II.
Succinate dehydrogenase (complex II), glycerol 3-phosphate dehydrogenase, and ETF:Q
oxidoreductase (shown in blue) all transfer electrons to CoQ, but do not span the membrane
and do not have a proton pumping mechanism. As CoQ accepts protons from the matrix side,
it is converted to QH2. Electrons are transferred from complex III to complex IV
(cytochrome c oxidase) by cytochrome c, a small cytochrome in the intermembrane space
that has reversible binding sites on the b–c1 complex and cytochrome c oxidase.
