Mitochondrial Energy Pathways Flashcards
(23 cards)
How many mitochondria are in a healthy cell?
varies from 200 to 10000
How many mitochondria are in a liver cell?
1000
How many mitochondria are in an aged cell?
as few as 10 - killed off by ROS caused by electrons leaked from the electron transport chain
Where did mitochondria come from in evolution?
an endosymbiotic relationship with bacteria
What biochemistry pathways are carried on in mitochondria?
acetyl CoA production, ketone body synthesis, Krebs cycle, oxidative phosphorylation
What is the pathological sign of mitochondrial diseases?
ragged red fibres in a muscle biopsy
How are mitochondrial diseases inherited?
maternally
Are all mitochondrial diseases due to mutations in mitochondrial DNA?
no - can also be from nuclear DNA
What are the products of fatty acid metabolism?
ketone bodies - including beta hydroxybutyrate
How does pyruvate get into the mitochondrial matrix?
via a transporter - either a symporter with H+ or an antiport with hydroxyl
What are the products of the citric acid cycle?
3 NADH, 1 FADH2 and 1 ATP/GTP
What are the anabolic fates of the citric acid cycle?
fatty acids, sterols, purines, porphyrins, heme, amino acids
What is involved in the electron transport chain?
electron flow through 4 respiratory complexes on the mitochondrial membrane
What is the result of the electron transport chain?
10 H+ ions which drive ATP synthesis through ATP synthase
What are uncouplers of oxidative phosphorylation?
they allow H+ ions to leak through the membrane without ATP production
Where does uncoupling of oxidative phosphorylation occur and what is generated instead?
in brown fat - generates heat
What enzyme is involved in complex II of the electron transport chain?
succinate dehydrogenase
Which mitochondrial complex in the electron transport chain is not encoded by mitochondrial DNA?
complex II
What is the malate aspartate shuffle?
a shuttle which transfers the reducing power of NADH from cytosol to mitochondria for oxidative phosphorylation
What is the glyercol-3-phosphate shuffle?
a shuttle which transfers the reducing power of NADH from cytosol to mitochondria for oxidative phosphorylation in the muscle - but it costs energy
What is the ATP yield of one glucose molecule?
32
What are the precursors for Acetyl CoA production?
pyruvate, fatty acids, amino acids
What is the precursors for ketone body synthesis?
Acetyl CoA
