Oxidative Phosphorylation Flashcards Preview

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Flashcards in Oxidative Phosphorylation Deck (13)
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describe the P/O ratio

  • P/O ratio = ratio of ATP formed per O atom reduced
  • P/O ratio for NADH = 3 ATP:1 NADH oxidized by ETC
  • P/O ratio for FADH2 = 2 ATP:1 NADH oxidized by ETC
    • less ATP because it bypasses complex I of the ETC


name inhibitors of the ETC


ETC will be active when ___ > ____ and ____ > _____

ETC will be active when [ADP] > [ATP] and [NADH] > [NAD+]


describe mt DNA and mutations

  • mtDNA encodes 37 genes
  • phenotypes are highly pleiotropic: one mutation can cause multiple phenotypes


mitochondrial disorders are characterized by "____ ___ ___" which can be stained with ______

mitochondrial disorders are characterized by "ragged red fibers" which can be stained with Gomoritrichrome


mitochondrial proliferation in muscle fibers also seen by staining for ______ ______

mitochondrial proliferation in muscle fibers also seen by staining for succinate dehydrogenase (complex II)


describe Leber's hereditary optic neuropathy

  • defect in NADH dehydrogenase (complex 1 of ETC)
  • characterized by degeneration of the retinal ganglion cells


describe deafness induced by aminoglycoside antibiotics

  • mutation in mitochondrial rRNA may cause predisposition to aminoglycoside toxicity causing deafness


describe Kearns-Sayer

  • deletion within mt DNA
    • most common region is 4997 bp
  • affects system with higher energy requirements 
    • paralysis of eye muscles and degeneration of retina
    • cardiac problems
    • ataxia


describe MELAS

  • mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes
  • most common mt disease
  • oxdiative phosphorylation defect caused by a mutation in mt tRNA
  • causes excess pyruvate to be reduced to lactic acid which accumulates in blood and other fluids


describe MERRF

  • myoclonic epilepsy; ragged red fibers
  • most common mutation in mt tRNA gene


what are potential treatment for patients with mt disorders?

  • small frequent meals 
  • CoQ10
  • vit. C
  • high fat diet
  • carnitine


describe artificial reproductive technology with mt disorders

  1. healthy nucleus is extracted from mother's defective egg
  2. nucleus removed from healthy donor egg and replaced with mother's nucleus (so donor's mtDNA still there)
  3. egg carrying genetic material of two women fertilized by male sperm and implanted