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Oxidative phosphorylation NADH transport Oxidative phosphorylation.

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Presentation on theme: "Oxidative phosphorylation NADH transport Oxidative phosphorylation."— Presentation transcript:

1 Oxidative phosphorylation NADH transport Oxidative phosphorylation

2 p691 Only those with specific transporters can pass All pathways related to fuel oxidation except glycolysis N side

3 Oxidative phosphorylation Converting the energy from electrons (from NADH and FADH 2 ) to ATP

4 1. NAD + 2. FAD 3. Ubiquinone 4. Cytochromes 5. Iron-sulfur proteins Five electron carrying molecules

5 Ubiquinone (coenzyme Q; Q; Q 10 ) Ubiquinone Plastoquinone (plant chloroplast) Menaquinone (bacteria) p693

6 p694 cytochromes

7 p695 Iron-sulfur proteins

8 Method for determining the sequence of electron carriers p696 ABCDEF ABCDEF ABCDEF

9 p698

10 Chemical uncouplers Chemicals like DNP and FCCP are weak acid with hydrophobic properties that permit them to diffuse readily across mitochondrial membranes. After entering the matrix in the protonated form, they can release a proton, thus disspating the proton gradient. p707

11 Ionophores Valinomycin (an ionophore) allows inorganic ions to pass easily through membranes. This will uncouple electron transfer from oxidative phosphorylation. p406

12 p696

13 p698 Complex I

14 p697 Complex I & II

15 p700 Complex III

16 p702 Complex IV

17 H+ III Cyt c H+ I II IV NADH NAD+ e e Q e e H+ O H2O NADH FADH2 e FAD e H+ O FADH2 Mitochondrial inner membrane Mitochondrial matrix Mitochondrial intermembrane space

18 p703

19 p675

20 p711 Mitochondrial ATP synthase complex

21 p687 Oxidative phosphorylation in brown fat tissue is uncoupled with ATP synthesis

22 p718 Regulation

23

24 NADH transport NADH produced by glycolysis must be transported into mitochondria to produce ATP. However, NADH cannot enter mitochondria directly. Instead it is transported by the form of malate or glycerol 3-phosphate.

25 Aspartate p715 Malate-aspartate shuttle NADH NAD+ OAA malate Malate dehydrogenase NAD+ NADH OAA Glutamate  -KG Malate dehydrogenase Aspartate aminotransferase

26 NAD+ Glycerol 3- phosphate p715 Glycerol 3-phosphate shuttle NADH DHAP FAD FADH2 Q Cytosolic glycerol 3- phosphate dehydrogenase Glycolysis III

27 NADH GlcG6PF6P F1,6BP G3P DHAP 1,3BPG 3-PGA2-PGA PEP Pyruvate NADH FADH2 NADH Malate- aspartate shuttle Glycerol 3- phosphate shuttle

28 p720 Mitochondrial genome

29 p35 Mitochondrion is probably evolved from endosymbiotic bacteria

30 Mitochondrial encephalomyopathies Mutations in mitochondrial genes cause mitochondrial encephalomyopathies that affecting primarily the brain and skeletal muscle. Because infants inherit their mitochondria from their mothers, so mitochondrial encephalomyopathies are maternal-linked.

31 Leber’s hereditary optic neuropathy (LHON) LHON is the result of defective mitochondrial genes that are involved in electron transfer. Vision loss usually occurs between the ages of 15 and 35.

32 Myoclonic epilepsy and ragged- red fiber disease (MERRF) Mutation in the mitochondrial gene that encodes a tRNA specific for lysine (lysyl-tRNA) results in MERRF. Synthesis of several proteins require this tRNA is interrupted.

33 p720 MERRF MERRF patients often have abnormally shaped mitochondria containing paracrystalline structures. This lysyl-tRNA mutation is also one of the causes of adult- onset (type II) diabetes.

34 Many respriatory proteins are encoded by mitochondria

35 Bacteria do have respiratory chain enzymes For example, E. coli has NAD-linked electron transfer from substrate to O 2, coupled to the phosphorylation of cytosolic ADP.

36 Mitochondria, apoptosis, and oxidative stress Mitochondria is not only involved in ATP synthesis. It is also involved in cellular damage and death.

37 The role of mitochondria in apoptosis When cell receives a signal for apoptosis, one consequence is the permeability of the outer mitochondrial membrane will increase, allowing cytochrome c release. The release of cytochrome c will activate caspase 9, which will initiate the protein degradation process.

38 Mitochondria can produce superoxide free radical


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