Electron transfer in Mitochondria: NADPH. What's the role of the mitochondria in this?

[Kemosabe]

This is listed under section 1D on the mcat, and I'm just wondering if I'm missing anything: From what I understand, The pentose phosphate pathway is the main creator of NADPH during its oxidative phase, but TPP occurs in the cytosol. Fatty acid synthesis also occurs in the cytosol and turns NADPH + H+ into NADP+. I'm just wondering what the mitochondria's involvement in this is? from what I understand acetyl-coa can't be shuttled from the mitochondria into the cytoplasm so it must be turned into citrate which is then shuttled into the cytosol, which is then converted into OAA and pyruvate which uses NADPH. Is that right? What other roles does NAPDH have in the mitochondria?

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[shefv]

Some NADPH is also made in the mitochondria through other pathways.

 

[Kemosabe]

Some NADPH is also made in the mitochondria through other pathways.

What are the main ones we should know for the mcat, aside from their association with fatty acid synthesis and the pentose phosphate pathway?

 

[EParker37]

The primary source is the pentose phosphate pathway, in mitochondria, there are three pathways: The pathways of NADPH generation in steroidogenic mitochondria include three major routes catalyzed by: 1. NADP-linked malic enzyme, 2. NADP-linked isocitrate dehydrogenase, and 3. nicotinamide nucleotide transhydrogenase (NADH Kinase). But, for the MCAT I would expect that they just want you to understand that the mitochondria are a minor source of NADPH and the PPP is the primary source.

There is a pubmed article talking about the mitochondrial pathways if you have access: http://www.ncbi.nlm.nih.gov/pubmed/7588385