Metabolic Pathway Locations

[taylorswift132]

So I still seem to be getting confused with where each metabolic pathway (ie. glycolysis, TCA, ETC, anaerobic pathways) occur in the cell and how the anaerobic pathways fit into everything. If someone doesn't mind posting a quick summary of these locations (and how they are transferred between), that would be SO helpful!
Thanks so much!

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[theonlytycrane]

An anaerobic pathway implies no oxygen. An ancient example is glycolysis. Cells convert glucose (sugar) to pyruvate and generate a bit of ATP (energy) along with electron carriers (NADH).

If cells have a mitochondria and oxygen is available, pyruvate gets transported into the mitochondria and transformed into acetyl-coa. Acetyl-coa can jump into the TCA (Kreb's cycle) to get oxidized and generate some electron carriers (NADH & FADH2) and GTP (energy). The point of this is for the electron carriers to drop off the electrons to the ETC in the mitochondrial inner membrane. The electrons get passed along the ETC and generate a proton gradient in the inter-membrane space that drives ATP synthesis via ATP synthase. The final electron acceptor in the ETC is oxygen, which is why this path is called "aerobic".

Location wise, glycolysis (anaerobic) occurs in the cytosol and TCA / ETC (aerobic) occur in the mitochondria. Hope this helps!

 

[taylorswift132]

Thanks! How does ketogenesis play into all of this?

 

[theonlytycrane]

When we run low on glucose and glycogen stores, we need to send molecules to important organs like the brain to keep them going. We can break down fats into acetyl-coa and combine them into ketone bodies to send as energy in place of glucose. The ketone bodies get oxidized for ATP generation.

 

[taylorswift132]

Thank you!!!