Biochemical Pathways

Question

How do biochemical pathways like glycolysis and the Krebs cycle contribute to cellular respiration?

Answer 1

When we talk about cellular respiration, we're really referring to the entire process of generating usable energy in the form of ATP from biological fuel (glucose) in an aerobic environment. Glycolysis and the Krebs cycle are two important parts of that!

Focusing on energetic products, in glycolysis we convert glucose to pyruvate, NADH, and ATP. The resulting pyruvate can then be converted to acetyl-CoA, which is used in the Krebs cycle to produce ATP, NADH, and FADH₂.

FADH₂ and NADH are electron carriers that then participate in the electron transport chain, creating a proton gradient across the inner membrane of the mitochondria that ATP synthase uses to generate a bunch of ATP!

So the overall order of pathways in cellular respiration is something like Glucose in --> glycolysis --> Krebs cycle --> electron transport chain --> ATP out. Keep in mind this is a simplified overview of the many reactions involved. Hope this helps!