explain the steps of the Krebs cycle

I can outline the overall process and a few specific enzymatic steps, but I cannot walk through all eight steps in detail from this evidence alone.

Location and Starting Point

.

Key Enzymatic Steps Described in Evidence

1. Condensation — forming citrate: The enzyme citrate synthase condenses acetyl-CoA with oxaloacetate to form citrate, initiating the cycle

.

1. Oxidative decarboxylations: A series of oxidative decarboxylation reactions follows, releasing two molecules of CO₂ and ultimately regenerating oxaloacetate to allow the cycle to continue

.

1. Succinate dehydrogenase (SDH) step: Xekouki & Stratakis (2012) identify succinate dehydrogenase (SDH), also known as mitochondrial complex II, as a critical step of the Krebs cycle. It is bound to the inner mitochondrial membrane and transfers electrons directly to the ubiquinone pool, serving a dual role in both the cycle and the respiratory chain .

Energy and Metabolite Outputs Per Turn

:

• 3 NADH
• 1 FADH₂
• 1 GTP/ATP (via substrate-level phosphorylation)

.

Key Intermediates

Two notably accumulating intermediates are citrate and succinate. Williams & O'Neill (2018) note that citrate can be exported from the mitochondria via the mitochondrial citrate carrier, where it plays roles beyond energy metabolism, including fatty-acid synthesis and protein acetylation in the cytosol .

What This Evidence Cannot Cover

The retrieved evidence does not detail every individual step (e.g., aconitase, isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, succinyl-CoA synthetase, fumarase, or malate dehydrogenase reactions). For a complete step-by-step mechanistic account, additional sources would be needed.