Glycolysis

Pathways Cytosol Complexity: medium

Description

Glycolysis is the cytosolic pathway converting glucose to pyruvate. Ten enzymatic steps; net yield 2 ATP, 2 NADH per glucose. Investment phase (steps 1–5) consumes 2 ATP; payoff phase (6–10) produces 4 ATP, 2 NADH. Pyruvate fate depends on oxygen: aerobic conditions route it to acetyl-CoA and the Krebs cycle; anaerobic conditions reduce it to lactate for NAD+ regeneration.

Pathway Flowchart

graph TD A[Glucose] --> B[Hexokinase] B --> C[Glucose-6-P] C --> D[Phosphoglucose Isomerase] D --> E[Fructose-6-P] E --> F[Phosphofructokinase-1] F --> G[Fructose-1,6-BP] G --> H[Aldolase] H --> I[GAP] H --> J[DHAP] J --> K[Triose Phosphate Isomerase] K --> I I --> L[GAP Dehydrogenase] L --> M[1,3-BPG] M --> N[Phosphoglycerate Kinase] N --> O[3-Phosphoglycerate] O --> P[Phosphoglycerate Mutase] P --> Q[2-Phosphoglycerate] Q --> R[Enolase] R --> S[PEP] S --> T[Pyruvate Kinase] T --> U[Pyruvate] U --> V{O2 Available?} V -->|Yes| W[Pyruvate Dehydrogenase] V -->|No| X[Lactate Dehydrogenase] W --> Y[Acetyl-CoA] Y --> Z[TCA Cycle Input] X --> AA[Lactate] style A fill:#ff6b6b,color:#fff style B fill:#51cf66,color:#fff style C fill:#74c0fc,color:#fff style D fill:#51cf66,color:#fff style E fill:#74c0fc,color:#fff style F fill:#51cf66,color:#fff style G fill:#74c0fc,color:#fff style H fill:#51cf66,color:#fff style I fill:#74c0fc,color:#fff style J fill:#74c0fc,color:#fff style K fill:#51cf66,color:#fff style L fill:#51cf66,color:#fff style M fill:#74c0fc,color:#fff style N fill:#51cf66,color:#fff style O fill:#74c0fc,color:#fff style P fill:#51cf66,color:#fff style Q fill:#74c0fc,color:#fff style R fill:#51cf66,color:#fff style S fill:#74c0fc,color:#fff style T fill:#51cf66,color:#fff style U fill:#74c0fc,color:#fff style V fill:#b4b4dc,color:#000 style W fill:#51cf66,color:#fff style X fill:#51cf66,color:#fff style Y fill:#74c0fc,color:#fff style Z fill:#b197fc,color:#fff style AA fill:#b197fc,color:#fff

Color Scheme (6-Color System)

Red
Triggers & Inputs
Yellow
Structures & Objects
Green
Processing & Operations
Blue
Intermediates & States
Violet
Products & Outputs
Lavender
Decision Diamonds (OR/AND)
📊 Scientific Accuracy

This flowchart is based on verified biochemical data from peer-reviewed literature. All enzymatic steps, intermediates, and regulatory points have been validated against primary research sources and standard biochemistry textbooks. The model represents the current scientific consensus on glycolysis as a central metabolic pathway. The OR gate accurately represents the branching of pyruvate fate based on oxygen availability (aerobic vs. anaerobic metabolism).

📚 Sources & Citations
Berg JM, Tymoczko JL, Stryer L. Biochemistry. 9th ed. W.H. Freeman. 2019. Standard reference for glycolytic pathway.
Fothergill-Gilmore LA, Michels PA. Evolution of glycolysis. Progress in Biophysics and Molecular Biology. 1993.
Plaxton WC. The organization and regulation of plant glycolysis. Annual Review of Plant Physiology and Plant Molecular Biology. 1996.
📋 Metadata
Process Statistics

Nodes: 27 | Edges: 27 | OR Gates: 1 | AND Gates: 0

OR gate: O2 Available? (one edge in, two out: Yes → acetyl-CoA/TCA; No → lactate). Sequential AND: DHAP and GAP both required for payoff phase (convergence via TIM); shown as sequential steps, not a diamond.