MBBS · Biochemistry

Glycolysis

Glycolysis converts one six-carbon glucose molecule into two three-carbon pyruvate molecules in the cytosol while producing a small amount of ATP and reducing equivalents.

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Glycolysis: carbon and energy overview

Original conceptual SVG · scalable
Glucose · 6 carbonsEnergy investment−2 ATPTwo 3-carbon intermediates+4 ATP +2 NADH2 × PyruvateNET BALANCE+2 ATP · +2 NADHCytosolnot mitochondria

One glucose → two pyruvate. ATP and NADH accounting is net per glucose; ten enzymatic steps are simplified to four blocks.

Concept 01

Organize the ten reactions

The investment phase uses two ATP equivalents. The payoff phase yields four ATP equivalents and two NADH per glucose under the standard pathway.

Concept 02

Remember key regulation points

Hexokinase or glucokinase, phosphofructokinase-1 and pyruvate kinase catalyse important irreversible steps and are regulated in tissue-specific ways.

Concept 03

Follow pyruvate

In aerobic tissues pyruvate can enter mitochondrial metabolism via acetyl-CoA. When oxidative NADH reoxidation is limited, lactate dehydrogenase helps regenerate cytosolic NAD+ for continued glycolysis.

Education / safety note: The diagram is a simplified carbon and energy balance; it omits intermediate steps and tissue-specific regulation.

Reference and next reading

Explore the original curriculum and publisher-hosted resources for full-depth reading; this note is an original schematic introduction, not an exhaustive chapter.

Official / publisher source: NMC official CBME Curriculum 2024 and current regulations index ↗Official / publisher source: OpenStax Anatomy and Physiology 2e (read on publisher site) ↗Official / publisher source: PubMed ↗