ATP
The energy of life itself. ATP (adenosine triphosphate) is the universal energy currency used by every cell in your body. Muscle contraction, nerve signaling, protein synthesis, DNA replication—everything runs on ATP. You produce roughly your body weight in ATP every single day.
What ATP Powers
Muscle Contraction
Every muscle fiber needs ATP to contract. Heart, skeletal, smooth muscle all require constant supply.
Nerve Signaling
Sodium-potassium pumps run on ATP. Maintaining nerve potential is energy-expensive.
Protein Synthesis
Building proteins from amino acids requires ATP. Muscles, enzymes, hormones—all need synthesis.
DNA Replication
Copying DNA for cell division is ATP-intensive. Repair processes also need ATP.
Active Transport
Moving molecules against concentration gradients. Nutrient absorption, waste export.
Signaling
ATP itself is a signaling molecule. Also converted to cAMP for hormone signaling.
How ATP is Made
1. Glycolysis
- Happens in cytoplasm
- Glucose → 2 pyruvate
- Produces 2 ATP (net)
- Doesn't need oxygen
- Fast but inefficient
2. Krebs Cycle
- Happens in mitochondrial matrix
- Pyruvate fully oxidized
- Produces 2 ATP
- Generates NADH, FADH2
- Feeds electron transport
3. Electron Transport
- Inner mitochondrial membrane
- NADH, FADH2 donate electrons
- Produces ~32 ATP
- Requires oxygen
- Most efficient pathway
What ATP Production Needs
Magnesium
ATP must be bound to Mg²⁺ to be biologically active. Mg-ATP is the functional form.
CoQ10
Essential electron carrier in chain. Without CoQ10, ATP synthesis stalls.
NAD+
Accepts electrons from fuel. Shuttles them to electron transport chain.
B Vitamins
B1, B2, B3, B5 all required as cofactors in energy metabolism.
Iron
Cytochromes in electron transport chain contain iron. Anemia = low ATP.
Oxygen
Final electron acceptor. Without O₂, only glycolysis works (2 ATP vs 36).
When ATP Production Fails
Fatigue
Most obvious symptom. Muscles can't contract, brain can't focus. Chronic fatigue often = mitochondrial issue.
Organ Dysfunction
High-energy organs fail first: heart, brain, muscles, kidneys. Mitochondrial diseases devastate these.
Accelerated Aging
Repair processes need ATP. Less ATP = less repair = faster aging. Mitochondrial decline is aging.