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Cell Respiration Releases Energy From Organic Compounds to Make ATP
- Cell respiration is the controlled release of energy from organic compounds to produce ATP, the energy currency of cells.
- Cells break down carbon compounds such as glucose and fatty acids to extract the energy stored in their chemical bonds.
- This energy is released through oxidation and captured in ATP molecules.
Note
- Oxidation is the loss of electrons or hydrogen atoms.
- Reduction is the gain of electrons or hydrogen atoms.
- These reactions are coupled and form the basis of energy transfer in cells.
Glucose and Fatty Acids Are the Main Respiratory Substrates
Cells can use many organic compounds, but glucose and fatty acids are the principal substrates.
- Glucose
- Glucose is a 6-carbon sugar and the most commonly used substrate.
- It is broken down during glycolysis into two molecules of pyruvate (3C).
- Pyruvate can then enter the mitochondria for complete oxidation in aerobic respiration, or be converted to other products in anaerobic respiration.
- Fatty acids
- Fatty acids are long carbon chains that are highly energy-dense.
