| Term | Definition |
| lactic acid fermentation | •The conversion of pyruvate to lactate with no release of carbon dioxide. |
| light reactions | The photosynthetic process in which solar energy is harvested and transferred into the chemical bonds of ATP; can occur only in light. |
| logistic growth | •Growth rates regulated by internal and external factors that establish an equilibrium with environmental resources |
| membrane potential | the voltage difference (or electrical potential difference) between the interior and exterior of a cell |