Chapter 15 · Chemical Equilibrium
15.1Life: Controlled Disequilibrium
7 min · two checks
Predict
If equilibrium is the natural destination, why aren’t living cells at equilibrium?
The idea
- Contrast equilibrium with a maintained steady state.
- Say why equilibrium is not “nothing happening.”
Many chemical systems slide toward a balance of forward and reverse reactions and then stay there. A living cell cannot let every reaction reach that balance; if ATP, ion gradients, and food all sat at equilibrium, the cell would be dead. Organisms take in energy and matter to hold themselves away from equilibrium. That is a controlled disequilibrium, a steady flow, not a stopped reaction.
The rest of this chapter studies the balance itself, because you cannot understand the effort of staying away from it until you know what the balance looks like. Equilibrium is dynamic. Products form and reactants re-form at equal rates. The concentrations stop changing. The chemistry does not.
Keep these
- Equilibrium: forward and reverse rates equal, concentrations steady.
- Life maintains a steady state away from equilibrium by using energy.
- “Balanced” does not mean “stopped.”