Chapter 3: Metabolic Processes and Energy
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SBI4U Biology · 3.3
Activation energy as a barrier
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Activation energy as a barrier
- Activation energy is the boost reactants need to break their first bonds and reach the transition state.
- A reaction with a negative ΔG still will not start until the barrier is crossed; sucrose can sit unchanged for years.
- Thermodynamics says whether a reaction can proceed, not how fast.
- Reactants reach the transition state only when they collide with enough force and in the correct orientation.
- A spark starts propane burning; thermal energy is the usual source.
- Heating is a poor method in cells: it denatures proteins and speeds up every reaction.