* Endergonic Reactions: These reactions require an input of energy to occur. They have a positive change in Gibbs free energy (ΔG > 0), meaning they are not spontaneous and require energy from the surroundings.
* Exergonic Reactions: These reactions release energy as they proceed. They have a negative change in Gibbs free energy (ΔG < 0), meaning they are spontaneous and can occur without external energy input.
Examples of uphill reactions:
* Photosynthesis: Plants convert light energy into chemical energy in the form of glucose.
* Protein synthesis: Building proteins from amino acids requires energy.
* Muscle contraction: Requires energy from ATP.
Important Note: The terms "uphill" and "downhill" are often used to describe the relative energy change of a reaction, but they aren't strictly scientific terms. It's more accurate to use the terms "endergonic" and "exergonic" to describe reactions based on their free energy changes.
