Such reactions are said to be reversible. Metabolic reactions with large, negative ΔG are said to be irreversible. ... Because they are far from equilibrium, irreversible reactions are optimal points at which to control the flux through a metabolic pathway.

Why is combustion irreversible?

Combustion reactions are generally irreversible. Combustion occurs whenever a fuel burns. ... In a complete combustion reaction, fuel and oxygen are the reactants and the products are carbon dioxide and water. These two products cannot react to reform the fuel and oxygen, so the reaction is irreversible.

Is metabolism a reversible process?

Metabolic pathways are often considered to flow in one direction. Although all chemical reactions are technically reversible, conditions in the cell are often such that it is thermodynamically more favorable for flux to proceed in one direction of a reaction.