For a reaction to be spontaneous, the change in free energy, D G, must be positive. Acetyl CoA contains a high energy thioester linkage. Glycolysis involves the breakdown of a 6 carbon sugar into two 4 carbon sugars generating a net of 4 ATP molecules. Lactose intolerance is due to the lack of b -galactosidase. High levels of phosphoenolpyruvate indicate that the energy charge of the cell is low and glycolysis speed up.
Polysaccharides lack directionality.
Coupled reactions allow a thermodynamically unfavored reaction to proceed.