Compare the entry-level substrates, products, and metabolic purposes of glycolysis and gluconeogenesis.

Glycolysis is the process by which glucose molecules are broken down to pyruvate molecules while gluconeogenesis is the process by which glucose is synthesized from non-carbohydrate molecules. For glycolysis, the entry level substrate is glucose, the product is pyruvate and energy in form of ATP and the metabolic purpose of glycolysis is energy production. For gluconeogenesis, the entry level substrate can be lactate, pyruvate, glycerol or glucogenic amino acid, the product is glucose and the purpose of the process is generation of glucose.