Gluconeogenesis

Gluconeogenesis is the production of  glucose mostly from lactate, which the end product of glycolysis. Other precursors molecules such as glycerol and amino acids, repsectively derived from fat and protein catabolism.
Essentially, gluconeogenesis(glucose synthesis) in a sense may seems to be the reverse reaction of glcolysis(glucose breakdown). However, these two reactions are not completely irreversible, due to the "one-way" steps along the individual biochemical processes as well as the different catalysing enzymes involved.