What are the stages of anaerobic respiration?

The stages of anaerobic respiration are the investment and payoff phase.

1. During the investment phase, 2 molecules of ATP are acquired/consumed for each glucose sugar. Glycolysis is initiated with hexokinase phosphorylating glucose into glucose-6 phosphate(G6P). This step involves the transfer of the first of two phosphates to glucose and is irreversible. Next, phosphoglucose isomerase converts G6P into fructose-6-phosphate (F6P). Phosphofructokinase then adds on the second phosphate group. It uses the second ATP molecule and converts F6P into fructose 1,6, biphosphate. This is the rate-limiting step of the process and is also irreversible. Next, fructose 1,6 bisphosphate cleaves into two 3-carbon sugars which are the substrates for fructose-bisphosphate aldolase. In specific, fructose-bisphosphate is cleaved to form dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate (G3P). DHAP is converted to G3P through triosephosphate isomerase. 
2. During the payoff phase, 4 ATP and 2 NADH molecules are produced from each glucose. There are two 3-carbon sugars for each glucose molecule in this phase initially. Glyceraldehyde-3-phosphate converts G3P to 1,3-diphosphoglycerate by reducing NAD+ into NADH. The 1,3, diphosphoglycerate then loses a phosphate via phosphoglycerate kinase to form 3-phosphoglycerate and generate an ATP molecule via phosphorylation. 2 ATP are now formed from each 3-carbon sugar. Next, the 3-phosphoglycerate is converted into 2-phosphoglycerate through phosphoglycerate mutase. Enolase then converts 2-poshpglcyerate into phosphoenolpyruvate (PEP). During the last step of the payoff phase, pyruvate kinase converts PEP to pyruvate and phosphorylates ADP to ATP, subsequently generating 2 additional ATP molecules (through substrate-level phosphorylation). This is also an irreversible step in the process. To summarize, at the end of the payoff phase a net of 2 ATP is formed per glucose sugar, as well as 2 NADH and 2 pyruvate molecules. Each step in the payoff phase happens twice per glucose sugar since glucose divides to form 2 molecules of glyceraldehyde-3-phosphate.