Question

Nonproliferating cells use Oxidative Phosphorylation to generate ATP. However, rapidly proliferating cells depend on anaerobic glycolysis to generate ATP. Anaerobic glycolysis produces 2 molecules of ATP per molecule of glucose whereas oxidative phosphorylation generates 36 molecules of ATP per molecule of glucose.
Why do proliferating cells (which should need more energy than non‐proliferating cells) switch to a less efficient metabolism?

Answer 1

This is mainly due to the conditions. Anaerobic respiration can produce several waste products, such as ethanol or pyruvate, which are easy for cells to get rid of quickly. While aerobic waste products (CO2 and H2O) are even easier for the cell to deal with, it requires a massive amount of energy to make all the proteins and enzymes necessary for the Krebs Cycle, which is the process of aerobic respiration.

Basically, if there is a ton of food around and no need to squeeze every drop of energy out of it, many cells will perform anaerobic respiration. This frees up more ribosomes to make proteins needed for proliferation rather than proteins for the Krebs Cycle.

Sorry this isn't a more complete answer... metabolism isn't my specialty.

http://en.wikipedia.org/wiki/Cellular_respiration

Answer 2

The waste products of anaerobic respiration can be incorporated by cancer cells to into their biomass. The cell basically needs to accumulate nutrients to proliferate .And most proliferating cells including cancer cells adapt their metabolism for this purpose of nutrient accumulation.
Glycolysis gives a faster ATP yield than the slower aerobic respiration (Krebs cycle) . and the fermentation state or anaerobic part of glycolysis  conversion of pyruvate to lactate keeps the Glycolytic cycle going by supplying NAD+ molecules. So If you consume more glucose you would get a faster ATP yield in the time it takes to perform the Krebs cycle, plus waste products you can use for proliferation. So it gives you both time and nutrients .
Cancer cells / proliferating cells carry out both oxidative phosphorylation and aerobic glycolysis simultaneously. The rate of respiration of cancer cells is similar to normal cells but the glucose uptake is 10 times higher according to Warburg and co-workers .For every 13 glucose molecules taken up, 1 is oxidized via respiration, while the remaining 12 are split to form lactic acid . Thus, in the time that one glucose molecule produces 36 ATP via respiration, 24 additional ATP are generated via aerobic glycolysis. The respiration of cancer cells is small relative to the consumption of glucose, but not small relative to the respiration of normal cells . Glycolysis is not inefficient; even in the absence of dioxygen, cancer cells survive because lactic acid production via anaerobic glycolysis yields 2/3 of the ATP that a normal cell produces by respiration.

Answer 3

For proliferating cells its usualy a trade off between , fast ATP production and accumilating enough nutirents to make proliferation possible and consumeing enough of that ATP so that the glycolysis machinery doesnt shut down .

Answer 4

The above usually came to be known as the Warburg effect
http://en.wikipedia.org/wiki/Cellular_respiration
http://en.wikipedia.org/wiki/Lactic_acid_fermentation
http://en.wikipedia.org/wiki/Warburg_effect
http://en.wikipedia.org/wiki/Reverse_Warburg_Effect
http://www.sciencemag.org/content/324/5930/1029.abstract/reply#content-block