this is all just from my head, so don't quote me, but basically-
anaerobic = not enough o2
so glycolysis can happen but ONLY glycolysis
glycolysis produces 2x pyruvate molecules and 2x reduced NAD
IN ANIMALS; lactate is produced
so; pyruvate + red NAD ---> lactate + oxi NAD
IN PLANTS/YEAST;
pyruvate + red NAD --> CO2 + ethanol
basically purpose is to still supply ATP but only 2ATP molecules which is very low compared to anaerobic respiration
it is never one or the other, if there is low O2 then anaerobic resp will happen with a bit of aerobic respiration
it is good because it supplies some ATP but lactate builds up in muscles and causes muscle fatigue= bad
redNAD needs to be converted back to oxi NAD so it can be reused in glycolysis in the cytoplasm of cells
hope this makes sense- this is the basics and probably the only stuff you could get asked on it