Harden and Young's ester is formed during glycolysis from

Besides the net gain of $2 \ ATP$ molecules in glycolysis,which other molecules are simultaneously formed?

In which of the following steps of glycolysis is $ATP$ utilized?

Given below are two statements:
$Statement-I$: Glycolysis is a common step in anaerobic as well as aerobic respiration and it occurs in the mitochondrial matrix.
$Statement-II$: The first five steps of glycolysis constitute its preparatory phase.
In the light of the above statements,choose the correct answer from the options given below.

During glycolysis or the $EMP$ pathway,how many net $ATP$ molecules are produced directly from one mole of glucose (in $ATP$)?

During phosphorylation in glycolysis,which $3C$ sugars are transformed into each other?