It is in the oxidation of NADH to NAD + that lactate dehydrogenase (LDH) plays an important role. LDH catalyzes the following reaction The lactate then diffuses out of the cell and the NAD + is used to continue glycolysis.It is in this manner that the cell continues to produce energy under anerobic conditions.
The right side will also have 3 carbon, 6 oxygen, and 4 hydrogen atoms. the atoms may come together to form a compound but it doesn't lose any atoms. Hope it helped!