AP BIOLOGY

Detailed explanation-1: -One glucose molecule yields four ATP molecules in total during glycolysis. Since 2 ATP molecules are used up in the first phase of glycolysis, there is a net gain of 2 ATP molecules.

Detailed explanation-2: -Explanation: In glycolysis, the net gain of ATP molecules is 2. Two ATP per glucose molecule are required to initiate the process, then a total of four ATP are produced per molecule of glucose.

Detailed explanation-3: -Although four ATP molecules are produced in the second half, the net gain of glycolysis is only two ATP because two ATP molecules are used in the first half of glycolysis.

Detailed explanation-4: -2 molecules of ATP are utilised in the glycolysis. One molecule of ATP is utilised when glucose is converted to glucose-6-phosphate and the other is utilised when fructose-6-phosphate is converted to fructose-1, 6-bisphosphate. So, the net gain of ATP molecules during glycolysis is 2.

Detailed explanation-5: -Two molecules of triose-phosphate produced per molecule of glucose yields 4–6 ATP. These, in addition to the 2 ATP made from glycolysis, gives a total of 6–8 molecules of ATP per glucose molecule.