AP BIOLOGY

Detailed explanation-1: -During glycolysis, glucose ultimately breaks down into pyruvate and energy; a total of 2 ATP is derived in the process (Glucose + 2 NAD+ + 2 ADP + 2 Pi–> 2 Pyruvate + 2 NADH + 2 H+ + 2 ATP + 2 H2O).

Detailed explanation-2: -In poorly oxygenated tissue, glycolysis produces 2 ATP by shunting pyruvate away from mitochondria and through the lactate dehydrogenase reaction.

Detailed explanation-3: -Glycolysis starts with one molecule of glucose and ends with two pyruvate (pyruvic acid) molecules, a total of four ATP molecules, and two molecules of NADH.

Detailed explanation-4: -First ATP is produced when glyceraldehyde-3-phosphate ⇢ 1, 3 diphosphoglycerate. Secondly ATP is produced when phosphoenolpyruvate ⇢ pyruvate. These reactions occur twice for both molecules of 3-phosphate. Thus, a total of 4 ATPs are produced during glycolysis.

Detailed explanation-5: -These two steps take place two times in glycolysis. Hence, four molecules of ATP are synthesized. The steps such as conversion of glucose to glucose-6 phosphate and fructose-6 phosphate to fructose-1, 6 bisphosphate consumed two molecules of ATP. Thus net gain of ATP molecules in glycolysis is 2.