Respiration Pathways & Energy Production — NEET Biology
📚 Practice ConceptDistinguish between the following: (a) Aerobic respiration and Anaerobic respiration (b) Glycolysis and Fermentation (c) Glycolysis and Citric acid Cycle
Which of the following statements accurately describe the energy yield and ATP synthesis during fermentation? S1: The net gain of ATP molecules from the fermentation of one glucose molecule is typically 2 ATP, which are generated during glycolysis. S2: Fermentation pathways, unlike aerobic respiration, involve both substrate-level phosphorylation and oxidative phosphorylation for ATP synthesis. S3: In fermentation, a significant portion of the energy stored in glucose is released as heat and not trapped in ATP due to incomplete oxidation. S4: The ATP yield in fermentation is maximized under conditions of high oxygen availability, enhancing the efficiency of the process. S5: The "energy currency of the cell," ATP, is not produced at all during anaerobic fermentation.
View solution & NCERT explanation
Correct answer: A — S1 and S3 are correct.
The core concept is the low ATP yield in fermentation and the reasons behind it. S1 is correct. NCERT states, "In fermentation there is a net gain of only two molecules of ATP for each molecule of glucose degraded to pyruvic acid". These ATPs are from glycolysis (substrate-level phosphorylation). S2 is incorrect. Fermentation pathways only involve substrate-level phosphorylation during glycolysis. Oxidative phosphorylation occurs only in aerobic respiration. S3 is correct. NCERT states, "In both lactic acid and alcohol fermentation not much energy is released; less than seven per cent of the energy in glucose is released and not all of it is trapped as high energy bonds of ATP." This is due to incomplete oxidation. S4 is incorrect. Fermentation occurs under anaerobic conditions; oxygen availability would shift metabolism towards aerobic respiration, not maximize fermentation ATP yield. S5 is incorrect. A net of 2 ATP molecules are produced during fermentation, specifically during glycolysis. Fermentation yields a low net of 2 ATP per glucose, exclusively via substrate-level phosphorylation during glycolysis, due to incomplete oxidation and anaerobic conditions.
What does NCERT say about Distinguish between following Aerobic?
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Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.