Cellular Respiration Across All Organisms — NEET Biology
📚 Practice ConceptAll of us breathe to live, but why is breathing so essential to life? What happens when we breathe? Also, do all living organisms, including plants and microbes, breathe? If so, how?
Which of the following statements correctly describe why glycolysis is considered a universal pathway? S1: Glycolysis is the only pathway capable of generating ATP in multicellular organisms. S2: It is present in the cytoplasm of all known living organisms, including prokaryotes and eukaryotes. S3: The enzymatic machinery for partial oxidation of glucose without oxygen is retained by all living organisms. S4: In anaerobic organisms, glycolysis is the sole process involved in the breakdown of glucose for energy. S5: It is the exclusive source of NADH + H+ production in both aerobic and anaerobic respiration.
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Correct answer: B — S2, S3, S4
Let's evaluate each statement regarding the universality of glycolysis: S1: Glycolysis is not the only pathway capable of generating ATP in multicellular organisms; aerobic respiration (Krebs cycle and oxidative phosphorylation) also generates significant ATP. This statement is incorrect. S2: Glycolysis occurs in the cytoplasm of the cell and is present in all living organisms, confirming its presence in both prokaryotes and eukaryotes. This statement is correct. S3: All living organisms retain the enzymatic machinery to partially oxidize glucose without the help of oxygen through glycolysis. This highlights its universality and ancient origin. This statement is correct. S4: In anaerobic organisms, fermentation (which starts with glycolysis) is the only process of respiration, meaning glycolysis is the sole process for glucose breakdown to release energy under these conditions. This statement is correct. S5: While glycolysis produces NADH + H+, the Krebs cycle (in aerobic respiration) also produces NADH + H+ (and FADH2). So, it's not the exclusive source in both aerobic and anaerobic respiration. This statement is incorrect. Therefore, statements S2, S3, and S4 correctly describe why glycolysis is considered a universal pathway.
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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.