Biology · Respiration in Plants · NEET
Glycolysis does NOT use oxygen at any step, so it can run whether oxygen is present or not. This is why it is common to both aerobic respiration and fermentation (anaerobic). In anaerobic organisms it is the only respiratory process. So do not label glycolysis itself as 'aerobic' or 'anaerobic' — it is oxygen-independent; what happens to its product (pyruvic acid) afterwards decides the aerobic or anaerobic route.
Glycolysis occurs in the cytoplasm (cytosol) of the cell, not inside the mitochondria. This is a very common NEET match-the-column point. In contrast, the Krebs cycle runs in the mitochondrial matrix and the ETS is on the inner mitochondrial membrane. Because it is cytoplasmic and oxygen-free, glycolysis is present in all living organisms, including bacteria that have no mitochondria.
EMP stands for the surnames of the three scientists who worked out the scheme of glycolysis: Gustav Embden, Otto Meyerhof and J. Parnas. So 'EMP pathway' and 'glycolysis' mean exactly the same thing. NEET often gives 'EMP pathway' in one column and expects you to match it to 'glycolysis'.
The end product of glycolysis is pyruvic acid (pyruvate). One glucose gives two molecules of pyruvic acid, because a 6-carbon glucose is split into two 3-carbon pyruvates. Glucose is only partially oxidised here — the pyruvate still holds most of the energy, which is released later in the Krebs cycle and ETS.
Glycolysis produces 4 ATP by substrate-level phosphorylation but spends 2 ATP in the early investment steps, so the NET gain is 2 ATP per glucose. It also makes 2 molecules of NADH. Remember: gross ATP = 4, ATP invested = 2, NET ATP = 2.
Conversion of glucose to glucose-6-phosphate, the first irreversible reaction of glycolysis, is catalyzed by
What is the net gain of ATP when each molecule of glucose is converted to two molecules of pyruvic acid?
How many molecules of pyruvic acid are produced at the end of glycolysis from 206 molecules of glucose?
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Glycolysis is the partial oxidation of one glucose molecule into two molecules of pyruvic acid through ten enzyme-catalysed steps in the cytoplasm.
Yes. Glycolysis is also called the EMP pathway, named after Embden, Meyerhof and Parnas who described its scheme.
Yes, glycolysis occurs in the cytoplasm of all living organisms because it needs no oxygen and no mitochondria. In anaerobic organisms it is the only respiratory process.
From one glucose you get 2 pyruvic acid, a net 2 ATP and 2 NADH + H+.
Glucose has 6 carbons; the pathway breaks it at the middle stage (fructose-1,6-bisphosphate) into two 3-carbon molecules, which are then converted to two pyruvic acid molecules.
