How many pyruvic acid molecules form from 206 glucose molecules in NEET 2026?
D) 412 molecules is the answer to this glycolysis NEET 2026 question, because each glucose molecule yields two pyruvic acid molecules. The task is: if 206 glucose molecules complete glycolysis, what is the resulting number of pyruvic acid molecules?
The source is NEET 2026, 21 June re-held examination, Code-50, Biology. The question bank classifies it as medium difficulty; that is not an official NTA rating. The calculation needs the glucose-to-pyruvate ratio, not the total energy yield of respiration.
Why does one glucose molecule produce two pyruvate molecules?
One glucose molecule contains six carbon atoms, and glycolysis produces two pyruvate molecules containing three carbon atoms each. The supplied solution anchors this fact to NCERT Class 11 Biology, Chapter 14, Respiration in Plants, in the glycolysis section.
The carbon relationship establishes the product count:
This arrow summarises the conversion; it does not represent a single direct reaction. During glycolysis, the six-carbon substrate splits into two three-carbon intermediates, which proceed through further reactions to form pyruvate.
Glycolysis occurs in the cytoplasm through 10 enzyme-catalysed reactions. It has no direct oxygen requirement and is the shared initial pathway for aerobic and anaerobic respiration.
Carbon accounting establishes the multiplier before you substitute the question’s glucose count. Each three-carbon intermediate proceeds to a pyruvate molecule, so count both branches of the split, not just one.
How do you calculate the answer and check it?
Multiply the glucose count by two to obtain 412 molecules of pyruvic acid, option D. This follows the official solution’s direct-scaling method: establish the biological ratio, then apply it to the given count.
Write the rule before substituting, keeping the molecule labels in the conversion factor:
Verify the answer by checking carbon atoms. This checks the result rather than replacing the direct-scaling method:
Both totals match. ATP yield, NADH yield and later respiratory products are separate quantities; none changes the multiplier required for this pyruvic acid count.
Why is option A, 206 molecules, incorrect?
Option A uses one product molecule per glucose molecule instead of two. The incorrect setup is:
Carrying the starting molecule count unchanged into the product count ignores the splitting of a six-carbon substrate into two three-carbon products. Carbon atoms are conserved, but the number of molecules need not remain unchanged.
If only 206 three-carbon pyruvate molecules formed, they would account for only half the carbon entering as glucose. That fails the carbon check for complete glycolysis.
Correct the method by writing the pathway ratio before using the question’s number. Then multiply the given glucose count by two:
How do you solve related glycolysis counting questions?
Multiply for a glucose-to-pyruvate count, divide for the reverse count, and label energy products separately. These are author-created related practice questions from Respiration in Plants, not additional verified NEET PYQs.
Question 1: If glycolysis produces 206 pyruvate molecules, how many glucose molecules entered?
103 glucose molecules entered the pathway. Each glucose accounts for two pyruvates, so divide the given product count by two:
Division is correct because this question works backwards from product count to starting count. The original question gives glucose and asks for pyruvate, so it requires multiplication; this reverse calculation does not mean glycolysis itself runs backwards.
Question 2: What are the net ATP and NADH yields from 206 glucose molecules?
The yields are 412 net ATP molecules and 412 NADH molecules. Glycolysis gives two net ATP and two NADH per glucose, so calculate each separately:
These numbers match the pyruvate count, but ATP, NADH and pyruvate are not interchangeable quantities. Label the requested product, and do not confuse net glycolytic ATP with total ATP from respiration.
Question 3: Where does glycolysis occur, and does it directly require oxygen?
Glycolysis occurs in the cytoplasm and has no direct oxygen requirement. It is the shared initial pathway for aerobic and anaerobic respiration.
Subsequent processing of pyruvate lies outside the original question’s endpoint. Stop counting when glycolysis has produced pyruvate.
Retrieval rule: glucose to pyruvate, multiply by two; pyruvate to glucose, divide by two.
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Frequently asked questions
How many pyruvic acid molecules form from 206 glucose molecules?
Complete glycolysis of 206 glucose molecules produces 412 pyruvic acid molecules, so option D is correct. Each six-carbon glucose yields two three-carbon pyruvate molecules: 206 × 2 = 412. Carbon atoms are conserved, but the number of molecules does not remain unchanged.
How many glucose molecules are needed to produce 206 pyruvate molecules?
103 glucose molecules are needed because each glucose produces two pyruvate molecules. Divide the pyruvate count by two: 206 ÷ 2 = 103. This is a reverse calculation, not a claim that glycolysis runs backwards.
What are the net ATP and NADH yields from 206 glucose molecules in glycolysis?
Glycolysis of 206 glucose molecules yields 412 net ATP molecules and 412 NADH molecules. Each glucose yields two net ATP and two NADH, so multiply 206 by two for each product separately. Net glycolytic ATP is not the total ATP yield of respiration.
Where does glycolysis occur and does it require oxygen?
Glycolysis occurs in the cytoplasm through 10 enzyme-catalysed reactions and has no direct oxygen requirement. It is the shared initial pathway for aerobic and anaerobic respiration.