Question 11 of 17intermediate🔧 ApplyNumerical2 marks

Work out how many ATP and NADPH molecules will be required to make one molecule of glucose through the Calvin pathway.

Correct Answer

18 ATP molecules and 12 NADPH molecules are required to make one molecule of glucose through the Calvin pathway.

Exercise: 11.7.2 The Calvin Cycle | Q: In-text 12 | (Chapter: Page 15)
For More Understanding

Explanation

The textbook states that for every CO₂ molecule entering the Calvin cycle, 3 molecules of ATP and 2 molecules of NADPH are required. Since 6 turns of the cycle are needed to synthesize one glucose molecule (fixing 6 CO₂ molecules), the total requirement is calculated by multiplying these values. This is confirmed by the table in the context showing the inputs and outputs of the Calvin cycle.

Solution Steps

  1. Step 1: For 1 CO₂ molecule fixed in the Calvin cycle, 3 ATP and 2 NADPH are required.

  2. Step 2: To make 1 glucose molecule, 6 turns of the Calvin cycle are required (6 CO₂ molecules are fixed).

  3. Step 3: Total ATP required = 3×63 \times 6 = 18 ATP molecules.

  4. Step 4: Total NADPH required = 2×62 \times 6 = 12 NADPH molecules.

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