A Levels Biology (9700)•9700/12/M/J/20

Explanation
Triglyceride synthesis via esterification releases water per bond
Steps:
- Glycerol molecule has three hydroxyl groups that react with fatty acids.
- Each reaction forms an ester bond through dehydration synthesis.
- Three fatty acids attach, creating three ester bonds.
- Each bond formation produces one water molecule, totaling three.
Why A is correct:
- The balanced equation for triglyceride formation is glycerol + 3 fatty acids → triglyceride + 3 H₂O, confirming three water molecules from three esterifications.
Why the others are wrong:
- B: Applies to diglyceride (two fatty acids), not full triglyceride.
- C: Represents only one ester bond, ignoring the other two.
- D: Incorrect, as esterification is a condensation reaction that always produces water.
Final answer: A
Topic: Carbohydrates and lipids
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