Question 9
When two monosaccharide molecules join to form a disaccharide, what happens?
The right answer is the one marked above.
A molecule of water is released.
2 C6H12O6 → C12H22O11 + H2O
Count the atoms: two glucose molecules carry 12 hydrogen and 12 oxygen between them, but the disaccharide has only 22 hydrogen and 11 oxygen. The missing H2O is what left. Run the reaction backwards — add water — and the disaccharide splits again. That is hydrolysis.