What happens to glucose or galactose when the cu2 + in benedict's reagent is reduced?

Answer is: glucose or galactose give up an electron and they are oxidized, usually to acid.

Benedict's reagent is a mixture of sodium citrate, sodium carbonate (Na₂CO₃) and copper (II) sulfate (CuSO₄).

When Benedict's reagent is mixed and heated with glucose and galactos, the copper accept the electrons and become reduced. Benedict's test detects the presence of aldehydes in solution.