Question

The electrons released during oxidation reactions cannot be captured by:

Answer 1

The electrons released during oxidation reaction can not be captured by NADPH [Nicotinamide Adenine Dinucleotide Phosphate Hydrogen].
The pentose phosphate pathway is a metabolic pathway that generates NADPH and pentoses, which are five carbon sugars. The reactions in the pathway are divided into two; oxidative and non oxidative reactions.The oxidative reactions are irreversible while the oxidative reactions are reversible. The oxidative part of the pathway result in the production of NADPH and ribulose 5 phosphate. The electrons released during this process can not be captured by NADPH. 

Answer 2

The electrons released during oxidation reactions cannot be captured by NADPH. Reactions involving electron transfers are known as oxidation-reductions. Oxiation reactions involves the loss of electrons to an electron acceptor. NADPH is the reduced form of NADP+, therefore can not be in a position to gain electrons or in other words undergo reduction process. NADPH can only act as reducing agent, meaning it can only loose electrons and therefore can not gain electrons.