Question

A reduction of NADP to $NADP{H}_2$ takes place in

• A. EMP-pathway
• B. HMP-shunt
• C. Calvin cycle
• D. Glycolysis

Answer 1

Answer: (B)

HMP-shunt

Breakdown of carbohydrates (glucose) takes place in the body by glycolysis followed by tricarboxylic acid cycle (Kreb's cycle) resulting in the energy in the form of ATP. Glucose can alternatively also undergo a different pathway to produce other products required by the cells. One of these alternate pathways is the pentose phosphate pathway or also called as hexose monophosphate pathway in which oxidation of glucose 6-phosphate takes place to produce pentoses. The fate of glucose whether to undergo glycolysis or the hexose monophosphate pathway is decided by the relative concentrations of NADP+ and NADPH. The phase starts with the oxidation of glucose 6-phosphate by the enzyme glucose 6-phosphate dehydrogenase to yield 6-phosphogluconolactone. This enzyme is an NADP dependent enzyme, where NADP+accepts an electron to form NADPH + H+.