Question

In pentose phosphate shunt, the number of NADPH formed per glucose molecule is
(a) 12
(b) 6
(c) 2
(d) 10

Answer 1

The method of oxidation of glucose or the tricarboxylic acid cycle is called the Pentose monophosphate shunt. Six hexose monophosphate shunting glucose molecules contain $NADP{ H }_{ 2 }$ and 6 carbon dioxide. 3ATP generates one $NADP{ H }_{ 2 }$.
Complete step by step answer**
The pentose phosphate shunt is also known as the hexose monophosphate shunt. This process occurs in the cell cytoplasm and it divides into two parts: the oxidative and non-oxidative stages. This is the only process that generates reduced $NADP{ H }_{ 2 }$ which acts in the biosynthetic processes as the reduction agent. The number of NADPH formed per glucose molecule is 12 in number. These 12 molecules of $NADP{ H }_{ 2 }$ form 36 ATP molecules while undergoing ETS. In the beginning, one ATP is consumed which results in the net formation of 35 ATP molecules. Two molecules of $NAD{ P }^{ + }$ are reduced to NADPH in the oxidative step, using the energy from converting glucose-6-phosphate into ribulose-5-phosphate. These NADPH molecules are used as the source of energy by the cells.
Importance of NADPH produced from the HMP shunt:
-Free radical scavenging
-Erythrocyte membrane integrity
-Prevention of Met-hemoglobinemia
-Detoxification of drugs
-For the transparency of the eye lens.
-Macrophage bactericidal activity

So, the correct answer is ‘12’.

Note:
The HMP shunt pathway is under the regulation of the stress of NADPH within the respective tissue. NADPH is a strong inhibitor of glucose 6-phosphate dehydrogenase whereas NADPH is used in the various pathways, inhibition is relieved and the enzyme is accelerated to produce more NADPH. The entry of glucose 6-phosphate into the HMP pathway is controlled by the cellular concentration of NADPH.