Thiamine (vitamin B1) deficiency diseases have a lower prevalence now than in the past. However, they are seen as beriberi in some developing regions and in regions of crisis, and as Wernicke-Korsakoff syndrome in some alcoholics. One type of beriberi causes neurological symptoms such as weakness, fatigue, and loss of sensations. What is a possible explanation for these symptoms? Thiamine is necessary for gluconeogenesis. Hexokinase requires thiamine. Coenzymes of the pentose phosphate pathway require thiamine as a precursor. Thiamine is a precursor to the cofactor for succinyl coenzyme A synthetase. The brain uses glucose, metabolized in glycolysis and the citric acid cycle, as its main energy source.

The correct answer is coenzymes for the pentose phosphate pathway require thiamine as a precursor.The brain uses glucose metabolized in glycolysis and citric acid cycle as its main source of energy.

Explanation:

Thiamine is the chemical name of vitamin B1.Thiamine is used as co enzymes in form of thiamine pyro phosphate.

An enzyme of pentose phosphate pathway known as transketolase uses TPP as a coenzyme.As a result due to te deficiency of Thiamine pentose phosphate pathway is hampered.

On the other hand TPP is an important coenzyme of pyruvate dehydrogenase enzyme complex which catalyses the conversion of pyruvate into acetyl CoA.

Due to defeciency of Thiamine the acttivity of pyruvate dehydrogenase enzyme system is somehow hampered .As a result glucose cannot be completely metabolized into CO2 and H2O.

Therefore brain cannot function normally because brain depends on glucose as the principle source of energy.