Briefly discuss why each of the three common forms of galactosemia involves impaired utilization of galactose. part a which metabolic process is blocked in each condition?

1. Each of three common form of galactosemia involved impaired utilization of glucose because certain enzymes which are very important to galactose metabolism are absent. The absence of these enzymes prevents the body from properly metabolism galactose, thus, the sugar is found in the blood at high concentration.

2. Galactosemia is a disorder which affects how the body processes a sugar called galactose. In this disorder, too much galactose is found in the blood. There are three major forms of galactosemia, these are:

1. Type 1 galactosemia {Classic galactosemia} is the most severe form of this disease. It is an inborn error of galactose metabolism, which is caused by the deficiency of the enzyme galactose 1 phosphate uridylyltransferase. Thus, the reaction catalyzed by this enzyme is blocked in this disorder.

2. Type 2 galactosemia is an autosomal recessive metabolic disorder, that is marked by accumulation of galactose and galactitol. The enzyme that is deficient in this disroder is galactokinase. The chemical reaction catalyzed by this enzyme is blocked in this disorder.

3. Type 3 galactosemia is a rare autosomal recessive form of galactosemia, which is associated with the deficiency of the enzyme galactose epimerase. Thus, in this disorder, the biochemical reaction, which is catalyzed by galactose epimerase is blocked.