Vitamin B12 Deficiency and Metabolism

This video tutorial explores the significance of Vitamin B12, focusing on its role in two key enzymes: homocysteine methyl transferase and methylmalonyl-CoA mutase. It discusses the dietary sources and absorption process of Vitamin B12, and delves into the biochemical pathways involving these enzymes. The tutorial highlights the importance of Vitamin B12 in DNA synthesis, energy metabolism, and the prevention of neurological damage. It also addresses the consequences of Vitamin B12 deficiency, such as macrocytic anemia and neuropathy.

Which of the following is NOT a dietary source of Vitamin B12?

• Meat

• Fish

• Dairy

• Fruits

What is the primary function of homocysteine methyl transferase?

• Converts methylmalonyl-CoA to succinyl-CoA

• Converts succinyl-CoA to methylmalonyl-CoA

• Converts methionine to homocysteine

• Converts homocysteine to methionine

Which compound is regenerated during the conversion of homocysteine to methionine?

• Succinyl-CoA

• Methylmalonic acid

• Propionyl-CoA

• Tetrahydrofolate

What condition is associated with a deficiency in Vitamin B12 affecting homocysteine methyl transferase?

• Microcytic anemia

• Aplastic anemia

• Macrocytic anemia

• Hemolytic anemia

Which of the following is a symptom of Vitamin B12 deficiency related to DNA synthesis?

• Hypersegmented neutrophils

• Increased red blood cell count

• Decreased white blood cell count

• Increased platelet count

What is the role of methylmalonyl-CoA mutase in the body?

• Converts methylmalonyl-CoA to succinyl-CoA

• Converts succinyl-CoA to methylmalonyl-CoA

• Converts methionine to homocysteine

• Converts homocysteine to methionine

Which cycle is succinyl-CoA a part of?

• Urea cycle

• Krebs cycle

• Pentose phosphate pathway

• Glycolysis

What toxic intermediate builds up due to Vitamin B12 deficiency affecting methylmalonyl-CoA mutase?

• Methylmalonic acid

• Tetrahydrofolate

• Methionine

• Homocysteine

Which part of the nervous system is affected by the buildup of methylmalonic acid?

• Cerebral cortex

• Dorsal column medial lemniscus system

• Cerebellum

• Basal ganglia

What neurological symptom is associated with Vitamin B12 deficiency?

• Decreased muscle tone

• Increased reflexes

• Symmetric paresthesias

• Asymmetric paresthesias