Biochemistry - Folic Acid and B12-Questions and Answers Graded A+

Biochemistry - Folic Acid and B12-Questions and Answers Graded A+ What are dietary sources of Vitamin B12? - ANSWER-Meats Shellfish Poultry Eggs Dairy products Which two reactions require Vitamin B12? - ANSWER-Homocysteine -> Methoinine (homocysteine N-methyltransferase/methionine synthase) Isomerization of methyl malonyl CoA (methylmalonyl-CoA mutase) What are the two reactions that require S-Adenosylmethionine (SAM)? - ANSWER-Norepinephrine -> Epinephrine Homocysteine -> Methionine What are the two products that can be formed by L-homocysteine? - ANSWER-L-Methionine L-Cysteine What effect does a B12 deficiency have on THF? - ANSWER-Stuck in methyl form Which three enzyme deficiencies can lead to homocystinuria? - ANSWER-Folate (B9) Vitamin B12 Vitamin B6 What causes pernicious anemia? - ANSWER-Lack of intrinsic factor due to autoimmune destruction of parietal cells. B12 can't be transported to intestines. What do you use to treat megaloblastic anemia? - ANSWER-Folate (B9) and vitamin B12 What are some conditions that can lead to a B12 deficiency? - ANSWER-Pure vegan diet Chronic pancreatitis Terminal ileal disease What are some symptoms associated with hyperhomocysteinemia? - ANSWER-Lens dislocation Osteoporosis Lipid deposits/atheromas Fibrosis How is taurine formed? - ANSWER-Cysteine + cysteine dioxygenase What are some dietary sources of Folic Acid (B9)? - ANSWER-Green, leafy vegetables Liver Lima beans Whole-grain cereals What are some important reactions that require THF? - ANSWER-DNA and RNA synthesis Glycine <--> Serine