This exam has a total of 11 points. Each point corresponds to a numbered question. The numbered question is to be answered. The correct answer to a numbered question will give you one point. If the answer is partially correct, partial credit will be given as a decimal value. If the answer is incorrect, no credit will be given. If the question is unanswered, no credit will be given so it is better to guess than to leave a question blank. The number of points earned will be divided by the total number of points on the exam and multiplied by 100 to get your grade. Good luck!

In the background section the authors wrote “There is evidence that metabolism of transmitter dopamine by monoamine oxidase enzyme may promote striatal damage in mitochondrial toxin induced models of Huntington’s disease (HD) [4] “¦” Based on this and the title of this article, by what mechanism is riboflavin and pyridoxine restoring dopamine? (1 point)

How do you know that your answer to question 1 is correct? (1 point)

In the background section the authors wrote “It is known that when the activity of the enzyme Na+, K+ ATPase is inhibited, it triggers the release of excitatory amino acid in the CNS [15].” What two other things don’t happen when the activity of Na+, K+ ATPase is inhibited? (1 point)

In the measurement of dopamine (DA) section of the materials and method section the authors wrote “The DA levels were measured in the supernatant of tissue homogenized in HCIO4 after centrifugation at 5000g for 10 min in a microcentrifuge “¦” Was the supernatant of the tissue obtained from the top-middle of the centrifuge tube or from the bottom of the centrifuge tube? (1 point)

How do you know that your answer to question 4 is correct? (1 point)

In the measurement of total ATPase section of the materials and method section the authors wrote “Inorganic phosphate (Pi) was measured in triplicates using one supernatant aliquot as proposed by Flake and Subarrow [20].” Why was Pi measured to measure total ATPase? (1 point)

In the results section the authors wrote “GSH decreased in all animal groups that received the treatments however, the decrease of GSH had statistical significant difference only in those treated with Rivoflavin (B2), Rivoflavin (B2) + 3-NPA and Pyridoxine (B6) + 3-NPA when compared with the control group (Fig. 2).” What is incorrect in this statement according to Fig. 2? (1 point)

How do you know that your answer to question 7 is correct? (1 point)

In the discussion section the authors wrote “In recent studies, the dendritic spine density of striatal projection neurons was reported to be seriously decreased after 3-nitropropionic acid treatment [23]. This finding is in conformity with the results of the present study where dopamine levels increased in cortex, striatum and cerebellum/medulla oblongata regions of animals that received 3-nitropropionic acid treatment.” Why were dopamine levels not as significant in the striatum as shown in Fig. 6? (1 point)

In the discussion section the authors wrote “Calcium and magnesium-dependent ATPase activity increased in cortex, striatum, and cerebellum/medulla oblongata regions of the animals that received 3-NPA alone. This could be attributed to changes in the affinity of the enzyme [26].” What enzyme are they referring to? (1 point)

How do you know that your answer to question 10 is correct? (1 point)