26malik
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Folate plays a role in single-carbon unit transfer in the synthesis of nucleotides. Which of the following nucleotides require folate for synthesis?
A. Adenosine, cytosine, and uracil
B. Adenosine, guanine, and thymidine
C. Adenosine, guanine, and uracil
D. Cytosine, thymidine, and uracil
E. Guanine, thymidine, and uracil
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| robin082006
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D
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| robin082006
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sorry, I go with B now
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| general malaise
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B?
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| leen
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seems like D 
wats the right ans?
thanks
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| mjl1717
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must be pyrimidines synthesis so its answer d.
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| general malaise
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answer malik?
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| robin082006
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B
A, G and T for sure
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| DocPakMan
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Im gonna go with D., isnt folate important for the methyl group in pyrimidines?
whats the final "Correct" answer?
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| humpf!!
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i think the answer is B. Here's why I think so:
De Novo Purine Synthesis (A and G):
Ribose 5P -> PPRP ->->->(THF)-> IMP -> GMP and AMP
De Novo Pyrimidine Synthesis (C, U, and T):
Glutamine ->->-> Orotic Acid ->->-> UMP -> CTP and dUDP ->(THF)->dTMP
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| 26malik
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The correct answer is B.
Folate is involved in the transfer of carbons 2 and 8 of the purine nucleus(affecting adenosine and guanosine) and the 5-methyl group of thymidine. This means that folate is required for synthesis of 3 of the 4 nucleic acid bases of DNA and 2 of the 4 nucleic acid bases in RNA. It is thus no wonder that folate deficiency has effects on so many tissues with high mitotic rate. Megaloblastic changes analogous to those seen in erythrocytes and their precursors can also be seen in other cells produced by bone marrow (neutrophil, eosinophil, basophil, and macrophage as well as megakaryocyte lines) and in epithelia throughout the body, including skin, mucous membranes such as the mouth and vagina (where the changes can be seen on Pap smear), stomach and intestinal linings, and cells from lung or liver. Similar megaloblastic changes are observed throughout the body when cobalamin (vitamin B12) deficiency is present, since cobalamin plays a role in methionine synthesis, which is the source of the one-carbon unit "active-formate." Cobalamin is also involved in the conversion of methylmalonic acid to succinic acid and is required to maintain the integrity of nerve cells via an unknown biochemical pathway.
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| 26malik
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sorry guys for late post as there was a problem with my modem 
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| DocPakMan
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I thought I would take a stab at it cuz I just finished my 1st read on the topic!! but thanks for the answer.....
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