A rapidly dividing cell will have a greater abundance of which nucleotide?
Guanine and Adenine because purine synthesis is more important for a developing cell
Cytosine and Thiamine because pyrimidine synthesis is less taxing and therefore proceed more quickly
The concentration of pyrimidines and purines will be equal regardless of the conditions
Purines are critical for DNA replication, so purine concentration will be higher
Which of the following is a nucleotide?
For the previous question why was the correct answer the only nucleotide?
It was the only answer that consisted of a nucleoside bound to a phosphate group
All of the other answers were sugars
All of the other answers were bases
None of the other answers were biologically important molecules
Which of the following is not a biological function of Nucleotides?
They are precursors to glycogen and other phosphoglycerides
Nucleotides exclusively compromise the universal energy currency
They serve as metabolic regulators and mediate the action of many hormones
Nucleotides entirely make up three major co-enzymes: NADH, FAD, and CoA
cAMP is a nucleotide that mediates hormones
Purine biosynthesis involves which of the following precursors?
All of the above are required atom contributors
PRPP (Phosphoribosylpyrophosphate) is the source of the ribose sugar in...
purine de novo synthesis and purine salvage pathways
purine de novo synthesis
purine and pyrimidine de novo synthesis
Which describes the committed step for purine de novo synthesis?
Glutamine-PRPP amido-transferase is the active enzyme
PRPP feeds into the committed step
Glutamine feeds into the step and becomes glutamate
All of the above
THF is an enzyme that performs which of the following actions?
Eliminates an amide group
Transfers one carbon from N10-Formyl THF to the growing purine precursor
Allosterically activates HGRPT
Facilitates a Glutamine dependent nitrogen tranfer
Facilitates ring closure of the growing purine
The base hypoxanthine is described by which of the following statements?
Inosinic Acid (IMP) is the nucleoside form of hypoxanthine
Hypoxanthine is critical only to the conversion of IMP to GMP not IMP to AMP
Hypoxanthine is reduced to xanthine during the purine synthesis pathway
The oxidation of hypoxanthine to xanthine is blocked by allpurinol
PRPP impacts which of the following?
De novo synthesis of purines
Direct production of IMP through PRPP's reaction with Hypoxanthine
Direct production of GMP through PRPP's reaction with Guanine
All of the above are catalyzed by HGPRT and all are true in healthy cells
Which of the following is deficient in Gout?
ADA (adenosine deaminase)
PNP (purine nucleoside phosphorylase)
You have to be more specific, gout could be the result of numerous enzyme deficiencies
XO (xanthine oxidase)
Lesch Nyhan Syndrome is caused by a deficiency in which of the following?
You have to provide more information, Lesch Nyhan Syndrome could be caused by the deficiency of a number of different enzymes
Which is the committed step of Pyrimidine synthesis?
Aspartate Transcarbamoylase ATCase
Familial Orotic Aciduria can be treated using which of the following methods?
There is no curative treatment, simply a management of symptoms
Delivery of large doses of orally administered uridine to simply bypass the early steps of pyrimidine synthesis
Delivery of large doses of the missing/deficient orotate phosphoribosyltransferase (OPRT)
Delivery of fully synthesized pyrimidines for uptake into the cell
Which of the following are made by a two enzyme complex (Thymidylate Synthetase and Dihydrofolate reductase) after ribonucleotide reductase acts on freshly minted purines and pyrimidines?
dATP is the master negative regulator of Ribonucleotide Reductase.
Which of the following enzymes should I know really well?
Amidophosphoryl Transferase ATase = glutamine PRPP amidotransferase
I should probably know all of these
Why do we use "De Novo" instead of saying from scratch?
Because Carl Sagan's famous Apple Pie from scratch comment makes it too awesome to use in any setting other than musing about the universe
Because De Novo is more descriptive
To confuse those who are sadly lacking in medical jargon
Because fancy language is awesome