NUCLEIC ACIDS

Question 1

what are ribonucleotides used for?

Answer 1

energy transport (ATP,GTP)
producing 2nd messengers (cAMP, cGMP)
producing para/autocrines (adenosine)
components of cofactors (NAD+, NADP+)
RNA synthesis (ATP, GTP, CTP,UTP)

Question 2

for ribose, where is the -OH group located?

Answer 2

the second carbon

Question 3

what converts ribose 5-phosphate to 5-phospho-alpha,D-Ribose-1-pyrophospahte (PRPP)?

Answer 3

ribosephosphate pyrophosphokinase

Question 4

this key regulatory enzyme commits ribose to be made into nucleotides or deoxynucleotides?

Answer 4

ribosephosphate pyrophosphokinase

Question 5

what is PRPP a precursor to?

Answer 5

purine and pyrimidine nucleotides

Question 6

in the synthesis toward a purine, PRPP is converted to glutamate by what enzyme?

Answer 6

amidophosphoribosyl transferase

Question 7

in the synthesis toward a pyrimidine, you take an aspartate and carbamoyl phosphate to produce orotic acid to produce orotidylate via what enzyme?

Answer 7

orotidylate pyrophosphorylase

Question 8

what drug interferes with purine synthesis?

Answer 8

sulfonamides, methotrexate both antimicrobial drugs

Question 9

aspartate and carbamoyl phosphate are made into orotic acid via what enzyme? this is key for pyrimidine synthesis

Answer 9

aspartate transcarbamylase

Question 10

what is the key enzyme regulating how much prpp becomes purine nucleotides?

Answer 10

amidophosphoribosyl transferase

Question 11

this is a glutamine analog which is antibacterial by blocking purine synthesis?

Answer 11

azaserine

Question 12

so when we have IMP, and we need to synthesize GTP what is used to produce the GMP from XMP?

Answer 12

ATP and GMP synthase

Question 13

so when we have IMP, and we need to synthesize ATP what is used to produce the adenylosuccinate from IMP?

Answer 13

GTP and adenylosuccinate synthetase

Question 14

what is needed make GMP and AMP?

Answer 14

ATP is needed to make GMP, GTP is needed to make AMP

Question 15

what inhibits orotic acid synthesis and pyrimidines?

Answer 15

CTP

Question 16

UDP and CDP are used to make what?

Answer 16

dCTP and dTTP for RNA synthesis, whereas UTP and CTP are used for RNA synthesis

Question 17

in the synthesis of deoxyribonucleotide from ribonucleotide, what is used?

Answer 17

ribonucleotide reductase and thioredoxin

Question 18

thioredoxin is reoxidized by what enzyme?

Answer 18

thioredoxin reductase with NADH

Question 19

what is the product of AMP catabolism?

Answer 19

hypoxanthine

Question 20

this is more soluble, so it its less likely to precipitate and so it is removed from the body as uric acid?

Answer 20

xanthine

Question 21

this is the primary waste product of purine catabolism?

Answer 21

uric acid

Question 22

what is used to treat gout?

Answer 22

allopurinol, this inhibits xanthine oxidase

Question 23

how does Lesch-Nyhan syndrome occur?

Answer 23

if GPRTase or HGPRT is missing then salvage is inhibited and this disease results, so aggression occurs, kidney stones, renal failure and self mutilation.

Question 24

what are the waste products of pyrimidine catabolism?

Answer 24

malonate(cytosine) and methylmalonate(thymine)