Purine and Pyrimidine Metabolism

Question 1

PRPP synthetase converts

Answer 1

Ribose 5-P to PRPP

Question 2

Pyrimidines are synthesized de novo in cytoplasm from

Answer 2

Aspartate

CO₂

Glutamine

Question 3

Orotic aciduria genetics

Answer 3

AR

Question 4

Orotic aciduria is due to a defect of

Answer 4

Uridine monophosphate synthase

Question 5

Carbamoyl phosphate synthetase 2 converts

Answer 5

CO₂ + glutamine + ATP to Carbamoyl phosphate in De Novo pyrimidine synthesis

Question 6

UMP synthase converts

Answer 6

Orotic acid to UMP with the addition of PRPP

Question 7

Ribonucleotide reductase converts

Answer 7

UDP to dUDP and CTP

Question 8

What inhibits Ribonucleotide reductase

Answer 8

Hydroxyurea

Question 9

Thymidylate synthase converts

Answer 9

dUMP to dTMP with THF

Question 10

What inhibits Thymidylate synthase

Answer 10

5-FU

Question 11

What inhibits dihydrofolate reductase

Answer 11

1. Methotrexate
2. Trimethoprim
3. Pyrimethamine

Question 12

What is the most important enzyme in Purine de novo synthesis

Answer 12

PRPP amidotransferase

Question 13

PRPP synthetase converts

Answer 13

Ribose 5-P to PRPP in De Novo purine synthesis

Question 14

PRPP amidotransferase converts

Answer 14

PRPP to 5-Phosphoribosylamine in De novo purine synthesis

Question 15

What inhibits PRPP amidotransferase

Answer 15

1. AMP
2. IMP
3. GMP
4. Allopurinal nucleotide
5. 6-MP

Question 16

Adenosine deaminase converts

Answer 16

Adenosine to Inosine in Purine excretion and salvage pathway

Question 17

Purine nucleoside phosphorylase converts

Answer 17

Insoine to Hypoxanthine in purine exretion and salvage pathway

Question 18

HGPRT converts

Answer 18

Hypoxanthine to IMP and GMP in Purine salvage pathway

Question 19

Lesch-Nyhan syndrome is a deficiency in

Answer 19

HGPRT

Question 20

Lesch-Nyhan syndrome symptoms

Answer 20

1. Spastic cerebral palsy
2. Self mutliation
3. Hyperuricemia

Question 21

Lesch-Nyhan syndrome genetics

Answer 21

X-linked recessive