Nucleotides- Salvage pathways

Question 1

Purine Bases: adenosine phosphoribosyl transferase catalyses the reaction of a free ??? with PRPP to get an adenine nucleotide

Answer 1

a free adenine

Question 2

the deamination product of adenine is hypoxanthine which, in the salvage pathway for purines, is catalysed by hypoxanthine-guanine phosphoribosyltransferase to form ???

Answer 2

IMP

Question 3

In the salvage pathway for purines, guanine is catalysed by hypoxanthine-guanine phosphoribosyltransferase to form ???

Answer 3

GMP

Question 4

pyramidine bases salvage pathway exists in microorganisms and possibly in ???

Answer 4

mammals

Question 5

in the pyramidine salvage pathway, thymidine phosphorylase catalyses thymine to ???

Answer 5

thymidine

Question 6

Thymine is released from degraded ???

Answer 6

DNA

Question 7

in the pyrimidine salvage pathway, thymidine kinase catalyses thymadine to ???

Answer 7

TMP

Question 8

Pyrimidine salvage pathway: thymidine kinase catalyses= thymidine + ATP <–> ??? + ADP

Answer 8

TMP

Question 9

purine salvage pathway: adenosine phosphoribosyl transferase catalyse: adenine + PRPP –> ??? + PPi

Answer 9

AMP

Question 10

the anti-viral acyclovir is converted into a ??? inhibitor by viral (but not mammalian) thymidine kinase to terminate Viral DNA synthesis in herpes simplex infection

Answer 10

suicide inhibitor

Question 11

Nucleoside monophosphates (AMP) can be converted to nucleoside ??? (ADP)

Answer 11

triphosphates

Question 12

adenylate kinase phosphorylates AMP to ???

Answer 12

ADP

Question 13

ADP is phosphorylated to ATP by glycolytic enzymes or through ??? phosphorylation

Answer 13

oxidative phosphorylation

Question 14

nucleoside monophosphate kinases use ATP to form nucleoside ???
i.e ATP + NMP <–> ADP + NDP

Answer 14

diphosphates

Question 15

nucleoside diphosphate kinases convert nucleoside diphosphates to ??? i.e NTP(D) + NDP(A) <–> NDP(D) + NTP(A)

Answer 15

triphosphates

Question 16

purine degradation: produces ???

Answer 16

uric acid

Question 17

impaired adenosine deaminase (ADA) increases ??? which leads to impaired T and B lymphocyte development = primary immune deficiency

Answer 17

dATP (used in DNA synthesis)

Question 18

Defect in hypoxanthine and guanine salvage (pyrimidine salvage pathway) leads to ??? syndrome

Answer 18

lesch-nyhan

Question 19

(Purine degradation) to reduce gout, allopurinol impairs ??? oxidase by lowering the uric acid

Answer 19

xanthine oxidase

Question 20

adenosine deaminase deficiency leads to a 100x increase in ??? which is a strong inhibitor of ribonucleotide reductase = severe immunodeficiency disease

Answer 20

dATP

Question 21

in severe immunnodeficiency disease, T & B lymphocytes don’t develop properly because of a deficiency in ???

Answer 21

adenosine deaminase

Question 22

lesch-Nyhan syndrome is caused by a lack of hypoxanthine guanine phosphoribosyltransferase activity which causes an impairment of ??? and ??? salvage pathway synthesis

Answer 22

IMP and GMP

Question 23

TRUE or FALSE: lesch-Nyhan syndrome: in the absence of HPRT, PRPP and purine synthesis increases, leasing to excess uric acid and tissue damage- but not of CNS especially.

Answer 23

FALSE