Lippincott - Nucleotide Metabolism

Question 1

composition of nucleoside

Answer 1

pentose sugar + base

Question 2

composition of nucleotide

Answer 2

nucleoside + 1 or more phosphate groups

Question 3

deoxyribose sugars are formed by removing the oxygen associated with which carbon of a ribose sugar?

Answer 3

2nd carbon

Question 4

nitrogens of purine rings come from:

Answer 4

[1] glycine
[2] glutamine
[3] aspartate

Question 5

carbons of purine rings come from:

Answer 5

[1] glycine
[2] carbon dioxide
[3] N-formyl-tetrahydrofolate

Question 6

organ where purine rings are synthesized

Answer 6

liver

Question 7

activated pentose that is a major part of purine and pyrimidine biosynthesis

Answer 7

PRPP

Question 8

committed step in de novo synthesis of purines

Answer 8

synthesis of 5’ phosphoribosylamine from PRPP and glutamine

Question 9

parent purine nucleotide

Answer 9

inosine monophosphate

Question 10

energy requirement for conversion of IMP to GMP

Answer 10

ATP

Question 11

energy requirement for conversion of IMP to AMP

Answer 11

GTP

Question 12

responsible for synthesis of nucleoside diphosphates

Answer 12

base specific nucleoside monophosphate kinase (adenylate kinase, guanylate kinase, etc)

Question 13

responsible for synthesis of nucleoside triphosphates

Answer 13

nonspecific nucleoside diphosphate kinase

Question 14

enzymes involved in salvage pathway for purines

Answer 14

[1] adenine phosphoribosyltransferase (APRT)

[2] hypoxanthine-guanine phosphoribosyltransferase (HGPRT)

Question 15

salvage pathway for purines - hypoxanthine is converted to:

Answer 15

IMP

Question 16

salvage pathway for purines - guanine is converted to:

Answer 16

GMP

Question 17

salvage pathway for purines - adenine is converted to

Answer 17

AMP

Question 18

Lesch-Nyhan syndrome

Answer 18

x linked recessive disorder associated with complete deficiency of HGPRT –> inability to salvage hypoxanthine or guanine –> high uric acid due to excessive degradation

Question 19

responsible for deoxyribonucleotide synthesis from ribonucleotides

Answer 19

ribonucleotide reductase

Question 20

inhibitor of ribonucleotide reductase

Answer 20

dATP binding to allosteric sites

Question 21

organ of degradation of purine nucleotides

Answer 21

liver

Question 22

end product of purine degradation

Answer 22

uric acid

Question 23

hydrolyze dietary DNA

Answer 23

deoxyribonucleases

Question 24

hydrolyze dietary RNA

Answer 24

ribonucleases

Question 25

product of DNA/RNA hydrolysis

Answer 25

oligonucleotides

Question 26

hydrolyze oligonucleotides

Answer 26

pancreatic phosphodiesterases

Question 27

responsible for removing phosphate groups from nucleotides

Answer 27

nucleotidases

Question 28

carbons of pyrimidine come from;

Answer 28

[1] aspartic acid

[2] carbon dioxide

Question 29

nitrogens of pyrimidine come from:

Answer 29

[1] R group of glutamine

[2] aspartic acid

Question 30

regulated step in de novo pyrimidine synthesis

Answer 30

synthesis of carbamoyl phosphate from glutamine and carbon dioxide

Question 31

catalyzes regulated step in de novo pyrimidine synthesis

Answer 31

carbamoyl phosphate synthetase II

Question 32

inhibit CPS II

Answer 32

UTP

Question 33

activate CPS II

Answer 33

PRPP

Question 34

difference of CPS I and CPS II

Answer 34

CPS I is used in the urea cycle, CPS II is used in de novo pyrimidine synthesis

Question 35

main enzymes in orotic acid synthesis

Answer 35

CAD
[1] CPS II
[2] aspartate transcarbamolyase
[3] dihydroorotase

Question 36

major intermediate in de novo pyrimidine synthesis

Answer 36

UMP

Question 37

how is CTP synthesized from UTP?

Answer 37

amination of UTP by CTP synthetase

Question 38

responsible for CTP synthesis from UTP

Answer 38

CTP synthetase

Question 39

responsible for TMP synthesis from dUMP

Answer 39

thymidylate synthase

Question 40

source of the methyl group in TMP synthesis

Answer 40

N5N10 methylene tetrahydrofolate

Question 41

end products of pyrimidine degradation

Answer 41

[1] beta alanine
[2] beta aminoisobutyrate
[3] NH3
[4] CO2

Question 42

[T/F] pyrimidines are more frequently salvaged in human cells compared to purines

Answer 42

F