1566 - 1607 (nucleotide metabolism)

Question 1

Identify the missing Compound X

Select one:
a. inosine monophosphate
b. inositol monophosphate
c. indole monophosphate
d. 6-oxopurine monophosphate
e. 6-oxo-5-aminopurine monophosphate

Answer 1

a. inosine monophosphate

Question 2

Identify the missing Compound X

Select one:
a. adenylosuccinate
b. succinyladenine monophosphate
c. succinylinosine monophosphate
d. 6-oxopurine monophosphate
e. 6-oxo-5-aminopurine monophosphate

Answer 2

a. adenylosuccinate

Question 3

Identify the missing Compound X

Answer 3

adenosine monophosphate

Question 4

Find out which cofactors are ‘B’ and ‘C’

Answer 4

B is NAD+, C is NADH + H+

Question 5

Indentify reactant pair ‘X’ and ‘Y’ in the reaction marked with ‘A’

Answer 5

X is glutamine, Y is glutamate.

Question 6

Examine the figure below. Identify ‘compound X’.
AMPS is adenylosuccinate, XMP is xanthosine monophosphate.

Answer 6

Inosine monophosphate

Question 7

Examine the figure below. Identify ‘compound X’.
IMP is inosine monophosphate, XMP is xanthosine monophosphate.

Answer 7

Adenylosuccinate

Question 8

Examine the figure below. Identify ‘compound X’.
IMP is inosine monophosphate, AMPS is adenlyosuccinate monophosphate.

Answer 8

Xanthosine monophosphate

Question 9

Select the correct statement below

a. AMP inhibits adenylosuccinate synthase
b. GMP stimulates IMP dehydrogenase
c. GTP inhibits adenylosuccinate synthase
d. ATP inhibits adenylosuccinate synthase
e. GTP promotes IMP dehydrogenase

Answer 9

a. AMP inhibits adenylosuccinate synthase

Question 10

Select one:
a. ATP promotes IMP dehydrogenase
b. ATP promotes transamidinase
c. AMP inhibits adenylosuccinate synthase
d. GMP inhibits IMP dehydrogenase
e. GTP promotes adenylosuccinate synthetase

Answer 10

a. ATP promotes IMP dehydrogenase

Question 11

1576 Select the false statement below:

Select one:
a. GMP stimulates IMP dehydrogenase
b. If ATP synthesis is deficient, GTP synthesis is decreased.
c. AMP inhibits adenylosuccinate synthase
d. If GTP synthesis is deficient, ATP synthesis is decreased.
e. GTP stimulates adenylosuccinate synthase

Answer 11

a. GMP stimulates IMP dehydrogenase

Question 12

Select the correct statement below:

a. GMP inhibits IMP dehydrogenase
b. If ATP synthesis is deficient, GTP synthesis is increased compensatory.
c. GTP stimulates adenylosuccinate lyase
d. If GTP synthesis is deficient, ATP synthesis is increased compensatory.
e. ATP inhibits adenylate kinase

Answer 12

a. GMP inhibits IMP dehydrogenase

Question 13

Identify ‘compound X’

Answer 13

AMP

Question 14

Identify ‘compound X’

Answer 14

GMP

Question 15

Identify ‘enzyme X’.

Answer 15

Thioredoxin reductase

Question 16

Identify ‘endproduct X’.

Answer 16

2′- Deoxyribonucleoside diphosphate

Question 17

Indentify ‘Cofactor X’ that is needed for the reaction below:

Answer 17

NADPH + H+

Question 18

What is the role of the following reaction?

a. Provides deoxyribonucleosi de diphosphates for DNA synthesis and repair.
b. Provides deoxyribonucleosi de diphosphates for DNA repair.
c. Provides deoxyribonucleoside diphosphates for DNA synthesis.
d. Provides deoxyribonucleosi de diphosphates for DNA and RNA synthesis.
e. Provides deoxyribonucleoside diphosphates for DNA and RNA repair.

Answer 18

Provides deoxyribonucleoside diphosphates for DNA synthesis and repair.

Question 19

Indentify ‘cofactor X’ that is oxidized and then reduced by the enzyme highlighted with red in the following reaction:

Answer 19

Thioredoxin

Question 20

Indentify ‘cofactor X’ that is oxidized and then reduced by the enzyme highlighted with red in the following reaction:

Answer 20

Thioredoxin

Question 21

Examine the figure below. Identify the missing enzyme ‘Enzyme X’.

a. Dihydroorotase
b. DHOA synthase
c. DHOA synthetase
d. Carbamoyl dehydratase e. CAA dehydrogenase

Answer 21

a. Dihydroorotase

Question 22

Examine the figure below. Identify the missing enzyme ‘Enzyme X’.

Answer 22

Orotidylic acid decarboxylase

Question 23

Examine the figure below. Identify the missing enzyme ‘Enzyme X’.

Answer 23

CTP synthase

Question 24

Examine the figure below. Identify the missing enzyme ‘Enzyme X’.

Answer 24

Ribonucleotide reductase

Question 25

Carbamoyl phosphate synthase II (figure below) is located in the a. cytosol b. mitochondria c. endoplasmic reticula d. peroxisome e. nucleus

Answer 25

a. cytosol

Question 26

Select the FALSE statement about the following pathway Select one: a. The pathway is located in the mitochondrial matrix b. The pathway is energetically costly. c. Several steps of the pathway are catalyzed by multifunctional proteins. d. The carbamoyl phosphate pool for urea and nucleotide synthesis is separated. e. Channeling of the intermediates of pyrimidine biosynthesis serves as a facilitator factor.

Answer 26

a. The pathway is located in the mitochondrial matrix

Question 27

Which compound is a pyrimidine analog that is an alternative substrate of Orotate phosphoribosyltransferase enzyme? a. 5-fluorouracil b. 8-Azaguanine c. 6-Thioguanine d. mycophenolic acid

Answer 27

5-fluorouracil

Question 28

Examine the figure below. Identify the missing compound 'Compound X'.

Answer 28

Carbamoyl phosphate

Question 29

Examine the figure below. Identify the missing compund 'Compound X'.

Answer 29

Orotic acid

Question 30

1595 Select the FALSE statement about the following regulation system: a. TDP promotes phosphoribosyl pyrophosphate synthesis b. CTP inhibits carbamoyl aspartic acid synthesis c. UTP inhibits phosphate synthesis d. Phosphoribosyl pyrophosphate carbamoyl synthesis

Answer 30

a. TDP promotes phosphoribosyl pyrophosphate synthesis

Question 31

Examine the figure below. Which is the factor that directly regulates 'Reaction A'? CAP is carbamoyl phosphate. Select one: a. The level of purine nucleotides. b. The level of DHOA c. The level of ATP d. The level of CTP. e. The level of TMP.

Answer 31

a. The level of purine nucleotides.

Question 32

Examine the figure below. Identify the missing 'Compound X'.

Answer 32

Adenosine

Question 33

Examine the figure below. Identify the missing 'Compound X'.

Answer 33

Inosine

Question 34

Examine the figure below. Identify the missing 'Compound X'.

Answer 34

Guanosine

Question 35

Examine the figure below. Identify the missing 'Compound X'.

Answer 35

Hypoxanthine

Question 36

Examine the figure below. Identify the missing 'Compound X'.

Answer 36

Guanine

Question 37

Examine the figure below. Identify the missing 'Compound X'.

Answer 37

Xanthine

Question 38

Examine the figure below. Identify the missing 'Compound X'.

Answer 38

Uric acid

Question 39

Examine the figure below. Identify the missing 'Enzyme X'.

Answer 39

Adenosine deaminase

Question 40

Examine the figure below. Identify the missing 'Enzyme X'.

Answer 40

Purine nucleoside phosphorylase

Question 41

Examine the figure below. Identify the missing 'Enzyme X'.

Answer 41

Xanthine oxidase

Question 42

1607 Examine the figure below. Which statment is TRUE about the biosynthesis of purine and pyrimidine nucleotides? a. ATP stimulates 2'dCTP synthesis b. ATP inhibits 2'UDP synthesis c. 2'dTTP exerts a positive feedback for its own synthesis d. 2'GTP inhibits the synthesis of 2'dADP

Answer 42

a. ATP stimulates 2'dCTP synthesis