Download QUIZ #7 NUCLEOTIDE METABOLISM

QUIZ #7
170.
NUCLEOTIDE METABOLISM
Which of the following is used during the conversion of uracil to thymine?
a. SAM
b. THF
c. THB
d. Biotin
e. CO2
171.
The nitrogens of a purine molecule are derived from all of the following amino acids EXCEPT:
a. Aspartic Acid
b. Asparagine
c. Glutamine
d. Glycine
172.
What is the correct sequence of appearance of intermediates in the degradation of adenosine?
a. Adenosine --> hypoxanthine -->xanthine --> inosine --> uric acid
b. Adenosine --> inosine --> hypoxanthine --> xanthine --> uric acid
c. Adenosine --> xanthine --> hypoxanthine --> inosine --> uric acid
d. none of the above are correct
173.
Which of the following is NOT utilized in the the conversion of ribose to deoxyribose?
a. NADPH
b. FADH2
c. UMP
d. Thioredoxin
e. Ribonucleotide reductase
174.
GLN-PRPP amidotransferase is inhibited by:
a. High [PRPP]
b. High [NMP], [NDP] and [NTP]
c. Insulin
d. Glucose
175.
Phosphoribosyl pyrophosphate is:
a. Formed during a regulated step in purine synthesis
b. Formed by the action of phosphoribosyl synthetase
c. A substrate for both purine and pyrimidine biosynthesis
d. Hydrolyzed by the action of inorganic pyrophosphate phosphatase
e. 1), 2) and 3) are correct
176.
During nucleotide biosynthesis, which of the following contribute to the structure of BOTH purines and
pyrimidines?
a. Aspartic acid
b. Methylene-THF
c. Glutamine
d. Glycine
e. 1), 2) and 3) are correct
177.
Which of the following is NOT a nucleoside?
a. Adenosine
b. Cytidine
c. Cytosine
d. Guanosine
e. Uridine
178.
Which of the following bases is least likely to appear as a nucleotide?
a. AMP
b. d-ADP
c. d-GTP
d. d-UMP
e. Thymidylic acid
179.
GTP inhibits which of the following reactions in purine biosynthesis?
a. PRPP --> PRNH2
b. IMP --> GMP
c. IMP --> AMP
d. 1) and 2) are correct
e. 1), 2) and 3) are correct
180.
Carbamoyl phosphate synthetase II (CPS-II) is:
a. Activated by PRPP
b. Inhibited by UMP
c. Activated by ATP
d. The key committed step in the formation of carbamoyl~phosphate
e. All of the above are correct
181.
Complete this analogy:
NOR-EPINEPHRINE : EPINEPHRINE as URACIL : ?
a. Cytosine
b. Hypoxanthine
c. Xanthine
d. Thymine
e. Orotic Acid
182.
Methotrexate inhibits:
a. ribonucleotide reductase
b. thymidylate synthase
c. dihydrofolate reductase
d. PRPP-amidotransferase
e. HX/G-phosphoribosyl transferase
183.
G/HX phosphoribosyl transferase:
a. is utilized in the synthesis of the purine ring
b. is required for the salvage of purine bases
c. converts hypoxanthine to guanine
d. is inhibited by methotrexate
e. is required to convert purines to uric acid