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Essential Biochemistry - Nucleic Acid Metabolism (Section 3)

1
What is the primary function of the salvage pathway in nucleotide metabolism?
Answer
(C)
Recycling free bases and nucleosides to form nucleotides
2
What is the role of APRT in purine metabolism?
Answer
(B)
It is involved in the purine salvage pathway.
3
Which of the following are associated with the clinical manifestation of Lesch-Nyhan syndrome?
Answer
A
B
C
D
4
Which of the following enzymes adds a phosphate to IMP?
Answer
(D)
None of the above.
5
In the de novo synthesis of pyrimidines, which two molecules condense to form the pyrimidine ring?
Answer
(A)
Aspartate and Carbamoyl phosphate
6
Which of the following enzymes are involved in the de novo synthesis of purines?
Answer
A
B
C
7
Which of the following compounds can be used to treat gout?
Answer
(D)
All of the above
8
Which of the following is/are components of pyrimidine nucleotides?
Answer
A
B
D
9
The end products of pyrimidine catabolism include:
Answer
A
B
C
D
10
Which enzyme catalyzes the committed step in the synthesis of pyrimidine nucleotides?
Answer
(A)
Carbamoyl phosphate synthetase II
11
In the de novo synthesis of purines, which of the following compounds provide nitrogen atoms to the purine ring?
Answer
(D)
All of the above.
12
What is the initial substrate for pyrimidine synthesis?
Answer
(B)
Carbamoyl phosphate
13
Which of the following is a characteristic of primary gout?
Answer
A
B
C
14
What is the role of adenosine deaminase (ADA) in nucleotide metabolism?
Answer
(A)
It converts adenosine to inosine
15
What is the committed step in the de novo synthesis of pyrimidine nucleotides?
Answer
(A)
Formation of Carbamoyl phosphate
16
What molecule acts as a carbon donor during purine synthesis?
Answer
(B)
N10-formyltetrahydrofolate
17
Which of the following statements best describes the role of allopurinol in gout treatment?
Answer
(A)
It inhibits xanthine oxidase.
18
Which of the following is an important source of nitrogen atoms in the purine ring?
Answer
(D)
All of the above
19
Which of the following enzymes is inhibited by allopurinol?
Answer
(B)
Xanthine oxidase
20
Which enzyme catalyzes the formation of orotate?
Answer
(C)
Dihydroorotase
21
Which of the following is a substrate for orotate phosphoribosyltransferase?
Answer
(A)
Orotic acid
22
Which of the following is a symptom of Gout?
Answer
(A)
Joint inflammation
23
Which enzyme is required for the salvage pathway of purines?
Answer
(B)
HGPRT
24
What is the role of the salvage pathway?
Answer
(C)
Recycling purine bases
25
What is the first step in pyrimidine biosynthesis?
Answer
(A)
Formation of carbamoyl phosphate
26
The synthesis of which nucleotide is affected in orotic aciduria?
Answer
(C)
UMP
27
Which of the following is NOT a product of pyrimidine degradation?
Answer
(C)
Uric Acid
28
The synthesis of purine nucleotides is controlled by:
Answer
A
B
C
29
The two precursors of purine nucleotide synthesis are:
Answer
(C)
Aspartate and Glutamine
30
Which of the following enzymes is deficient in Lesch-Nyhan syndrome?
Answer
(C)
HGPRT
31
Which of the following is a characteristic feature of Von Gierke's disease in relation to purine metabolism?
Answer
(A)
Increased uric acid levels
32
Which of the following is NOT a purine nucleotide?
Answer
(C)
Cytosine
33
Which enzyme is primarily responsible for the synthesis of pyrimidine nucleotides?
Answer
(A)
Aspartate transcarbamoylase
34
Which enzyme is responsible for converting orotic acid to UMP?
Answer
(A)
Orotate phosphoribosyltransferase
35
Which of the following is the role of thymidylate synthase?
Answer
(A)
Convert dUMP to dTMP
36
Which of the following molecules is directly involved in the synthesis of purines?
Answer
(C)
Tetrahydrofolate
37
What type of genetic inheritance is observed in Lesch-Nyhan syndrome?
Answer
(C)
X-linked recessive
38
Which of the following is a symptom of Lesch-Nyhan syndrome?
Answer
(D)
All of the above
39
Which of the following is the committed step for pyrimidine synthesis?
Answer
(A)
Synthesis of carbamoyl phosphate by CPSII
40
In the salvage pathway, what molecule donates the ribose-5-phosphate group?
Answer
(A)
PRPP
41
Which of the following is true about orotic aciduria?
Answer
A
B
C
42
What is the fate of pyrimidine bases in catabolism?
Answer
(C)
Degraded to highly soluble products
43
Which of the following conditions are associated with hyperuricemia?
Answer
A
B
C
44
Which of the following is a feature of Lesch-Nyhan syndrome?
Answer
A
B
C
D
45
What is the primary treatment for Gout?
Answer
(A)
Administration of allopurinol
46
Which of the following is NOT a component of the pyrimidine ring?
Answer
(C)
Glycine
47
Which of the following enzymes is involved in pyrimidine degradation?
Answer
(C)
Dihydroorotase
48
Which of the following is a characteristic of Gout?
Answer
(A)
Increased levels of uric acid in the blood.
49
Which of the following is a characteristic of ADA deficiency?
Answer
(A)
Severe combined immune deficiency (SCID)
50
Which enzyme deficiency causes severe combined immunodeficiency (SCID)?
Answer
(C)
Adenosine deaminase