Quick Biochemistry - Nucleic Acids (Section 5)
1
Which of the following enzymes is not inhibited by GMP through allosteric regulation?
إجابة(D)
Adenylosuccinate synthetase
2
AMP inhibits which of the following through allosteric regulation?
3
Which enzyme catalyzes the initial distinctive reaction in purine nucleotide synthesis?
إجابة(B)
PRPP glutamyl amido transferase
4
What are the free purine bases that can be repurposed through salvage pathways?
إجابة(D)
Adenine, guanine and hypoxanthine
5
Which enzyme is essential for the recycling of free purine bases?
6
Which of the following molecules can be salvaged by deoxycytidine kinase?
7
Which molecule(s) can be salvaged by adenosine kinase?
إجابة(B)
Adenosine and deoxyadenosine
8
The salvage of purine bases is primarily regulated by which factor?
9
When PRPP is available, what process is favored?
10
What is the final product of purine breakdown in the human body?
11
Which enzyme is involved in the breakdown of all purines?
إجابة(B)
Purine nucleoside phosphorylase
12
In which organism is uric acid the final product of both purine and protein breakdown?
13
What is the typical daily uric acid excretion range for adult males?
14
Where does the breakdown of purines from food primarily occur?
15
In which cellular compartment does the de novo synthesis of pyrimidine nucleotides take place?
16
Which enzyme is used in the creation of new pyrimidine nucleotides and also participates in urea synthesis?
إجابة(B)
Carbamoyl phosphate synthetase
17
What substances supply the nitrogen atoms required to build a pyrimidine nucleus?
18
From what sources do the carbon atoms in a pyrimidine nucleus originate?
19
Which molecule provides the nitrogen atom at position 1 in the pyrimidine ring?
20
Which molecule provides the nitrogen atom at position 3 in the pyrimidine ring?
21
Which of the following molecules provides the carbon atom at position 2 of the pyrimidine nucleus?
22
From the following options, which carbon atoms of the pyrimidine nucleus are contributed by Aspartate?
23
In the de novo synthesis pathway, which pyrimidine nucleotide is generated first?
24
The conversion of uridine diphosphate to deoxyuridine diphosphate necessitates the use of all the following, except
25
The synthesis of which of the following molecules is reduced by Amethopterin and aminopterin?
26
Where does the amino group for the synthesis of CTP and UTP originate?
27
What are the substrates for the CTP synthetase reaction that forms CTP?
28
What coenzyme is essential for the synthesis of TMP from dump?
إجابة(C)
N5, N10- Methylene tetrahydrofolate
29
Excluding which of the following, all enzymes involved in the de novo synthesis of pyrimidine nucleotides are found in the cytosol?
إجابة(D)
Dihydro-orotate dehydrogenase
30
In the de novo synthesis of pyrimidine nucleotides, what is the first ring compound formed?
31
Tetrahydrofolate plays a crucial role as a coenzyme in the production of which molecule?
32
Which statement regarding thioredoxin reductase is incorrect?
إجابة(A)
It utilizes NADH as a coenzyme
33
Which enzyme is responsible for regulating the initial synthesis of pyrimidine nucleotides?
34
Which molecule inhibits cytosolic carbamoyl phosphate synthetase?
35
Which molecule activates cytosolic carbamoyl phosphate synthetase?
36
Which molecule inhibits the activity of Aspartate transcarbamoylase?
37
Which of the following compounds cannot be recycled in human metabolic processes?
38
From which molecule is B-Aminoisobytyrate produced during breakdown?
39
During the breakdown of which molecule(s) is free ammonia released?
40
B-Alanine is a product of the catabolism of which combination of molecules?
41
Which coenzyme is essential for the breakdown of pyrimidine bases?
42
What is the mode of inheritance for primary gout?
43
Which alteration in PRPP synthetase can lead to primary gout?
44
Which statement about primary gout is not accurate?
إجابة(C)
It can be due to increased activity of hypoxanthine guanine phosphoribosyl transferase
45
Which of the following statements regarding uric acid is false?
إجابة(C)
It is not dissociated at a pH above 5.8
46
In a genetic deficiency of hypoxanthine guanine phosphoribosyl transferase, what happens?
إجابة(B)
Salvage of purines is decreased
47
Which statement about uric acid is incorrect?
إجابة(A)
It can be produced from allantoin
48
Which of the following is NOT a characteristic of primary gout?
إجابة(C)
Urinary excretion of uric acid is reduced
49
Which of the following is NOT a characteristic of allopurinol?
إجابة(A)
It is a structural analogue of uric acid
50
How is orotic aciduria managed?
إجابة(D)
Oral administration of uridine
