Which of the following enzymes does NOT exhibit allosteric regulation?
إجابة
(C)
Succinate thiokinase
2
Which of the following is NOT a product of the citric acid cycle?
إجابة
(C)
Pyruvate
3
Which of the following citric acid cycle intermediates CANNOT be derived from amino acids?
إجابة
(C)
Malate
4
Where does the process of glycolysis take place?
إجابة
(B)
Cytosol
5
What is the final product of aerobic glycolysis?
إجابة
(C)
Pyruvate
6
Under conditions of fasting, which enzyme is primarily responsible for glucose phosphorylation?
إجابة
(A)
Hexokinase
7
Where can glucokinase be found?
إجابة
(C)
Liver
8
What is the net energy gain (in ATP equivalents) from each glucose molecule in anaerobic glycolysis?
إجابة
(A)
2 ATP equivalents
9
Which of the listed enzymes is regulated allosterically?
إجابة
(D)
Phosphofructokinase
10
In which of these locations is glycolysis anaerobic?
إجابة
(D)
Erythrocytes
11
Which substance acts as an allosteric inhibitor of phosphofructokinase?
إجابة
(D)
Citrate
12
Which molecule functions as an allosteric inhibitor for glucose-6-phosphate?
إجابة
(B)
Hexokinase
13
In the context of enzyme regulation, ATP serves as both a co-substrate and an allosteric inhibitor for which enzyme?
إجابة
(A)
Phosphofructokinase
14
The complete breakdown of a single glucose molecule into carbon dioxide and water generates approximately how many ATP molecules?
إجابة
(D)
38 ATP equivalents
15
Which unique compound is produced during glycolysis specifically in red blood cells?
إجابة
(C)
2, 3-Biphosphoglycerate
16
Which enzyme in the given list utilizes inorganic phosphate in its reaction?
إجابة
(A)
Phosphoglycerate kinase
17
The Rapoport-Luebering cycle is primarily found in which type of cells?
إجابة
(D)
Erythrocytes
18
Through which intermediate can glycerol enter the glycolytic pathway?
إجابة
(A)
Dihydroxyacetone phosphate
19
The HMP shunt metabolic pathway is present in which of the following?
إجابة
(D)
All of these
20
Which factor triggers the production of glucose-6-phosphate dehydrogenase?
إجابة
(D)
Insulin
21
In the HMP shunt, what enzyme catalyzes the decarboxylation reaction?
إجابة
(C)
6-Phosphogluconate decarboxylase
22
What is the initial pentose sugar produced during the HMP shunt?
إجابة
(B)
Ribulose-5-phosphate
23
Which enzyme plays a regulatory role in the HMP shunt?
إجابة
(C)
Both (A) and (B)
24
What factors influence the speed of the HMP shunt reactions?
إجابة
(A)
Increased by Insulin
25
Which nucleotide is essential for the process of glycogenesis?
إجابة
(C)
UTP
26
What type of bond does glycogen synthetase create?
إجابة
(A)
α-1, 4-Glycosidic bonds
27
Which hormone enhances glycogenolysis?
إجابة
(B)
Insulin
28
Which hormone primarily stimulates glycogenolysis in the liver?
إجابة
(B)
Glucagon
29
What molecule is released from glycogen by glycogen phosphorylase?
إجابة
(C)
Glucose-1-phosphate
30
Following the action of phosphorylase, what is glycogen transformed into?
إجابة
(B)
dextrin
31
In which of the following tissues is the conversion of glucose-1-phosphate to free glucose not possible?
إجابة
(C)
Muscles
32
Which of the following molecules acts as a coenzyme in phosphorylase?
إجابة
(B)
Pyridoxal phosphate
33
What is the approximate ATP equivalent energy yield if glucose-1-phosphate, produced by glycogen breakdown in muscle, is fully converted to CO₂ and H₂O?
إجابة
(B)
3 ATP equivalents
34
How many subunits comprise a single molecule of phosphorylase kinase?
إجابة
(D)
16 subunits
35
To which type of subunit does cyclic AMP bind?
إجابة
(B)
Regulatory subunits of protein kinase
36
Which of the following cell types relies exclusively on glucose for its energy needs?
إجابة
(C)
Erythrocytes
37
Where does the glycerol-3-phosphate used to create triglycerides in fat tissue originate?
إجابة
(D)
Glucose
38
In which organ does gluconeogenesis not take place?
إجابة
(C)
Muscles
39
From which of the following substances can glucose not be created?
إجابة
(D)
Leucine
40
Which molecule serves as a coenzyme for phosphoenolpyruvate carboxykinase?
إجابة
(C)
GTP
41
Which of the following is a therapeutic enzyme?
إجابة
(D)
Streptokinase and Asparaginase
42
Which enzyme facilitates gluconeogenesis?
إجابة
(C)
Phosphoenol pyruvate carboxykinase
43
What mechanisms govern the regulation of Glucose-6-phosphatase and PEP carboxy kinase?
إجابة
(C)
Induction and repression
44
What is the longest possible carbon chain length during de novo fatty acid synthesis?
إجابة
(A)
16 Carbon atoms
45
From what source is Acetyl CoA derived for new fatty acid synthesis?
إجابة
(D)
Pyruvate and related processes
46
What enzyme(s) is/are necessary for the conversion of pyruvate to acetyl CoA during fatty acid synthesis?
إجابة
(D)
All of the listed enzymes
47
Where does the primary elongation of medium-chain fatty acids occur?
إجابة
(C)
Microsomes
48
Which substance inhibits beta-oxidation of fatty acids?
إجابة
(C)
Malonyl CoA
49
Which enzyme controls fatty acid synthesis outside the mitochondria?
