Where are the enzymes of the citric acid cycle primarily situated?
Відповідь
(A)
The central region of mitochondria
2
What is the first reaction in the citric acid cycle?
Відповідь
(B)
Combining acetyl-CoA with oxaloacetate
3
Which molecule acts as a catalyst in the citric acid cycle?
Відповідь
(A)
Oxaloacetate
4
Which citric acid cycle enzyme can also be found outside the mitochondria?
Відповідь
(C)
a-Ketoglutarate dehydrogenase
5
What is necessary for the α-ketoglutarate dehydrogenase enzyme to function in the citric acid cycle?
Відповідь
(A)
NAD
6
Assuming a solution contains all citric acid cycle components, excess acetyl-CoA, and is at the right pH, which factor would limit the cycle's speed?
Відповідь
(D)
Cofactor reduction
7
In the TCA cycle, what enzyme changes oxalosuccinate into α-ketoglutarate?
Відповідь
(B)
Isocitrate dehydrogenase
8
Which cofactor is essential for the enzyme -ketoglutarate dehydrogenase in the citric acid cycle?
Відповідь
(A)
Lipoate
9
In the citric acid cycle, which reaction produces a high-energy phosphate through substrate-level phosphorylation?
Відповідь
(D)
Succinyl CoA ⇌†† α-Succinate
10
Fluoroacetate prevents which reaction in the citric acid cycle?
Відповідь
(C)
Citrate ⇌†† α-cis-aconitate
11
What substance inhibits the conversion of α-Ketoglutarate into succinyl-CoA?
Відповідь
(B)
Arsenite
12
How many ATP molecules are produced in a single cycle of the citric acid cycle?
Відповідь
(B)
12
13
What is the net ATP yield from the complete oxidation of one glucose molecule?
Відповідь
(D)
38 ATP
14
Which metabolic intermediate can serve as both a starting material and an end product in glucose metabolism?
Відповідь
(A)
Lactate
15
Which of the following molecules can freely pass through the mitochondrial membrane?
Відповідь
(B)
Malate
16
Which reaction in the Kreb's cycle does not require a cofactor from the vitamin B group?
Відповідь
(A)
Citrate ‡† isocitrate
17
Which coenzyme is NOT used in the formation of acetyl-CoA from pyruvate?
Відповідь
(B)
Biotin
18
In the citric acid cycle, which molecule acts as a carrier?
Відповідь
(C)
Oxaloacetate
19
Which substance specifically inhibits succinate dehydrogenase?
Відповідь
(B)
Arsenite
20
Which enzyme in the citric acid cycle is regulated by allosteric control?
Відповідь
(C)
Fumarase
21
What is the net ATP production from the Rapport-Leubering pathway in red blood cells?
Відповідь
(A)
0
22
Under aerobic versus anaerobic conditions, what is the approximate ratio of net ATP molecules formed per glucose molecule?
Відповідь
(C)
18:1
23
Glycogen synthesis utilizes a specific nucleotide of glucose. In the following reaction, what does NuDP represent? NuDP Glucose + glycogen,→ NuDP + glycogen+1
Відповідь
(C)
UDP
24
Which describes the state of the enzyme phosphoglucomutase during the conversion of glucose 6-phosphate to glucose 1-phosphate?
Відповідь
(D)
Phosphorylated-dephosphorylatedrephosphorylated
25
Approximately what percentage of the liver's weight is glycogen?
Відповідь
(A)
6%
26
Which enzyme creates branch points during glycogenesis?
Відповідь
(A)
Amylo [1→ 4] [1→ 6] transglucosidase
27
In glycogenolysis, which enzyme facilitates the transfer of a trisaccharide unit, exposing a 1→6 branch point?
Відповідь
(B)
α-[14] α-[14] Glucan transferase
28
Which step in the synthesis of glycogen from glucose is reversible?
Відповідь
(B)
Glucose 6-phosphate glucose 1-phosphate
29
In which of the following tissues is the enzyme glucose-6-phosphatase, which converts glucose 6-phosphate to glucose, not present?
Відповідь
(B)
Muscle
30
Which molecule acts as an allosteric activator of glycogen synthase?
Відповідь
(B)
Glucose-6-Phosphate
31
Which factor suppresses the function of glycogen synthase?
Відповідь
(C)
Mg2+
32
Which hormone stimulates glycogen synthase function?
Відповідь
(A)
Insulin
33
What are the distinguishing traits of an active site?
Відповідь
(D)
Both (A) and (B)
34
A deficiency in which enzyme defines Von Gierke's disease?
Відповідь
(A)
Glucose-6-phosphatase
35
What enzyme's absence causes Cori disease (Limit dextrinosis)?
Відповідь
(B)
Debranching enzyme
36
Mc Ardle's syndrome is caused by the lack of which enzyme?
Відповідь
(B)
Muscle phosphorylase
37
Which enzyme deficiency is associated with Pompe's disease?
Відповідь
(A)
Lysosomal α-1→4 and 1→6-glucosidase
38
What enzyme deficiency results in Amylopectinosis?
Відповідь
(B)
Branching enzyme
39
What enzyme is deficient in Her's disease?
Відповідь
(B)
Liver phosphorylase
40
Tarui disease is linked to the lack of which enzyme?
Відповідь
(C)
Muscle and erythrocyte phosphofructokinase
41
Which enzyme is involved in the hexose monophosphate pathway?
Відповідь
(D)
Glucose-6-phosphate dehydrogenase
42
Which molecule accepts hydrogen in the pentose phosphate pathway?
Відповідь
(B)
NADP
43
Where are the enzymes of the pentose phosphate pathway located?
Відповідь
(A)
Cytosol
44
What enzyme converts D-ribulose-5-phosphate to D-ribose-5-phosphate in the pentose phosphate pathway?
Відповідь
(B)
Ketoisomerase
45
Which B vitamin is required by the transketolase enzyme in the pentose phosphate pathway?
Відповідь
(B)
Thiamin
46
In a reaction, Xylulose-5-phosphate donates active glycolaldehyde. Which molecule acts as the acceptor?
Відповідь
(A)
Erythrose 4-phosphate
47
What is a significant product generated by the pentose phosphate pathway?
Відповідь
(A)
NADPH for reductive synthesis
48
The pentose phosphate pathway helps protect erythrocytes from hemolysis by supporting which enzyme?
Відповідь
(C)
Glutathionic peroxidase
49
What enzyme deficiency in the pentose phosphate pathway is often associated with hemolytic anemia?
