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