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