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