Questão 1
Questão
Where does the TCA cycle take place?
Responda
-
Mitochondrial matrix
-
Cytosol
-
Endoplasmic reticulum
-
Golgi apparatus
Questão 2
Questão
The TCA cycle takes place in all tissues.
Questão 3
Questão
Fill in the blanks below to give a general description of the TCA cycle.
1. [blank_start]Acetyl CoA[blank_end] (2C) combines with [blank_start]oxaloacetate[blank_end] (4C) to form [blank_start]citrate[blank_end] (6C).
2. [blank_start]Citrate[blank_end] is isomerised to [blank_start]isocitrate[blank_end] (6C).
3. Citrate is decarboxylised to [blank_start]a-ketoglutarate[blank_end] (5C)
4. [blank_start]a-ketoglutarate[blank_end] is decarboxylised to [blank_start]succinyl-CoA[blank_end] (4C)
5. [blank_start]Succinyl CoA[blank_end] is converted to [blank_start]succinate[blank_end], then [blank_start]fumarate[blank_end], then [blank_start]malate[blank_end], then finally back to [blank_start]oxaloacetate[blank_end].
6. The cycle repeats.
Responda
-
Acetyl CoA
-
oxaloacetate
-
citrate
-
Citrate
-
isocitrate
-
a-ketoglutarate
-
succinyl-CoA
-
a-ketoglutarate
-
Succinyl CoA
-
succinate
-
fumarate
-
malate
-
oxaloacetate
Questão 4
Questão
Which enzyme carries out the link reaction?
Responda
-
Pyruvate dehydrogenase
-
Lactate dehydrogenase
-
Pyruvate decarboxylase
-
Acetyl CoA synthase
Questão 5
Questão
Fill in the blanks below to describe the link reaction.
P[blank_start]yruvate[blank_end] reacts with c[blank_start]oenzyme A[blank_end] to form a [blank_start]thioester[blank_end] bond. This forms an a[blank_start]cetyl CoA[blank_end] molecule and a c[blank_start]arbon dioxide molecule[blank_end]. This forms [blank_start]NADH[blank_end] + H+ from NAD. This reaction is catalysed by [blank_start]pyruvate dehydrogenase[blank_end].
Responda
-
yruvate
-
oenzyme A
-
thioester
-
cetyl CoA
-
arbon dioxide molecule
-
NADH
-
pyruvate dehydrogenase
Questão 6
Questão
What enzyme catalyses the formation of citrate from oxaloacetate and acetyl CoA in the TCA cycle?
Responda
-
Citrate synthase
-
Acetyl CoA hydrolase
-
Oxaloacetate carboxylase
-
Enolase
Questão 7
Questão
What is the function of aconitase in the TCA cycle?
Questão 8
Questão
Isocitrate is decarboxylated to what molecule in the TCA cycle?
Responda
-
a-ketoglutarate
-
Glutamine
-
Succinyl CoA
-
Isocitrate
Questão 9
Questão
Which enzyme forms a-ketoglutarate?
Questão 10
Questão
NADH + H+ is formed from NAD+ when isocitrate is decarboxylated to a-ketoglutarate.
Questão 11
Questão
a-ketoglutarate is decarboxylated by ketoglutatate dehydrognease to what molecule?
Responda
-
Succinyl CoA
-
Succinate
-
Fumarate
-
Malate
Questão 12
Questão
NADH + H+ are formed from NAD+ when a-ketoglutarate is decarboxylated to succinyl CoA.
Questão 13
Questão
What is formed when succinyl CoA is cleaved to form succinate?
Responda
-
GTP
-
GDP and Pi
-
ATP
-
NADH + H+
Questão 14
Questão
Which enzyme catalysed the cleavage of succinyl CoA to succinate?
Questão 15
Questão
What does succinate dehydrognease do?
Responda
-
Oxidise succinate to fumarate
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Cleave succinyl CoA into succinate
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Oxidise succinate to malate
-
Oxidise succinate to oxaloacetate
Questão 16
Questão
During which reaction of the TCA cycle is FADH2 formed?
Responda
-
Oxidation of succinate to fumarate
-
Cleavage of succinyl CoA to succinate
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Hydration of fumarate to malate
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Oxidation of malate to oxaloacetate
Questão 17
Questão
When fumarate is hydrated by fumarase, what molecule is formed?
Responda
-
Malate
-
Succinate
-
Oxaloacetate
-
a-ketoglutarate
Questão 18
Questão
What enzyme oxidises malate to oxaloacetate in the final stage of the TCA cycle?
Responda
-
Malate dehydrogenase
-
Oxaloacetate synthase
-
Citrate synthase
-
Fumarase
Questão 19
Questão
NADH + H+ are formed from NAD in the oxidation of malate to oxaloacetate in the TCA cycle.
Questão 20
Questão
Fill in the blanks below to summarise each reaction of the TCA cycle based on the type of reaction it is.
1. [blank_start]Condensation[blank_end]
2. [blank_start]Isomerisation[blank_end]
3. [blank_start]Decarboyxlation[blank_end]
4. [blank_start]Decarboxylation[blank_end]
5. [blank_start]Cleavage[blank_end]
6. [blank_start]Oxidation[blank_end]
7. [blank_start]Hydration[blank_end]
8. [blank_start]Oxidation[blank_end]
Responda
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Condensation
-
Isomerisation
-
Decarboyxlation
-
Decarboxylation
-
Cleavage
-
Oxidation
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Hydration
-
Oxidation
Questão 21
Questão
Fill in the blanks below to describe the reactions of the TCA cycle.
1. First, acetyl CoA and [blank_start]oxaloacetate[blank_end] combine to form the 6-carbon compound [blank_start]citrate[blank_end]. This is catalysed by citrate synthase.
2. Then, [blank_start]citrate[blank_end] is isomerised to [blank_start]isocitrate[blank_end]. This is catalysed by [blank_start]aconitase[blank_end].
3. [blank_start]Isocitrate[blank_end] is decarboxylated to [blank_start]a-ketoglutarate[blank_end]. This is catalysed by [blank_start]isocitrate dehydrogenase[blank_end] and forms NADH and H+ from [blank_start]NAD+[blank_end].
4. [blank_start]a-ketoglutarate[blank_end] is decarboxylated to [blank_start]succinyl CoA[blank_end]. This involves addition of [blank_start]coenzyme A[blank_end] and is catalysed by [blank_start]ketoglutarate dehydrogenase[blank_end]. This also forms [blank_start]NADH[blank_end].
5. [blank_start]Succinyl CoA[blank_end] is cleaved into s[blank_start]uccinate[blank_end] and coenzyme A by [blank_start]succinate thiolase[blank_end]. This forms [blank_start]GTP[blank_end] from [blank_start]GDP[blank_end] and inorganic phosphate.
6. [blank_start]Succinate[blank_end] is decarboxylated into [blank_start]fumarate[blank_end]. This is catalysed by [blank_start]succinate dehydrogenase[blank_end] and forms [blank_start]FADH2[blank_end].
7. [blank_start]Fumarate[blank_end] is hydrated to form [blank_start]malate[blank_end]. This is catalysed by [blank_start]fumarase[blank_end].
8. [blank_start]Malate[blank_end] is decarboxylated into [blank_start]oxaloacetate[blank_end]. This is catalysed by [blank_start]malate dehydrogenase[blank_end] and forms [blank_start]NADH[blank_end].
9. The cycle repeats.
Questão 22
Questão
How many molecules of ATP are yielded from 1 molecule of NADH?
Questão 23
Questão
How many molecules of ATP are yielded from 1 molecule of FADH2?
Questão 24
Questão
How many molecules of ATP are yielded from one molecule of GTP?
Questão 25
Questão
Which minerals are the carrier protein complexes in the electron transfer chain dependent on? Select all that apply.
Responda
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Copper
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Iron
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Calcium
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Chromium
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Manganese
Questão 26
Questão
Fill in the blanks below to describe oxidative phosphorylation.
1. The proton pump on the [blank_start]inner[blank_end] mitochondrial membrane moves [blank_start]protons[blank_end] into the [blank_start]intermembranal space[blank_end]. This id driven by [blank_start]NADH[blank_end].
2. The [blank_start]pH[blank_end] of the intermembranal space [blank_start]decreases[blank_end].
3. A gradient of [blank_start]H+[blank_end] ions is produced.
4. Protons move back into the [blank_start]matrix[blank_end] via [blank_start]ATP synthase[blank_end] causing it to [blank_start]rotate[blank_end].
5. [blank_start]Rotational[blank_end] energy is used to synthesise [blank_start]ATP[blank_end] from ADP and Pi.
Responda
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inner
-
protons
-
intermembranal space
-
NADH
-
pH
-
decreases
-
H+
-
matrix
-
ATP synthase
-
rotate
-
Rotational
-
ATP
Questão 27
Questão
Fill in the blanks below to describe the yield from the TCA cycle.
Each TCA cycle yields [blank_start]3[blank_end] NADH molecules. [blank_start]3[blank_end] x [blank_start]2.5[blank_end] = [blank_start]7.5[blank_end] ATP from NADH.
Each TCA cycle yields [blank_start]1[blank_end] FADH2 molecule. [blank_start]1[blank_end] x [blank_start]1.5[blank_end] = [blank_start]1.5[blank_end] ATP from FADH2.
Each TCA cycle yields [blank_start]1[blank_end] GTP molecule. [blank_start]1[blank_end] x [blank_start]1[blank_end] = [blank_start]1[blank_end] ATP from GTP.
This totals to [blank_start]10[blank_end] ATP per TCA cycle.
Responda
-
3
-
3
-
2.5
-
7.5
-
1
-
1
-
1.5
-
1.5
-
1
-
1
-
1
-
1
-
10
Questão 28
Questão
Which enzymes are involved in irreversible steps of the TCA cycle that regulate it by feedback inhibition?
Questão 29
Questão
Fill in the blanks below to describe the feedback inhibition of the 3 irreversible enzyme steps of the TCA cycle.
Isocitrate dehydrogenase is inhibited by [blank_start]NADH[blank_end] and activated by [blank_start]ADP[blank_end].
Ketoglutarate dehydrogenase is inhibited by [blank_start]NADH[blank_end] and s[blank_start]uccinyl CoA[blank_end].
Citrate synthase is inhibited by N[blank_start]ADH[blank_end] and [blank_start]succinyl CoA[blank_end].
Responda
-
NADH
-
ADP
-
NADH
-
uccinyl CoA
-
succinyl CoA
-
ADH
Questão 30
Questão
Label this image to show the other fates of some of the intermediates in the TCA cycle.
Responda
-
Pyruvate
-
Pyruvate decarboxylase
-
Glutamate
-
Aspartate
-
Transamination
-
Phosphoenol pyruvate
-
Glucose
-
Fatty acids
-
Pyruvate
Questão 31
Questão
Fill in the blanks below to describe the links between the TCA cycle and biosynthesis.
Pyruvate can be converted to [blank_start]oxaloacetate[blank_end] by [blank_start]pyruvate carboxylase[blank_end].
[blank_start]Citrate[blank_end] can be used to form fatty acids and sterols.
[blank_start]A-ketoglutarate[blank_end] can be involved in transamination reactions to form g[blank_start]lutamate[blank_end].
[blank_start]Malate[blank_end] can form pyruvate in a reaction catalysed by [blank_start]malic enzyme[blank_end].
Oxaloacetate can be converted to [blank_start]phosphoenol pyruvate[blank_end] by [blank_start]phosphoenol pyruvate carboxylase[blank_end] and then into [blank_start]glucose[blank_end].
Oxaloacetate can be involved in [blank_start]transamination[blank_end] reactions to form a[blank_start]spartate[blank_end].