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Biochem 2- PCCF tri 2 > exam 2 (glycolysis, krebs, etc) > Flashcards

exam 2 (glycolysis, krebs, etc) Flashcards

1
Q

What is the primary function of the Electron Transport Chain?

A

To generate ATP by transferring electrons and creating a proton gradient

The process involves NADH and FADH2 transferring electrons through various complexes.

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2
Q

What is the ultimate electron acceptor in the Electron Transport Chain?

A

Oxygen

Oxygen combines with electrons and protons to form water.

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3
Q

What is produced when oxygen joins with electrons in the Electron Transport Chain?

A

Water

This reaction is crucial for maintaining the flow of electrons.

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4
Q

What are the main complexes involved in the Electron Transport Chain?

A

I, II, III, IV

These complexes are responsible for transferring electrons and pumping protons.

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5
Q

Which complex is responsible for transferring electrons from NADH?

A

Complex I

Complex I also contributes to the proton gradient.

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6
Q

What is the role of succinate dehydrogenase in the Electron Transport Chain?

A

It transfers electrons from FADH2 to CoQ

Succinate dehydrogenase is part of Complex II.

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7
Q

What is CoQ commonly known as?

A

Ubiquinone

Ubiquinone plays a key role in electron transport.

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8
Q

Which complexes build the proton gradient in the Electron Transport Chain?

A

I, III, IV

These complexes pump protons from the mitochondrial matrix into the intermembrane space.

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9
Q

What does Complex II do in the Electron Transport Chain?

A

Transfers electrons from FADH2 to CoQ

Complex II does not contribute to the proton gradient.

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10
Q

True or False: The Electron Transport Chain operates sequentially.

A

False

The complexes operate in parallel, allowing flexibility in electron transfer.

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11
Q

What is the significance of the proton gradient created by the Electron Transport Chain?

A

It drives the synthesis of ATP

The gradient is utilized by ATP synthase to produce ATP from ADP and inorganic phosphate.

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12
Q

Fill in the blank: The process of ATP synthesis in the Electron Transport Chain is powered by the _______.

A

proton gradient

This gradient is established by the activity of the electron transport complexes.

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13
Q

What is the main role of cytochromes in the Electron Transport Chain?

A

To facilitate electron transfer

Cytochromes contain iron and copper, which are essential for their function.

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14
Q

What happens when electrons pass through the complexes in the Electron Transport Chain?

A

They release energy used to pump protons

This energy is crucial for creating the proton gradient.

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15
Q

What is the primary function of glucose in cellular respiration?

A

To produce pyruvate and generate energy carriers like NADH and FADH2

Glucose undergoes glycolysis to be converted into pyruvate.

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16
Q

What cannot cross the mitochondrial membrane?

A

NADH

NADH produced in the cytoplasm needs a shuttle to enter the mitochondria.

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17
Q

What shuttle is used to transport NADH into mitochondria?

A

Glycerol-3-phosphate shuttle

This shuttle operates primarily in skeletal muscle and the brain.

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18
Q

What is the outcome of using the glycerol-3-phosphate shuttle?

A

Produces FADH2 instead of NADH

This results in less ATP yield compared to NADH.

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19
Q

What process produces NADH in the cytoplasm?

A

Glycolysis

Glycolysis converts glucose into pyruvate, generating NADH in the process.

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20
Q

What is the role of the malate-aspartate shuttle?

A

To transfer NADH into mitochondria in heart and kidney cells

This shuttle allows NADH to be converted back to NAD+ in the mitochondrial matrix.

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21
Q

What is transamination?

A

The process of transferring an amino group to form aspartate from oxaloacetate

This step is crucial for the malate-aspartate shuttle to function.

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22
Q

Which complex does NADH enter in the electron transport chain?

A

Complex I

NADH contributes electrons to the electron transport chain at this complex.

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23
Q

Fill in the blank: In glycolysis, glucose is converted to _______.

A

pyruvate

This conversion is the first step in cellular respiration.

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24
Q

True or False: Aspartate can cross the mitochondrial membrane to enter the electron transport chain.

A

True

Aspartate can be converted back to oxaloacetate in the mitochondria.

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25
What does FADH2 yield compared to NADH when entering the electron transport chain?
Less ATP ## Footnote FADH2 contributes fewer protons to the gradient than NADH.
26
What is the primary function of the pyruvate dehydrogenase complex?
To convert pyruvate into Acetyl-CoA
27
Which of the following is NOT a product of the pyruvate dehydrogenase complex?
CoA
28
List the products of the pyruvate dehydrogenase complex.
* NADH FADH * Acetyl-CoA * CO2
29
What inhibits the pyruvate dehydrogenase complex allosterically?
High ATP levels
30
What activates the pyruvate dehydrogenase complex allosterically?
AMP
31
Fill in the blank: The Krebs cycle is also known as the _______.
citric acid cycle
32
What are the starting materials for the Krebs cycle?
* Acetyl-CoA * Oxaloacetate
33
What is produced during the Krebs cycle?
* NADH * FADH2 * GTP * H2O
34
True or False: Water is a reactant in the Krebs cycle.
True
35
What is the role of lipoic acid in the pyruvate dehydrogenase complex?
It acts as a coenzyme
36
Name one coenzyme involved in the pyruvate dehydrogenase complex.
Thiamine pyrophosphate (TPP)
37
What is the final product of the Krebs cycle that is regenerated?
Oxaloacetate
38
What vitamin is needed for the pyruvate dehydrogenase complex?
Thiamine ## Footnote Thiamine is essential for the decarboxylation of pyruvate.
39
What is the function of the pyruvate dehydrogenase complex?
To decarboxylate pyruvate and add CoA ## Footnote This process converts pyruvate into acetyl-CoA.
40
What are the products of pyruvate decarboxylation?
* Acetyl-CoA * CO2 * NADH ## Footnote This reaction is catalyzed by the pyruvate dehydrogenase complex.
41
What is the primary substrate entering the Krebs cycle?
Acetyl-CoA ## Footnote Acetyl-CoA is derived from pyruvate and fatty acids.
42
What is the first molecule formed in the Krebs cycle?
Citrate ## Footnote Citrate is formed when Acetyl-CoA combines with oxaloacetate.
43
How many NADH are produced in one round of the Krebs cycle?
3 NADH ## Footnote Each NADH can yield approximately 2.5 ATP in the electron transport chain.
44
What enzyme connects the Krebs cycle to the electron transport chain?
Succinate dehydrogenase ## Footnote This enzyme catalyzes the conversion of succinate to fumarate.
45
What are the total ATP equivalents produced from one glucose molecule through the Krebs cycle?
12 ATP equivalents ## Footnote This includes ATP from GTP and NADH/FADH2.
46
What is the main regulatory enzyme of the Krebs cycle?
Isocitrate dehydrogenase ## Footnote This enzyme regulates the flow through the cycle based on cellular energy needs.
47
Fill in the blank: The conversion of isocitrate to alpha-ketoglutarate produces ______.
NADH ## Footnote This step is crucial for energy production in the Krebs cycle.
48
True or False: Acetyl-CoA is a 3-carbon molecule.
False ## Footnote Acetyl-CoA is a 2-carbon molecule.
49
List the total energy products from one round of the Krebs cycle.
* 3 NADH * 1 FADH2 * 1 GTP ## Footnote These products are used for energy production in the electron transport chain.
50
What is the role of GTP in the Krebs cycle?
Energy creation ## Footnote GTP can be converted to ATP, contributing to the cell's energy currency.
51
What is the starting molecule for the Krebs Cycle?
Glucose ## Footnote Glucose is broken down into pyruvate during glycolysis.
52
How many NADH molecules are produced during glycolysis?
2 NADH ## Footnote NADH is a key electron carrier in cellular respiration.
53
What is the total ATP yield from glycolysis?
2 ATP ## Footnote Glycolysis occurs in the cytoplasm and does not require oxygen.
54
How many ATP equivalents are generated from 1 molecule of glucose during the complete oxidation process?
38 ATP ## Footnote This total includes ATP from glycolysis, Krebs Cycle, and the electron transport chain (ETC).
55
What is the total number of ATP equivalents produced from the Krebs Cycle?
24 ATP equivalents ## Footnote The Krebs Cycle also generates NADH and FADH2, which contribute to the ETC.
56
How many ATP are generated from one molecule of NADH in the electron transport chain?
3 ATP ## Footnote NADH contributes to the proton gradient used for ATP synthesis.
57
How many ATP are produced from one molecule of FADH2 in the electron transport chain?
2 ATP ## Footnote FADH2 is less efficient than NADH in producing ATP.
58
Fill in the blank: The Krebs Cycle is also known as the _______.
Citric Acid Cycle ## Footnote The Krebs Cycle is named after Hans Krebs, who first described it.
59
True or False: The electron transport chain is responsible for the majority of ATP production.
True ## Footnote The ETC is where the majority of ATP is produced through oxidative phosphorylation.
60
What is the total yield of ATP from the complete oxidation of one molecule of glucose when heat is not accounted for?
34 ATP ## Footnote This yield can vary slightly based on the efficiency of the processes involved.
61
What is produced when ADP and P combine?
ATP ## Footnote ATP is the primary energy carrier in cells.
62
Where does the Krebs Cycle occur?
Mitochondria ## Footnote Specifically, it takes place in the mitochondrial matrix.
63
What is the role of the electron transport chain (ETC) in the mitochondria?
Creates a proton (H+) gradient ## Footnote The ETC uses the energy from electrons to pump protons into the intermembrane space.
64
What happens to electrons as they move down the electron transport chain?
They lose energy ## Footnote This energy is used to create a proton gradient.
65
What is the importance of the H+ gradient created by the ETC?
It is crucial for ATP synthesis ## Footnote The gradient drives ATP synthase to produce ATP.
66
Name the two primary electron carriers involved in the Krebs Cycle.
NADH and FADH2 ## Footnote These carriers transport electrons to the ETC.
67
Which mitochondrial membrane separates the intermembrane space from the mitochondrial matrix?
Inner mitochondrial membrane ## Footnote The inner membrane is where the ETC and ATP synthesis occur.
68
True or False: The outer mitochondrial membrane is permeable to ions and small molecules.
True ## Footnote It allows the passage of molecules, unlike the inner membrane.
69
Fill in the blank: The _______ is the space between the outer and inner mitochondrial membranes.
intermembrane space ## Footnote This space plays a role in the proton gradient necessary for ATP production.
70
What is the first step of the Krebs Cycle?
Acetyl CoA combines with oxaloacetate to form citrate ## Footnote This step is facilitated by citrate synthase.
71
What are the key regulatory enzymes in the Krebs Cycle?
Malate dehydrogenase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase ## Footnote These enzymes regulate the flow through the cycle based on energy needs.
72
What are the products of the conversion of isocitrate to alpha-ketoglutarate?
NADH, CO2 ## Footnote This step is catalyzed by isocitrate dehydrogenase.
73
Which B vitamins are needed for the Krebs Cycle?
Niacin, Riboflavin ## Footnote These vitamins are precursors for NAD+ and FAD respectively.
74
What is the role of FADH2 in the Krebs Cycle?
It acts as an electron carrier ## Footnote FADH2 is produced during the conversion of succinate to fumarate.
75
Fill in the blank: The conversion of succinate to fumarate produces _______.
FADH2
76
What is the significance of the 'committing step' in the Krebs Cycle?
It is an irreversible reaction that determines the flow of metabolites ## Footnote This step is the conversion of citrate to isocitrate.
77
What inhibits the regulatory enzymes in the Krebs Cycle?
Energy levels, specifically NADH and FADH2 ## Footnote High levels of NADH and FADH2 indicate sufficient energy supply.
78
What are the products formed from the conversion of alpha-ketoglutarate to succinyl CoA?
NADH, CO2 ## Footnote This reaction is catalyzed by alpha-ketoglutarate dehydrogenase.
79
What is produced when succinyl CoA is converted to succinate?
GTP or ATP ## Footnote This step involves substrate-level phosphorylation.
80
Which enzyme links the Krebs Cycle to the inner mitochondrial membrane?
Succinate dehydrogenase ## Footnote This enzyme is involved in both the Krebs Cycle and the electron transport chain.
81
True or False: The Krebs Cycle occurs in the cytoplasm of the cell.
False ## Footnote The Krebs Cycle occurs in the mitochondrial matrix.
82
What is glycolysis?
A 10-step pathway that converts glucose into pyruvate, producing ATP and NADH.
83
What are the two phases of glycolysis?
* Preparatory phase * Payoff phase
84
What is the net ATP yield from glycolysis?
2 ATP
85
What is the first step of glycolysis?
Hexokinase catalyzes the conversion of glucose to glucose-6-phosphate.
86
What is the role of hexokinase in glycolysis?
Catalyzes the phosphorylation of glucose to glucose-6-phosphate using ATP.
87
What is the committing step of glycolysis?
The conversion of fructose-6-phosphate to fructose-1,6-bisphosphate.
88
What does step 4 of glycolysis involve?
Aldolase converts fructose-1,6-bisphosphate to dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP).
89
What is the function of triose phosphate isomerase?
Converts DHAP to GAP, making it usable in glycolysis.
90
What is produced in step 6 of glycolysis?
1,3-bisphosphoglycerate and NADH.
91
What is the role of phosphoglycerate kinase?
Catalyzes the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate, producing ATP.
92
What happens in step 9 of glycolysis?
Enolase catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate, involving dehydration.
93
What is the final step of glycolysis?
Phosphoenolpyruvate + ADP → pyruvate + ATP.
94
True or False: Glycolysis occurs in the mitochondria.
False
95
Fill in the blank: Glycolysis is an _______ process.
anaerobic
96
What is the purpose of NAD+ in glycolysis?
To be reduced to NADH during the oxidation of glyceraldehyde-3-phosphate.
97
Which enzyme catalyzes the conversion of glucose-6-phosphate in the regulatory step?
Phosphofructokinase-1
98
What are the end products of glycolysis?
* 2 ATP * 2 NADH * 2 Pyruvate
99
What is the significance of the conversion of phosphoenolpyruvate to pyruvate?
It is an irreversible step that generates ATP.
100
What is produced in step 7 of glycolysis?
Glycerate-3-phosphate
101
What is the role of glyceraldehyde-3-phosphate dehydrogenase?
Catalyzes the conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate.
102
What is glycolysis?
A metabolic pathway that converts glucose into pyruvate, producing ATP in the process ## Footnote Glycolysis occurs in the cytoplasm and is the first step in cellular respiration.
103
Where does glycolysis take place?
In the cytoplasm ## Footnote This is the location within the cell where glycolysis occurs.
104
What are the regulatory enzymes of glycolysis?
* Hexokinase * Phosphofructokinase (PFK) * Pyruvate kinase ## Footnote These enzymes play crucial roles in controlling the glycolytic pathway.
105
Which enzyme catalyzes the conversion of glucose to glucose-6-phosphate?
Hexokinase ## Footnote This is the first step in glycolysis.
106
What is the function of phosphofructokinase (PFK)?
Catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate ## Footnote PFK is a key regulatory step in the glycolytic pathway.
107
What reaction does pyruvate kinase catalyze?
The conversion of phosphoenolpyruvate to pyruvate ## Footnote This step produces ATP as a byproduct.
108
Is phosphoglycerate kinase a regulatory enzyme in glycolysis?
No ## Footnote It catalyzes a reaction that forms ATP but is not considered a regulatory enzyme.
109
What is the nature of the regulatory enzymes in glycolysis?
Unidirectional and irreversible ## Footnote This means they can only catalyze reactions in one direction.
110
What is the net yield of ATP from glycolysis?
2 ATP ## Footnote This is the total ATP produced after accounting for consumption during the glycolytic process.
111
Fill in the blank: Glycolysis is part of the _______.
Krebs cycle ## Footnote Glycolysis feeds into the Krebs cycle as it produces pyruvate for further energy extraction.
112
What are the products formed from glyceraldehyde-3-phosphate during glycolysis?
* Glycerate-1,3-bisphosphate * ATP ## Footnote These products are crucial for the continuation of glycolysis.
113
True or False: Glycolysis produces more ATP than it consumes.
False ## Footnote Glycolysis consumes 2 ATP and produces 4 ATP, resulting in a net gain of 2 ATP.
114
What is the Cori Cycle also known as?
Anaerobic glycolysis ## Footnote The Cori Cycle is a metabolic pathway that regenerates glucose from lactate.
115
What enzyme converts pyruvate to lactate in muscles?
Lactate dehydrogenase ## Footnote This enzyme plays a crucial role in the conversion of pyruvate during anaerobic conditions.
116
In muscles, glycolysis converts glucose to _______.
Pyruvate ## Footnote Glycolysis is the metabolic pathway that breaks down glucose for energy.
117
What is produced from pyruvate in muscles during anaerobic glycolysis?
Lactate ## Footnote Lactate is produced when oxygen is scarce and energy is needed quickly.
118
In the liver, lactate is converted back to _______.
Pyruvate ## Footnote This process helps to recycle lactate back into glucose through gluconeogenesis.
119
What happens to lactate in the bloodstream?
It is transported to the liver ## Footnote Lactate travels through the bloodstream to be converted back to pyruvate.

Biochem 2- PCCF tri 2 (3 decks)

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