E1 Krebs Cycle

Question 1

What type of respiration will have the greatest production of ATP?

Answer 1

Aerobic

Question 2

Define oxidative phosphorylation.

Answer 2

Production of ATP using energy created by electron flow down the electron transport system to the final electron acceptor

Question 3

What is the final electron acceptor?

Answer 3

Oxygen

Question 4

Consume macronutrients –> ___________ –> produce _________ –> oxygen _______ the electrons –> use energy created by flow of electrons to male ATP

Answer 4

Oxidize macronutrients; reduced compounds, accepts

Question 5

Where does Kreb’s Cycle occur? Electron Transport System?

Answer 5

Mitochondrial Matrix: Inner Membrane

Question 6

What are the three names for the cycle that produces citric acid?

Answer 6

Krebs cycle, Citric acid cycle, Tricarboxylic acid cycle

Question 7

True or False- Krebs is the first step in oxidation of macronutrients.

Answer 7

False- final step

Question 8

What are the overall products of Krebs?

Answer 8

CO2, GTP, NADH, FADH2

Question 9

Where do the reduced compounds (NADH, FADH2) take their electrons to make ATP?

Answer 9

ETS

Question 10

List in order the main reactants of Krebs.

Answer 10

Acetyl CoA, citrate, isocitrate, alpha ketoglutarate, succinyl CoA, succinate, fumarate, malate, oxaloacetate

Question 11

Coenzyme A consists of what two things?

Answer 11

Pantothenic Acid (VB5) and a terminal thiol group (thioester bond)

Question 12

What is the conversion process of glucose to pyruvate called? Where does it occur?

Answer 12

Glycolysis; Cytosol

Question 13

Pyruvate is produced in the Cytosol via glycolysis. Where does pyruvate become acetyl CoA? What is this step called?

Answer 13

Mitochondrial Matrix; Prep Step

Question 14

What are the reactants of pyruvate dehydrogenase complex?

Answer 14

Pyruvate, NAD+, CoA

Question 15

What are the products of pyruvate dehydrogenase complex?

Answer 15

Acetyl CoA, NADH, CO2,

Question 16

The conversion of pyruvate to acetyl CoA will use what enzyme? What type of reaction? Reversible?

Answer 16

Pyruvate dehydrogenase complex, decarboxylation, irreversible

Question 17

How many carbons does pyruvate have?

Answer 17

3

Question 18

How many carbons does acetyl CoA have?

Answer 18

2

Question 19

How many enzymes and coenzymes does pyruvate dehydrogenase complex have?

Answer 19

3 enzymes, 5 coenzymes

Question 20

In the reaction of pyruvate to acetylene CoA, is pyruvate oxidized to reduced?

Answer 20

Oxidized

Question 21

List the 5 coenzymes of pyruvate dehydrogenase complex.

Answer 21

Thiamine Phosphate (TPP)- thiamine
FAD- riboflavin
Lipoate- lipoid acid
NAD- niacin (R)
Coenzyme A- pantothenic acid (R)

Question 22

Since the prep step is irreversible, what can the acetyl CoA do?

Answer 22

Enter Krebs or lipid synthesis

Question 23

What will inhibit PDH?

Answer 23

Increased products- acetyl CoA, NADH, high energy levels

Question 24

Will phosphorylation of PDH by PDH kinase inhibit or stimulate PDH?

Answer 24

Inhibit

Question 25

True or False- PDH phosphatase will stimulate PDH

Answer 25

True

Question 26

What will stimulate PDH?

Answer 26

Low energy, low acetyl CoA, calcium, epinephrine, insulin

Question 27

What will happen if you are deficient in PDH?

Answer 27

Cannot produce acetyl CoA Increase lactic acid Ketogenic diet

Question 28

Increased PDH kinase activity will increase ___________.

Answer 28

Cancer risk

Question 29

What disease will occur if you are Thiamine deficient?

Answer 29

BeriBeri (dietary) (high pyruvate levels in blood)

Question 30

Where does beta oxidation occur?

Answer 30

Matrix

Question 31

Beta oxidation allows for the entry of what?

Answer 31

Fatty acid

Question 32

An 18C long chain FA will produce how many acetyl CoA to enter Krebs?

Answer 32

9

Question 33

Is beta oxidation an energy producing pathway?

Answer 33

Yes

Question 34

List the amino acid entry intermediates.

Answer 34

Pyruate, Acetyl CoA, alpha ketoglutarate, succinyl CoA, fumarate, oxaloacetate

Question 35

List the reactants of citrate synthase.

Answer 35

Acetyl CoA, oxaloacetate, water

Question 36

List the products of citrate synthase.

Answer 36

Citrate, CoA,

Question 37

What enzyme is used to create citrate?

Answer 37

Citrate synthase

Question 38

Acetyl CoA + OOA --> Citrate is what type of reaction?

Answer 38

Condensation/Dehydration

Question 39

How many carbons does citrate have?

Answer 39

6

Question 40

List the reactants of aconitase.

Answer 40

Citrate

Question 41

List the products of aconitase.

Answer 41

Isocitrate

Question 42

What enzyme is used to convert citrate into isocitrate?

Answer 42

Aconitase

Question 43

Citrate --> Isocitrate is what type of reaction?

Answer 43

Isomerization

Question 44

List the reactants of isocitrate dehydrogenase.

Answer 44

Isocitrate, NAD+

Question 45

List the products of isocitrate dehydrogenase.

Answer 45

Alpha ketoglutarate, NADH, CO2

Question 46

What enzyme is used to convert isocitrate to alpha ketoglutarate?

Answer 46

Isocitrate dehydrogenase

Question 47

Isocitrate --> alpha ketoglutarate is what type of reaction?

Answer 47

Oxidative decarboxylation

Question 48

How many carbons does alpha ketoglutarate have?

Answer 48

5

Question 49

Why is isocitrate dehydrogenase an important regulatory step in Krebs? What will stimulate it? Inhibit?

Answer 49

Sensitive to change in the cell Stimulate- low energy (ADP) Inhibit- high energy (ATP), NADH

Question 50

List the reactants of alpha ketoglutarate dehydrogenase complex.

Answer 50

Alpha ketoglutarate, NAD+, CoA

Question 51

List the products of alpha ketoglutarate dehydrogenase complex.

Answer 51

Succinyl CoA, NADH, CO2

Question 52

What enzyme is used to convert alpha ketoglutarate into succinyl CoA?

Answer 52

Alpha ketoglutarate dehydrogenase complex

Question 53

Alpha ketoglutarate --> succinyl CoA is what type of reaction?

Answer 53

Oxidative decarboxylation

Question 54

How many carbons does succinyl CoA have?

Answer 54

4

Question 55

What is the rate limiting step of Krebs? What stimulates it? Inhibit?

Answer 55

Alpha ketoglutarate dehydrogenase complex Stimulate- NADH, succinyl CoA Inhibit- high energy (ATP)

Question 56

List the reactants of succinate thiokinase.

Answer 56

Succinyl CoA, GDP, Pi

Question 57

List the products of succinate thiokinase.

Answer 57

Succinate, CoA, GTP

Question 58

What enzyme is used to convert succinyl CoA to succinate?

Answer 58

Succinate thiokinase

Question 59

How many carbons does succinate have?

Answer 59

4

Question 60

List the reactants of succinate dehydrogenase.

Answer 60

Succinate, FAD

Question 61

List the products of succinate dehydrogenase.

Answer 61

Fumarate, FADH2

Question 62

What enzyme is used to convert succinate to fumarate?

Answer 62

Succinate dehydrogenase

Question 63

Succinate --> Fumarate is what type of reaction?

Answer 63

Oxidation

Question 64

What is the location of succinate dehydrogenase?

Answer 64

Partially bound to the inner mitochondrial membrane | Aka complex 2 of ETS

Question 65

How many carbons does fumarate have?

Answer 65

4

Question 66

List the reactants of fumarase.

Answer 66

Fumarate, water

Question 67

List the products of fumarase.

Answer 67

Malate

Question 68

What enzyme is used to convert fumarate to malate?

Answer 68

Fumarase

Question 69

Fumarate --> Malate is what type of reaction?

Answer 69

Condensation/dehydration

Question 70

How many carbons does malate have?

Answer 70

4

Question 71

List the reactants of malate dehydrogenase.

Answer 71

Malate, NAD+

Question 72

List the products of malate dehydrogenase.

Answer 72

Oxaloacetate, NADH

Question 73

What enzyme is used to convert malate to oxaloacetate?

Answer 73

Malate dehydrogenase

Question 74

Malate --> Oxaloacetate is what type of reaction?

Answer 74

Oxidation

Question 75

How many carbons does oxaloacetate have?

Answer 75

4

Question 76

Match the product to the appropriate enzyme.

Answer 76

``` Citrate- citrate synthase Isocitrate- aconitase Alpha ketoglutarate- isocitrate dehydrogenase Succinyl CoA- alpha ketoglutarate dehydrogenase complex Succinate- succinate thiokinase Fumarate- succinate dehydrogenase Malate- fumarase Oxaloacetate- malate dehydrogenase ```

Question 77

How many turns of the Krebs cycle? Each turn will yield how many NADH? FADH2? GTP?

Answer 77

2 turns; 3 NADH; 1 FADH2; 1 GTP

Question 78

How many total ATP will Krebs yield?

Answer 78

10

Question 79

Krebs is the "hub" for intermediates. Succinyl CoA will make ____. Citrate will make _____. OOA and. Alpha ketoglutarate will make ______.

Answer 79

Heme; FAs and sterols; amino acids

Question 80

What is the term for giving substrates to the cycle?

Answer 80

Anaplerotic

Question 81

What is the term for taking substrates from the cycle?

Answer 81

Cataplerotic

Question 82

List the dehydrogenase enzymes.

Answer 82

Isocitrate DH, alpha ketoglutarate DH, succinate DH, malate DH

Question 83

What are the two regulatory enzymes?

Answer 83

Isocitrate DH and alpha ketoglutarate DH

Question 84

The products stimulate or inhibit? List the products of Krebs.

Answer 84

Inhibit; ATP, NADH, FADH2

Question 85

The reactants will stimulate or inhibit? List the reactants.

Answer 85

Stimulate; ADP, NAD+, FAD, acetyl CoA