Unit I Krebs Cycle

Question 1

Whats another name for Krebs cycle?

Answer 1

citric acid cycle, or tricarboxylic acid cycle

Question 2

What system has the greatest production of ATP?

Answer 2

Krebs cycle (aerobic respiration)

Question 3

Where does krebs take place?

Answer 3

mitochondrial matrix

Question 4

What 3 things does krebs break down?

Answer 4

fats, carbs,and proteins

Question 5

What other pathway runs with krebs?

Answer 5

electron transport system

Question 6

Where does ETS take place?

Answer 6

inner mitochondrial matrix

Question 7

What are krebs’ main products?

Answer 7

NADH, FADH2, GTP, and CO2

Question 8

What are ETS’ main products?

Answer 8

ATP, CO2, and H20

Question 9

What the main reactants of Krebs?

Answer 9

fats, carbs, proteins, Acetyl CoA

Question 10

What are the main reactants of ETS?

Answer 10

ADP, Pi, NADH, FADH2, and Oxygen

Question 11

What key enzymes are used in aerobic respiration?

Answer 11

dehydrogenases

Question 12

How does a carb enter the kreb cycle?

Answer 12

As acetyl CoA after running through glycolysis and a prep step

Question 13

How does a fat enter Krebs?

Answer 13

As acetyl CoA after being beta oxidized

Question 14

How does a protein enter the krebs cycle?

Answer 14

Each AA has a unique way to enter, but mostly acetyl CoA

Question 15

Shortly describe how glucose would enter krebs?

Answer 15

Glucose would become pyruvate then converted to Acetyl CoA after a prep step. Acetyl CoA can then enter the cycle

Question 16

How does Acyl CoA enter the krebs cycle?

Answer 16

Its converted to Acetyl CoA after Beta Oxidation

Question 17

What is the important carrier of both Acyl and Acetyl CoA?

Answer 17

Coenzyme A

Question 18

How would a fatty acid enter krebs again?

Answer 18

through beta oxidation

Question 19

Where in the cell would Beta Oxidation take place?

Answer 19

in the mitochondrial matrix

Question 20

How would amino acids enter krebs usually?

Answer 20

as Acetyl CoA

Question 21

Besides Acetyl CoA, how else can amino acids enter krebs?

Answer 21

oxaloacetate, alpha ketoglutarate, succinyl CoA, and fumarate

Question 22

Pyruvate is converted in to acetyl CoA by what enzyme?

Answer 22

pyruvate dehydrogenase complex

Question 23

Where does the pyruvate conversion to acetyl CoA take place?

Answer 23

inside the mitochondrial matrix

Question 24

What couples with pyruvate dehydrogenase?

Answer 24

NAD is reduced to NADH and a CO2 is given off

Question 25

How many enzymes are in the pyruvate dehydrogenase complex?

Answer 25

3

Question 26

How many co-enzymes are in the pyruvate dehydrogenase complex?

Answer 26

5

Question 27

List the co-enzymes of the pyruvate dehydrogenase complex?

Answer 27

thiamine pyrophosphate, FAD, NAD, coenzyme A,and lipoate

Question 28

In the first step of Krebs, acetyl CoA and oxaloacetate are catalyzed by what enzyme to create citric acid (citrate)?

Answer 28

citrate synthase

Question 29

What is citrate synthase coupled with to create citrate?

Answer 29

H20 and Coenzyme A

Question 30

Aconitase converts citric acid to what?

Answer 30

isocitric acid (isocitrate)

Question 31

What is the unstable intermediate of isocitrate to alpha ketoglutarate?

Answer 31

oxalosuccinate

Question 32

what converts isocitrate to oxalosuccinate?

Answer 32

isocitrate dehydrogenase

Question 33

What coverts oxalosuccinate to alpha ketoglutarate?

Answer 33

isocitrate dehydrogenase

Question 34

Isocitrate to alpha ketoglutarate is said to be oxidative carboxylation because

Answer 34

NAD gains an electron and CO2 is given off

Question 35

What enzyme converts alpha ketoglutarate to succinyl CoA?

Answer 35

the alpha ketoglutarate dehydrogenase complex

Question 36

The reaction of alpha ketoglutarate to succinyl CoA is said to be oxidative decarboxylation because

Answer 36

NAD gains an electron and CO2 is given off

Question 37

what co-enzyme is coupled with alpha ketoglutarate dehydrogenase complex?

Answer 37

Coenzyme A

Question 38

How many enzymes are in the alpha ketoglutarate complex and what type of enzymes?

Answer 38

3; dehydrogenase transferase dehydrogenase

Question 39

how many coenzymes are in the alpha ketoglutarate complex?

Answer 39

TPP, FAD, NAD, Coenzyme A, and lipoate

Question 40

What steps have given off CO2 so far?

Answer 40

pyruvate dehydrogenase complex, isocitrate dehydrogenase, and alpha ketoglutarate dehydrogenase complex

Question 41

Succinate thiokinase converts what to succinate?

Answer 41

succinyl CoA

Question 42

What is another name for succinate thiokinase?

Answer 42

Succinyl CoA synthetase

Question 43

What are the other products besides succinate that succinate thiokinase makes?

Answer 43

GTP and Coenzyme A

Question 44

What is the one reaction in the TCA that yields a high energy phosphate bond?

Answer 44

succinyl CoA to succinate

Question 45

How does GTP become ATP?

Answer 45

react GTP with ADP and nucleoside diphosphokinase

Question 46

Is the conversion of GTP to ATP reversible?

Answer 46

it is reversible

Question 47

When succinate dehydrogenase reacts with succinate what is made?

Answer 47

fumarate

Question 48

What is coupled with succinate dehydrogenase?

Answer 48

FAD

Question 49

What is succinate dehydrogenase bound to?

Answer 49

the inner mitochondrial membrane

Question 50

For fumarate to become malate what must happen?

Answer 50

Fumarate gets hydrated by fumarase

Question 51

what is coupled with fumarase?

Answer 51

H20

Question 52

What converts malate to oxaloacetate?

Answer 52

malate dehydrogenase

Question 53

What is coupled with malate dehydrogenase?

Answer 53

NAD

Question 54

List some conditions that would inhibit pyruvate dehydrogenase

Answer 54

High NADH, acetyl CoA, ATP, and LCFA's

Question 55

How is pyruvate dehydrogenase inhibited by high energy conditions?

Answer 55

a kinase is activated by these conditions and adds a phosphate to pyruvate dehydrogenase making it inactive

Question 56

What are the key regulatory steps of krebs?

Answer 56

pyruvate dehydrogenase complex, citrate synthase, isocitrate dehydrogenase, and alpha ketoglutarate dehydrogenase complex

Question 57

Which products in high concentration would inhibit citrate synthase?

Answer 57

ATP and citrate

Question 58

Which reactants in low concentration would inhibit citrate synthase?

Answer 58

oxaloacetate or acetyl CoA

Question 59

What products in high concentration would inhibit isocitrate dehydrogenase?

Answer 59

ATP and NADH

Question 60

What reactants in high concentration would stimulate isocitrate dehydrogenase?

Answer 60

ADP and NAD

Question 61

What would be examples of products inhibiting the alpha-ketoglutarate dehydrogenase complex?

Answer 61

ATP, NADH, and Succinyl CoA

Question 62

Define anaplerotic

Answer 62

giving substrates to a cycle

Question 63

Define Cataplerotic

Answer 63

taking substrates from the cycle

Question 64

What are the final common products of aerobic metabolism?

Answer 64

CO2 and H20

Question 65

What is the purpose of krebs cycle again?

Answer 65

ATP