M&n Week 2: Tca Cycle

Front 1

What are the components of the pyruvate dehydrogenase complex?

Back 1

1. E1: pyruvate dehydrogenase
2. E2: dihydrolipoyl transacetylase
3. E3: dihydrolypoyl dehydrogenase

Front 2

Which enzyme converts pyruvate to Acetyl-CoA?

Back 2

Pyruvate dehydrogenase complex

Front 3

E1 requires which coenzyme?

Back 3

Thiamine pyrophopshate (TPP)
(Vitamin B1)

Front 4

E2 requires which coenzymes?

Back 4

1. Lipoic acid
2. CoA (pantothenic acid)

Front 5

E3 requires which coenzymes?

Back 5

1. FAD (riboflavin; Vitamin B2)
2. NAD+ (niacin)

Front 6

What is the affect of NADH and Acetyl-CoA on pyruvate dehydrogenase complex?

Back 6

Inhibition

Front 7

What is the indirect affect of Calcium on pyruvate dehydrogenase complex?

Back 7

Activation

Front 8

Which intermediate of the TCA cycle is also produced in the urea cycle?

Back 8

Fumarate

Front 9

Are sugars, amino acids, and fatty acids oxidizing or reducing agents?

Back 9

Reducing agents

Front 10

Are NAD+ and FAD+ oxidizing or reducing agents?

Back 10

Oxidizing agents

Front 11

Where are TCA cycle enzymes located?

Back 11

Mitochondrial matrix

Front 12

Where are fatty acid oxidation enzymes located?

Back 12

Mitochondrial matrix

Front 13

Where is pyruvate broken down within the cell?

Back 13

Mitochondrial matrix

Front 14

How are fatty acids converted to Acetyl-CoA?

Back 14

B-oxidation

Front 15

Into which space are protons pumped in the electron transport chain?

Back 15

Innermembrane space

Front 16

Which has a higher pH-- the mitochondrial matrix or the intermembrane space?

Back 16

Mitochondrial matrix

Front 17

ATP synthase passes protons from which space to which space?

Back 17

From inner mitochondrial membrane space to matrix

Front 18

Which state of respiration provides an overall indication of ATP synthase, electron transport, and Kreb's cycle function?

Back 18

State 3

Front 19

Which state of respiration provides an index for membrane integrity?

Back 19

State 4

Front 20

What could a high rate of state 4 respiration indicate?

Back 20

Membrane has been damaged, or uncoupling proteins in an effort to produce heat

Front 21

What is the respiratory control ratio?

What does a high RCR indicate?

Back 21

State 3/ State 4

High RCR indicates that electron transport and ATP synthesis are tightly coupled

Front 22

What does a low RCR indicate?

Back 22

Indicative of a high rate of proton leak-- referred to as "uncoupled."

Front 23

Which coenzyme found within the pyruvate dehydrogenase complex breaks C-C bonds?

Back 23

Thiamine pyrophosphate (TPP)
(associated with E1)

Front 24

Which coenzyme associated with E2 serves as a carrier for acetate, for delivery to the TCA cycle?

Back 24

CoA

Front 25

Which 3 enzymes in the TCA cycle are highly regulated?

Are these reactions favorable or unfavorable?

Back 25

1. Citrate synthase
2. Isocitrate dehydrogenase
3. a-Ketoglutarate dehydrogenase

*HIGHLY favorable

Front 26

Which enzyme in the TCA cycle forms a C-C bond?

Back 26

Citrate synthase

Front 27

Is aconitase thermodynamically favorable or unfavorable?

Back 27

UNFAVORABLE

Front 28

What are the 2 types (isoforms) of Isocitrate dehydrogenase?

Back 28

One uses NAD+ while the other uses NADP+

Front 29

How does a-ketogluterate dehydrogenase differ from pyruvate dehydrogenase?

Back 29

Unlike PDH, a-KGDH is not regulated by phosphorylation/dephosphorylation.
(Otherwise, the enzyme complexes are practically identical)

Front 30

Which enzyme performs substrate level phosphorylation?

Back 30

Succinyl-CoA synthetase (thiokinase)

*GTP is formed

Front 31

Which enzyme is the only one that participates in both the Krebs cycle and the ETC?

Back 31

Succinyl CoA dehydrogenase

Front 32

Which enzyme produces FADH2?

Back 32

Succinyl CoA dehydrogenase

(directly donates FADH2 to ETC)

Front 33

Which enzyme of the TCA cycle is the most thermodynamically UNFAVORABLE?

How does this reaction take proceed?

Back 33

Malate dehydrogenase

Rxn is driven by citrate synthase, which is highly favorable

Front 34

CO2 is released by which 2 reactions in the TCA cycle?

Back 34

1. Isocitrate dehydrogenase
2. a-ketogluterate dehydrogenase

Front 35

NADH is produced by which 3 reactions in the TCA cycle?

Back 35

1. Isocitrate dehydrogenase
2. a-ketogluterate dehydrogenase
3. Malate dehydrogenase

Front 36

How is isocitrate dehydrogenase allosterically inhibited?

Back 36

1. ATP
2. NADH

Front 37

How is isocitrate dehydrogenase allosterically activated?

Back 37

1. ADP
2. Ca2+

Front 38

How is a-ketogluterate dehydrogenase allosterically activated?

Back 38

Ca2+

Front 39

How is a-ketogluterate dehydrogenase allosterically inactivated?

Back 39

1. ATP
2. GTP
3. NADH
4. Succinyl CoA

Front 40

How is citrate synthase allosterically inhibited?

Back 40

1. Citrate
2. NADH
3. Succinyl CoA
4. ATP

Front 41

Succinyl CoA allosterically inhibits which enzymes of the TCA cycle?

Back 41

1. Citrate synthase
2. a-ketogluterate dehydrogenase

Front 42

How is pyruvate dehydrogenase complex allosterically inhibited?

Back 42

1. ATP
2. NADH
3. Acetyl-CoA
4. Fatty acids

Front 43

How is pyruvate dehydrogenase complex allosterically activate?

Back 43

1. AMP
2. CoA
3. NAD+
4. Ca2+

Front 44

List 3 examples of anaplerotic reactions.

Back 44

1. Pyruvate carboxylase (pyruvate --> oxaloacetate)
2. PEP carboxykinase (PEP --> oxaloacetate)
3. Malic enzyme (pyruvate --> malate)

Front 45

List 2 shuttle systems utilized for transporting electrons from NADH produced in the cytosol across the inner mitochondrial membrane for utilization by the ETC.

Back 45

1. Glycerol 3-phosphate shuttle
2. Malate-Aspartate shuttle