Tricarboxylic Acid Cycle & Pyruvate Dehydrogenase (TCA Cycle) Chip 9

Question 1

What does TCA Cycle stand for

Answer 1

Tricarboxylic Acid Cycle-also called the Citric Acid Cycle

Question 2

What is TCA Cycle

Answer 2

Plays several roles in the metabolism
It is the final pathway where the oxidative catabolism of Carbohydrates
Amino Acids
Fatty Acids converge.

Question 3

What happens to Carb/AA/Fatty acids as they converge

Answer 3

Their carbon skeletons is being converted to CO2

Question 4

T/F Oxidation in the TCA Cycle provides energy for the production of the majority of ATP in most animals

Answer 4

True

Question 5

Where does the TCA Cycle take place

Answer 5

Mitochondria

Question 6

Electron transport reactions taking place in Mitochondria

Answer 6

Oxidize the reduced coenzymes (NADH & FADH2) produced by the cycle

Question 7

TCA is considered Aerobic or Anaerobic pathway & why

Answer 7

Aerobic Pathway

BC= O2 is required as the final electron acceptor

Question 8

What are the 8 intermediates involved in the TCA cycle

Answer 8

1. Oxalacetate
2. Citrate
3. Isocitrate
4. Alpha-Ketoglutamate
5. Succinyl-CoA
6. Succinate
7. Fumarate
8. Malate

Question 9

What are the 8 Enzymes involved in the TCA cycle

Answer 9

1. Citrate synthase
2. Aconitase
3. Isocitrate Dehydrogenase (IDM)
4. Alpha Ketaglutarate Dehydrogenase
5. Succinate Thiokinase
6. Succinate Dehydrogenase
7. Fumarase
8. Malate Dehydrogenase (DMH)

Question 10

Intermediates Mneumonics

Answer 10

Our City Is Kept Safe & Secure From Mobsters

Question 11

Which pathway leads to Pyruvate formation ?

Answer 11

Glycolysis of Glucose a 6 Carbon compound splitting in to 2 molecules of Pyruvate

Question 12

How many carbon compounds are there in Pyruvate

Answer 12

3 Carbon Compounds

Question 13

In Step 1:

Pyruvate is converted to what intermediate

Answer 13

Acetyl-CoA

Question 14

In step 1:
What is the process of Pyruvate and First intermediate formation?
Name the 1th intermediate being formed

Answer 14

Acetyl-CoA

Oxidation of Pyruvate into Acetyl-CoA

Question 15

What Enzyme is responsible for Oxidation of Pyruvate into Acetyl CoA?

Answer 15

Enzyme Pyruvate Dehydrogenase Complex

Question 16

How many Carbons in Acetyl-CoA

Answer 16

2 Carbon Compound

Question 17

In Step 1 Reacton what is being generated

Answer 17

Molecule of CO2 & NADH is generated

Question 18

In Step 2: Acetyl CoA combines with what Intermediate

Answer 18

Oxaloacetate (4 Carbon Molecule)

Question 19

What intermediate is formed once Acetyl CoA combines with Oxaloacetate

Answer 19

Citrate (6 Carbon Molecule)

Question 20

Combining of Acetyl CoA & Oxaloacetate to form Citrate is catalyzed by what Enzyme

Answer 20

Citrate Synthase

Question 21

Citrate is isomarized into what intermediate

Answer 21

Isocitrate

Question 22

What Enzyme isomarizes Citrate into Isocitrate

Answer 22

Aconitase

Question 23

Isocitrate is then oxidized into what?

Answer 23

Alph-Ketoglutamate (5 carbon compound)

Question 24

What Enzyme is used to irreversibly oxidize decarboxylation of Isocitrate into Alpha-Ketoglutamate

Answer 24

Isocitrate Dehydrogenase
Rate limiting step
Enzyme is allosterically activated by ADP (low energy signal) & CO2 inhibited by ATP & NADH

Question 25

In the reaction between Isocitrate and Alpha- Ketoglutamate..what products are being reduced and generated

Answer 25

In this reaction: | A molecule of NAD+ is reduced into NADH & a molecule of CO2 is generated

Question 26

What is Apha-Ketoglutamate converted into

Answer 26

Succinyl-CoA (4 Carbon Compound)

Question 27

What enzyme is used to convert Apha-Ketoglutamate into Succinyl-CoA

Answer 27

Alpha-Ketoglutarate Dehydrogenase

Question 28

In the reaction between Alpha-Ketoglutamate & Succinyl-CoA...what product is being lost or gained

Answer 28

1 Molecule of Carbon in lost into CO2 | Molecule of NAD+ is reduced to NADH & molecule of CO2 is released

Question 29

Succinyl-CoA is converted into what ?

Answer 29

Succinate

Question 30

What Enzyme is used to convert Succinyl-CoA to Succinate?

Answer 30

Succinil CoA Synthase

Question 31

In the reaction between Succinyl-CoA & Succinate...what molecules are reduced or generated?

Answer 31

A molecule of GTP is generated | GTP + ADP --- GDP + ATP

Question 32

What is GTP

Answer 32

Guanosine Triphosphate Has a ribose sugar and 3 phosphates Involved in energy transfer within the cell

Question 33

What is Succinate oxidized to

Answer 33

Fumarate

Question 34

What Enzyme is used to convert Succinate into Fumarate

Answer 34

Succinate Dehydrogenase

Question 35

In the reaction between Succinate and Fumarate...what molecules are being generated or reduced

Answer 35

As FAD (its coenzyme) is reduced to FADH2

Question 36

What is Fumarate hydrated to

Answer 36

Malate | Freely reversible reaction

Question 37

What Enzyme is used to catalyze Fumarate into Malate

Answer 37

Fumarase

Question 38

What is Malate oxidized to

Answer 38

Oxaloacetate

Question 39

What is the last step of TCA cycle?

Answer 39

The conversion of Malate into Oxaloacetate

Question 40

What Enzyme is used to convert Malate into Oxaloacetate

Answer 40

Malate Dehydrogenase

Question 41

In the conversion of Malate into Oxaloacetate...what products are being generated or reduced

Answer 41

NAD+ is reduced into NADH | Reacton is positive, however rxn is driven in the direction of OAA by the highly exergonic Citrate Synthase reaction

Question 42

What are the Single generated results of the Kreb Cycle

Answer 42

3 Molecules of NADH 1 FADH2 1 GTP 2 CO2

Question 43

Since Glucose is split into 2 Pyruvate Compounds for each molecule of Glucose this Cycle has to run how many times and what are the Final Generated Compounds

Answer 43

``` Cycle runs X2: generating 6 Molecules of NADH 2 FADH2 2 GTP 4 CO2 Number of ATP produced= 12 ATP/Acetyl CoA oxidized ```

Question 44

What happens to the FADH2 & NADH generated compounds

Answer 44

Both compounds are sent to the Electron Transport Chain for generation of ATP

Question 45

What is PDH

Answer 45

Pyruvate Dehydrogenase A multienzyme complex...contains 5 coenzymes that acti as carriers or oxidants for the intermediates PDH supplies Substrate for TCA cycle

Question 46

What are the ramifications if PDF is inactive?

Answer 46

Brain cells are unable to produce sufficient ATP (via TCA Cycle) therefore causing serious Centra Nervous System issues.

Question 47

What is the medical condition caused as a result of inactive PDF and insufficient ATP formation in the CNS

Answer 47

Wernicke-Korsakoff : Encephalopathy-psychosis syndrome due to Thiamine & Niacin Deficiency Additionally : Alcohol abuse

Question 48

Pyruvate is a potent inhibitor of

Answer 48

PDH kinase

Question 49

Calcium (CA2+) is a strong activator of

Answer 49

PDH Phospatase

Question 50

What happens in Pyruvate Dehydrogenase complex deficiency

Answer 50

The inability to convert Pyruvate to Acetyl CoA...causing Pyruvate to be shunted to lactate via lactate Dehydrogenase- causing issues for the brain

Question 51

What are the symptoms of Pyruvate Dehydrogenase deficiency

Answer 51

Variable symptoms, including Neurodegeneration: muscles spasticity, and in the neonatal onset form, early death. X linked dominant (X linked since both M & F are affected) No treatment Dietary restrictions to Carbohydrates & supplementation with thiamine may reduce symptoms in selected pt's

Question 52

Leigh Syndrome

Answer 52

Subacute necrotizing encephalomyelopathy a reare progressive neurodegenerativ edisordeer cause by defects in mitochondrial ATP production primarily as a result of mutation in genes nota code for proteins of PDH complex the electron transport chain or ATP synthase. Both nuclear and mitochondrial DNA can be affected

Question 53

Lipoamide

Answer 53

Lipoamide is an intermediate in glycolysis/gluconeogenesis, citrate cycle (TCA cycle), alanine, aspartate and pyruvate metabolism, and valine, leucine and isoleucine degradation It is generated from dihydrolipoamide via the enzyme dihydrolipoamide dehydrogenase