Acetyl CoA and the CAC

Question 1

What is the metabolic fuel for the CAC?

Answer 1

acetyl CoA

Question 2

acetate+coenzyme A =?

Answer 2

acetyl CoA

Question 3

What 3 things make up coenzyme A?

Answer 3

1. AMP with extra P group attached to ribose
2. phosphorylated pantothentic acid (B5)
3. mercaptoethyalimine

Question 4

The reduced thiol (SH) in coASH can react with what to form what type of linkages?

Answer 4

react with carboxyl groups to form thioester linkages

Question 5

Acetyl Coa can be formed from what 3 things? Acetyl Coa in turn can be used for what 4 processes?

Answer 5

carbs, lipids, amino acids

1. CAC
2. Fatty acid biosynthesis: TAG, Phospholipids
3. Ketone Body formation
4. Cholesterol biosynthesis: steroid hormones, bile acids, vit D

Question 6

Biochemical reaction for oxidative decarboxylation of pyruvate?

Answer 6

Pyruvate + NAD+ + COASH –> PDH –> acetyl CoA + NADH + CO2 + H+

Question 7

What 3 enzymes make up the PDH complex?

Answer 7

pyruvate decarboxylate: (Ena)
dihydrolipoyl transacetylase (Enb)
dihydrolipoyl DH (EnC)

Question 8

What is vitamin B1?

Answer 8

thiamine

Question 9

Where is the PDH complex located?

Answer 9

mitochondrial matrix

Question 10

Where is the pyruvate from glycolysis generated?

Answer 10

in the cytosol

Question 11

Where is the protein translocase for pyruvate located?

Answer 11

in the inner mit membrane

Question 12

What are the 5 coenzymes for the PDH complex?

Answer 12

2 soluble: Coa and NAD+

3 tighly bond: TPP, lipoamide, FAD

Question 13

What 4 B vits are required for PDH complex?

Answer 13

1. Pantothenic acid (B5) - CoAsh
2. Thiamin (B1) - TPP
3. Niacin (B3)- NAD+
4. Riboflavin (B2) (FAD)

Question 14

What is riboflavin required for?

Answer 14

it is B2.. and FAD needs it

Question 15

What is B2?

Answer 15

riboflavin

Question 16

What B vitamin does NAD+ require?

Answer 16

niacin

Question 17

Draw out the steps of the CAC!!! anddddd GO :)

Answer 17

:)

Question 18

What 3 steps produce NADH?

Answer 18

3. isocitrate + NAD+ –> isocit DH –> aKG + NADH+CO2+H
4. aKG + CoASH+ NAD+ –> aKG DH –> succinyl-COA + CO2 + NADH+ H+
5. malate + NAD+ –> mal DH –> OAA + NADH + H

Question 19

What CAC step produces GTP?

Answer 19

5. succinyl-COA + GDP –> succinyl COA synthetase –> succinate + GTP

Question 20

What step in the CAC utilizes water?

Answer 20

7. Fumurate + H20 –> fumarase –> malate

Question 21

CO2 is produced in what 2 steps?

Answer 21

3. isocitrate + NAD+ –> iso DH –> aKG + NADH + CO2 + H+

4. aKG + CoASH + NAD+ –> akg DH –> sucinnyl COA + NADH + H+ CO2

Question 22

What step in the CAC produces FADH?

Answer 22

6. succinate + FAD –> suc DH –> fumurate + FADH2

Question 23

How many ATP are produced from the CAC?

Answer 23

12 ATP total

11 from Oxidative Phos:
3 NADH produced –> 3 x 3 ATP : 9 ATP
1 FADH2 produced –> 1 x 2 ATP: 2 ATP

1 ATP from substrate-level Phosphorylation

Question 24

How many ATPS can be produced from each molecule of Pyruvate?

Answer 24

15 ATP

Question 25

How many ATPS can be formed from each glucose molecule?

Answer 25

30 ATP

Question 26

Citrate can be utilized to make what?

Answer 26

acetyl coa --> fatty acids: sterols

Question 27

AKG can make what?

Answer 27

Glutamate --> amino acids (purines)

Question 28

Succinyl-CoA can make what?

Answer 28

porphyrins (hemes, cytochromes)

Question 29

malate can be used to make what?

Answer 29

Pyruvate--> alanine

Question 30

OAA can make what?

Answer 30

Phosphoenolpyruvate --> Glucose | Aspartate --> AA, urea, purines, pyrimidines

Question 31

Aspartate can be made from what CAC product?

Answer 31

OAA

Question 32

What CAC product can make glutamate?

Answer 32

a-KG

Question 33

What CAC product can indirectly make alanine?

Answer 33

malate

Question 34

What 2 anaplerotic reactions are used to replenish OAA?

Answer 34

1. Pyruvate + ATP + HCO3 --> pyr carboxylase --> OAA | 2. Glutamate + NAHP" --> Glutamate DH-->a-KG + NADPH + NH4

Question 35

Pyruvate carboxylase requires what B vitamin?

Answer 35

biotin!!

Question 36

The PDH complex is inactivated by what process and what 4 things?

Answer 36

inactivated via phosphorylation (kinase) acetyl-CoA NADH ATP fatty acids

Question 37

The PDH complex is activated by what process and what 4 things?

Answer 37

activated via dephosphorylation pyruvate NAD+ ADP CoASH

Question 38

What 2 enzymes are regulated in the CAC?

Answer 38

isocitrate DH | a-KG DH

Question 39

Isocitrate DH is regulated by what?

Answer 39

+ by ADP | - NADH

Question 40

a-KG is regulated by what?

Answer 40

- succinyl-Coa and NADH

Question 41

Although a-KG complex is similar the the PDH complex is it not regulated by what processes?

Answer 41

phos/dephos

Question 42

PDH deficiency?

Answer 42

defects cause chronic lactic acidosis; this is because the pyruvate produced is reduced by NADH to lactate

Question 43

Thiamine deficiency?

Answer 43

B1 deficiency: required by both PDH and aKG; elderly and the poor are susceptible; and alcoholics; loss of appetite, constipation, nausea, fatigue, mental depression and peripheral neuropathy; and wernicke korsakoff syndrome

Question 44

Beri-beri?

Answer 44

polished rice diets; dry: no fluid retention wet: edema and cardiac failure -beri beri can present with serum lactic acidemia

Question 45

What will result from CAC deficiencies?

Answer 45

serum lactic acidemia

Question 46

What are 3 ketone bodies that are formed in fasted and starvation in uncontrolled type 1 diabetes?

Answer 46

1. acetoacetate 2. b-hydroxybutyrate 3. acetone