TCA cycle

Question 1

What is human respiration

Answer 1

Inhalation of oxygen from atmosphere; exhalation of CO2 and water

Question 2

What is cellular respiration

Answer 2

Oxidation of acetate to CO2; reduction of O2 to H2O; this occurs in the mitochondria

Question 3

Glucogenic aa enter the:

Answer 3

TCA cycle; they can go around the TCA cycle and go into oxaloacetate which is one of the starting point for gluconeogenesis

Question 4

Ketogenic aa covert to

Answer 4

covert to acetyl CoA

Question 5

What is the first stage of energy production

Answer 5

AcetylCoA can be produced f rom carbs, fats or proteins

Question 6

What is the second stage of energy production

Answer 6

Generates reducing equivalents for electron transport in the form of NADH and FADH2

Question 7

What is the third stage of energy production

Answer 7

Reducing equivalents generate a proton gradient used to drive ATP synthesis

Question 8

The TCA cycle is _____; important in both anabolic and catabolic processes

Answer 8

amphibolic

Question 9

PDH has 5 cofactors from 4 vitamins:

Answer 9

1. Thiamine -TPP (vit B1)
2. Riboflavin -FAD (vit B2)
3. Niacin- NAD+ (vit B3)
4. Panthothenate- Coenzyme A (Vitamin B5)
5. Lipoate

Question 10

pyruvate converts to acetyl CoA via

Answer 10

pyruvutae dehydrogenase

Question 11

What are the enzymes that make up PDH

Answer 11

1. E1: pyruvate dehydrogenase
2. E2: Dihydrolipoyle Transacetylase
3. E3: Dihydrolipoyle Dehydrogenase

Question 12

Lipoate is a biological tether component of:

Answer 12

E2

Question 13

E2 has functional domains conn by 20-30 aa linkers:

Answer 13

1. NH2 terminal: lipoyl domain
2. Central: E1 and E3 binding domain
3. Inner core: acyltransferase domain

Question 14

Aresenite complexes with ___

Answer 14

lipoate

Question 15

Coenzyme is A is a component of

Answer 15

E2

Question 16

FAD and NAD+ is a component of

Answer 16

E3

Question 17

Riboflavin deficiency causes

Answer 17

angular cheilosis

Question 18

Pyruvate dehydrogenase uses substrate _____

Answer 18

channeling;

Question 19

What are the steps of pyruvate dehydrogenase

Answer 19

1. Decarboxylate CO2 and transfer to thiamine which transfers to lipoalysine carrier form which becomes reduced after we attach the acetyl group to it.
2. Transfers to coenzyme A molecule which bec released
3. Make acetyl CoA
4. regenerate enzyme to its active form. Lipolysine now needs to be reoxidized which happends through FAD.
5. Now we reoxideze FAD to FADH via NAD

Question 20

If our starting point are pyruvate and ____our end products are:

Answer 20

NAD+; acetyl CoA and NADH

Question 21

How do we regulate pyruvate dehydrogenase

Answer 21

ATP and NADPH are signals to slow down Pyruvate dehydrogenase. Acetyl CoA is end product inhibitor.

Question 22

What are the steps of the TCA cycle

Answer 22

1. Condense carbons to oxaloacetate which condenses with acetyl CoA to make citrate
2. Dehydrate/rehydrate via aconitase to make isocitrate
3. Dehydrate carbons and rearrange to alpha ketoglutarate via isocitrate dehydrogenase
4. Alpha kegolutarate dehydrogenase complex makes it lose another C02 and form succinyl CoA which has 4 carbons
5. This converts to succinate where we get substrate level phosphorolation of GTP
6. Make DB which makes fumerate and FADH2
7. Hydrate DB to make malate
8. Oxidize hydroxyl to make a keto –> oxaloacetate and NADH

Question 23

Where does TCA cycle occur

Answer 23

Occurs in mitochondrial matrix

Question 24

What are the end products

Answer 24

2 CO2’s
3 NADH’s
1 FADH2
1 GTP

Question 25

What is substrate level phosphorolation

Answer 25

making ATP or GTP without using electron transport chain

Question 26

4 dehydrogenase reactions yield

Answer 26

3 NADH and 1FADH2

Question 27

First half steps of TCA are ____while second half is

Answer 27

irreversible; reversible

Question 28

Aconitase has a ____center

Answer 28

Fe-S; important in iron metabolism

Question 29

Which compounds downregulate the TCA cycle

Answer 29

ATP, NADH, citrate, succinylCoA

Question 30

Which compounds upregulate TCA

Answer 30

ADP, Ca++

Question 31

What is the glycerol phospahte shuttle

Answer 31

skeletal, muscle, brain; uses cytosolic and mitochondrial glycerol 3 P dehydrogenase

Question 32

From alpha ketoglutarate we can get:

Answer 32

gluatamate–> argenin, proline, glutamine

Question 33

Anapleurotic reactions replenish pathway intermediates ; most impt is the ____ which produces oxaloacetate

Answer 33

Pyruvate carboxylase

Question 34

What are some TCA enzyme mutations

Answer 34

Fumerase: kidney and smooth muscle
Succinate dehydrogenase: adrenal gland; over produce epinephrine
-Both of these 2 build up and activates a transc factor: Hif1a (important in tumors, need new blood vessels to be made); stimulates glycolytic enzyme synthesis