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Flashcards in TCA cycle Deck (34):
1

What is human respiration

Inhalation of oxygen from atmosphere; exhalation of CO2 and water

2

What is cellular respiration

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

3

Glucogenic aa enter the:

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

4

Ketogenic aa covert to

covert to acetyl CoA

5

What is the first stage of energy production

AcetylCoA can be produced f rom carbs, fats or proteins

6

What is the second stage of energy production

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

7

What is the third stage of energy production

Reducing equivalents generate a proton gradient used to drive ATP synthesis

8

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

amphibolic

9

PDH has 5 cofactors from 4 vitamins:

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

10

pyruvate converts to acetyl CoA via

pyruvutae dehydrogenase

11

What are the enzymes that make up PDH

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

12

Lipoate is a biological tether component of:

E2

13

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

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

14

Aresenite complexes with ___

lipoate

15

Coenzyme is A is a component of

E2

16

FAD and NAD+ is a component of

E3

17

Riboflavin deficiency causes

angular cheilosis

18

Pyruvate dehydrogenase uses substrate _____

channeling;

19

What are the steps of pyruvate dehydrogenase

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

20

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

NAD+; acetyl CoA and NADH

21

How do we regulate pyruvate dehydrogenase

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

22

What are the steps of the TCA cycle

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

23

Where does TCA cycle occur

Occurs in mitochondrial matrix

24

What are the end products

2 CO2's
3 NADH's
1 FADH2
1 GTP

25

What is substrate level phosphorolation

making ATP or GTP without using electron transport chain

26

4 dehydrogenase reactions yield

3 NADH and 1FADH2

27

First half steps of TCA are ____while second half is

irreversible; reversible

28

Aconitase has a ____center

Fe-S; important in iron metabolism

29

Which compounds downregulate the TCA cycle

ATP, NADH, citrate, succinylCoA

30

Which compounds upregulate TCA

ADP, Ca++

31

What is the glycerol phospahte shuttle

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

32

From alpha ketoglutarate we can get:

gluatamate--> argenin, proline, glutamine

33

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

Pyruvate carboxylase

34

What are some TCA enzyme mutations

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