citric acid cycle

Question 1

what are the reactants and products of the TCA

Answer 1

pyruvate+ CoA + NAD+= acetyl co a + co2 + nadh

Question 2

what vitamin does coa come from

Answer 2

b5 pantothenate

Question 3

what bond does coA have

Answer 3

thioester high energy bond

Question 4

wht does CoA do

Answer 4

carrier of acyl gps

Question 5

what cofactors does PDH use

Answer 5

TPP
CoAsh
Lipoic Acid
FAD
NAD
the coons like fighting niggas

Question 6

describe TPP location and function

Answer 6

• catalytic
• bound to E1
• decarboxylates pyruv

Question 7

describe lipoic acid and its loc and func.

Answer 7

• catalytic
• inked to lys on e2 (lipoamide)
• ## accepts hydroxyethyl carbanion from tpp

Question 8

coenzyme A

Answer 8

stochiometric
- substrate for E2
- accepts aceytl group from lipoamide

Question 9

FAD flavin

Answer 9

• bound to E3
• reduced by lipoamide

Question 10

NAD+ catalutic

Answer 10

substrate for E3
reduced by FADH@

Question 11

Q: What metabolic enzyme does arsenite primarily inhibit?

Answer 11

inhibits pyruvate

Question 12

what is the first enzyme of tca

Answer 12

citrate synthase
- add acetyl group to oxalocacetate to make citrate

Question 13

why is succinyl coa synthetase important

Answer 13

• uses SLP
• nucleoside triphosphate is made - atp in most prok
• gtp in euk
• driven by hydrolysis of CoA ester
• inolves phosphohistidine

Question 14

succinate DH is competitively inhibited why what

Answer 14

malonate making it poison

Question 15

what is the only enzyme bound of TCA

Answer 15

succinate DH bc its complex 2 of the ETC

Question 16

what happens during succinate dh

Answer 16

• hydride transfer and oxidation with fad
• fad reduced

Question 17

what are the characteristics of riboflavin vitamin b12

Answer 17

• coenzyme: FAD, FMN
• oxidation reduction
  growth retardation

Question 18

why is fumarase a bidrecrtional rxn

Answer 18

• lyase reaction
• prochiral differentiation= molecule that is not chiral has the potential to become chiral

Question 19

what is the product of tca in euk

Answer 19

• 2 co2
• 1 gtp= atp equivalent
• 3 nadh
• 1 fadh2
  -(4 reduced coenzues)

Question 20

how is pyruvate dh regulated

Answer 20

producut inhibition by NADH Nad+ for binding sites e3
-acetyl w/ CoA for binding site e2

Question 21

what does Pyr. DH do to enzymes E2 and E3

Answer 21

• drive them backwards
• keeps E2 in acetylated form unable to accept hydroxyethyl gp from E1

Question 22

how to control phosphorylation

Answer 22

• phosphoryl of side chain OH,S,T,Y residues or imidazole= N of His
• transfer of ATP
• causes cascades of one kinase to another
• amplify signals

Question 23

which enzyme is used by reversible phosphorylation of pyruvate DH

Answer 23

enzyme 1
- deacitvated by PDH kinase

Question 24

what activatdes PDH kinase

Answer 24

• acetyl co a, nadh/Nad+, or ATP
  this leads to the deactivation

Question 25

when does PDH switch off

Answer 25

when the energy is high and biosynthetic intermediates are high

Question 26

what keeps PDH kinase active

Answer 26

- pyruvate, ADP, Ca+2 - low signal = make atp

Question 27

enzyme 1 is activated by what in regulation of pDH

Answer 27

-dephosphorylation PDH phophatase

Question 28

what are some main points of TCA and PDH rxn

Answer 28

1. occurs in mito matrix except for succinate DH( membrane bound) 2. PDH, citrate synthasae, isocitrate dh, alpha keto dh = irrreversible 3. irreversible = regulated

Question 29

what are the main regulatory enzymes of tca

Answer 29

- isocitrate DH - PDH

Question 30

which rxns are inhibited by NADH and ATP

Answer 30

- pdh -citrate synthase - isocitate - alpha keto dh

Question 31

what is the enzyme that makes cycle underectional

Answer 31

alpha keto dh

Question 32

what does succinal co a synthetase use to generate atp

Answer 32

SLP

Question 33

what are the anaplerotic reactons and what is anaplerotic

Answer 33

- replenishes intermediates - Pyruvate carb -PEP carboxy - malic enzyme

Question 34

what does pyruvate carb do

Answer 34

- converts pyruvate to oxalocae found in liver, kidney

Question 35

what does pep carboxy do

Answer 35

converts PEP --> oxalocaetate - higher in plants, yeast, bacteria not animals

Question 36

what does malic enzyme do

Answer 36

pyruv--> malate widely distributed by prok and euk

Question 37

what is the role of aspartate transaminase in tca

Answer 37

facilitates the conversion of aspartate ito oxalocaetate , linking nitrogen metabolish with central carbon metabolism

Question 38

what is the first enzyme of gluconeogenesis

Answer 38

pyruvate carboxylase

Question 39

what does pyruv carbox do again

Answer 39

- catalyzes the atp and biotin dependent conversionof pyr to oxalocatee in mitochondrial matrix

Question 40

what happens to carboxyl c of acetate

Answer 40

turns into co2 in the second turn of the cycle