citric acid cycle

Question 1

stage one of citric acid cycle is

Answer 1

acetyl coA production

Question 2

pyruvate undergoes ____ ___ to produce acetyl co a

Answer 2

oxidative decarboxylation

Question 3

the citric acid cycle occurs in

Answer 3

mitochondrial matrix

Question 4

within step one of aerobic respiration (citric acid cycle) there are ___ seperate enzymatic activities and _ cofactors

Answer 4

3, 5

Question 5

what are the five cofactors

Answer 5

TPP, NAD, lipoate, FAD, Coa-SH

Question 6

catabolic

Answer 6

breaking down

Question 7

NAD is an electron carrier and carries __ electrons

Answer 7

2

Question 8

TPP does what two actions

Answer 8

C-C bond cleavage and two carbon transfer

Question 9

there are three major steps of respiration what are they

Answer 9

1. acteyl co a production
2. acetyl co a oxidation
3. electron transfer and oxidative phosphorylation

Question 10

respiration is all about pushing ___

Answer 10

electrons

Question 11

with acetyl coa procution by pyruvate there is what relwased

Answer 11

co2

Question 12

the enzyme complex used to convert pyruvate to acetyl coa is

Answer 12

pyruvate dehydrogenase complex (has three subunits)

Question 13

pyruvate dehydrogenase complex has ____ ____ in which intermediated never leave the complex

Answer 13

substrate channeling

Question 13

lipoate is convently bound to a ____ on E2; the result is

Answer 13

lysine; lipoamide

Question 14

FAD is an ___ ____

Answer 14

electron acceptor

Question 15

E2 has two domains, lysine to which the lipoate is attached is in one but the the other is an ____

Answer 15

active site

Question 16

lipoate can exist in three states

Answer 16

1. oxidized
2. reduced
3. acetylated

Question 17

lipoate can carry ___ and ____

Answer 17

electrons and acetyl co a

Question 18

FAD cannot ____ it is present and attached to E3 subunit

Answer 18

leave (NAD can move in and out )

Question 19

coezyme A carries ____ groups; has a reactive thiol group

Answer 19

acetyl

Question 20

TPP has an _____ _____ which readily leaves

Answer 20

acidic proton

Question 21

once the proton leaves the E1 TPP will readily attack the incoming carbonyl carbon of ___; which releases CO2

Answer 21

pyruvate

Question 22

the remaing part of the pyruvate on TPP gets converted to _____

Answer 22

hydroxyethyl TPP

Question 23

The E2 lipoamide has a lysine amino acid linker which will swing into E1 and coverted that group in E1 to what

Answer 23

acytelated lipoamide

Question 24

next in E2 subunit CoA will diffuse in and pick up acetyl group to become

Answer 24

acetyl CoA

Question 25

the reduced lipoamide drops off electrons to FAD (E3) making it

Answer 25

FADH2

Question 26

NAD will pick up electrons from FADH2 and becomes

Answer 26

NADH2

Question 27

Once pyruvate is converted to Acetyl CoA it is irreversible but Acetyl CoA can either go to ___ __ __ or _ _ _

Answer 27

citric acid cycle or fatty acid synthesis

Question 28

high levels of ATP would cause Acetyl CoA to choose

Answer 28

fatty acid synthesis

Question 29

The PDH complex is alosterically regulated by __ ____ and ___

Answer 29

AMP, CoA and NAD+

Question 30

The PDH complex is ___ by dephosphorylation of E1

Answer 30

activated

Question 31

stage 2 of the citric acid cycle uses 2C (acetyl coa) which enters and combines with ____

Answer 31

4C oxaloacetate

Question 32

used in both anabolic and catabolic processes; intemediates leave/join at different points

Answer 32

amphibolic (citric acid cycle does this)

Question 33

the 6C molecule formed from acetyl coA and oxaloacetate is

Answer 33

citrate

Question 34

step one is a condensations step where acetyl coA and oxaloacetate are are combined. What enzyme is used? which gives you?

Answer 34

citrate synthase; citrate

Question 35

step 2 is generating a better substrate for step 3; which ___ to ____

Answer 35

citrate to isocitrate

Question 36

citrate is a ____ alcohol which makes it a poor substrate for oxidation

Answer 36

tertiary

Question 37

the intermediate between citrate and isocitrate is

Answer 37

cis-aconitate

Question 38

____ is the enzyme which helps use water to change citrate to isocitrate

Answer 38

aconitase

Question 39

_____ of the citrate leads to cis C double bond C

Answer 39

dehydration

Question 40

step 3 is the first oxidation in which isocitrate becomes oxidized by ____

Answer 40

NAD

Question 41

step 3 is catalyzed by ____ ____ and requires manganese ion to stabilize

Answer 41

isocitrate dehydrogenase

Question 42

isocitrate is converted to ____ by NAD (oxidation) then to ____ with release of (decoarboxylation)

Answer 42

oxalosuccinate; alpha ketoglutarate

Question 43

step 4 is the second oxidation where alpha ketoglutarate gets converted to ____ ____ (oxidative decarboxylation)

Answer 43

succinyl-CoA

Question 44

step 3 ends in succinyl-CoA which results in high group transfer potential with ___

Answer 44

thioester

Question 45

step 5 is a substrate level phosphorylation where succinyl coA becomes _____

Answer 45

succinate

Question 46

step 5 generates ____

Answer 46

GTP

Question 47

catalyzes condensation reactions using energy of NTPs

Answer 47

synthetase

Question 48

what enzyme converts succinyl coA into succinate (enzyme is not named correctly; typically there will be a breakage or cleavage yet that does not happen)

Answer 48

succinyl-CoA synthetase

Question 49

step 5 also produces a ____

Answer 49

GTP

Question 50

all triphosphates are essentially ____ and interconvertible in terms of energy

Answer 50

equal

Question 51

step 6 is the third oxidation in which succinate is converted to ____

Answer 51

fumarate

Question 52

what enzyme is used for step 6

Answer 52

succinate dehydrogenase

Question 53

step 6 is the only reaction in which ____ is the electron acceptor

Answer 53

FAD

Question 54

succinate dehydrogenase is the only enzyme not in the ___; it is bound to inner mitochondrial matrix

Answer 54

matrix

Question 55

step 7 is hydration where fumarate becomes ____ (uses fumarase as enzyme)

Answer 55

malate

Question 56

within step 7 addition of water occurs in two steps what are they

Answer 56

1. hydroxylation generates a carbanion 2. protonation neutralizes the carbanion

Question 57

fumarase only adds water in ___ across the double bond

Answer 57

trans

Question 58

step 8 is an oxidation where you go from L-malate to (high G- unfavorable; product removal pushes it forward!)

Answer 58

oxaloacetate

Question 59

in step 8 ___ is the electron acceptor and the enzyme is

Answer 59

NAD, and malate dehydrogenase

Question 60

one ___ is produced per cycle

Answer 60

GTP

Question 61

electrons from cirtic acid cycle REDUCE NAD+ and FAD; which are then used to make ATP there are ___ ATP per FADH2 and ___ ATP per NADH

Answer 61

1.5, 2.5

Question 62

every 4 protons gives you one ATP and NADH pushed ten protons so ___ ATP per NADH

Answer 62

2.5

Question 63

alpha ketoglutarate can leave pathway and make ___

Answer 63

purines

Question 64

pyruvate can make oxaloacetate to make aspartate which makes

Answer 64

amino acids, purines and pyrimidines

Question 65

the ____ reaction is when pyruvate will bind to bicarboinate in presence of ATP and ezyme is ___ will give you oxaloacetate to run citric acid cycle (you have to have it!!)

Answer 65

analplerotic; pyruvate carboxylase

Question 66

the anaplerotic reaction will replenish ___ for the cycle

Answer 66

metabolites

Question 67

pyruvate carboxylase wont function unless acetyl coA is abundant, why?

Answer 67

acetyl coA will build up and will activate oxaloacetate which can then make citrate

Question 68

high acetyl coA negatively regulated PDH; why?

Answer 68

high acetyl CoA shows a fed state so don't need to run citric acid cycle