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MedBiochem > quiz 2.2 glyco, gluconeo, TCA > Flashcards

quiz 2.2 glyco, gluconeo, TCA Flashcards

1
Q

how many rxns sa glycolysis

A

10

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2
Q

ano phases ng glycosis

A

energy-investing/preparatory

pay-off phase

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3
Q

the energy-investing phase involves which rxns

A

first 5

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4
Q

in the energy-investing phase, glucose results to

A

2 moles of glyceraldehyde-3-PO4

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5
Q

the first priming rxn of glycolysis

A

phosphorylation of glucose

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6
Q

in the first step, glucose is irreversibly phosphorylated to _________ by the enzyme _____

A

gulocse-6-PO4

hexokinase

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7
Q

where is gluc-6-PO4 trapped

A

cytsol

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8
Q

these isoenzymes of hexokinase can phosphorylate other hexoses aside from glucose

A

hexokinase 1 2 3

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9
Q

hexokinase isoenzyme with low Km thus high affinity for glucose

A

hexokinase 1 2 3

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10
Q

the predominant isoenzyme of hexokinase in the liver and pacnreas

A

hexokinase 4 (glucokinase)

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11
Q

this isoenzyme becomes functional only during periods of high level of glucose

A

glucokinase

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12
Q

gluckinase has ____ kM thus requiring _____

A

higher

higher

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13
Q

where is glucokinase found

A

parenchymal cells in liver

beta cells in pancreas

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14
Q

which enzyme is inhibited by gluc-6-PO4

A

hexokinase

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15
Q

2nd step of the glycolysis pathway

A

isomerization of gluc-6-PO4

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16
Q

in the 2nd step, gluc-6-PO4 is isomerized to _____ by

A

fructose-6-PO4

phosphoglucose isomerase

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17
Q

third step of glycolysis

A

phophorylation of fruc-6-PO4

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18
Q

in the 3rd step, fruc-6-PO4 is phosphorylated to ________ by _______

A

fructose-1,6-bisphosphate

phosphofructokinase (PFK-1)

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19
Q

the rate limiting step, commited step and most important point in glycolysis

A

phosphorylation of fruc-6-PO4 to fruc-1,6-bisPO4

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20
Q

what is the rate limiting enzyme

A

PFK-1

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21
Q

what are the shits that control the activity of PFK-1

A

energy w/in cell

regulatory substrates

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22
Q

___________ of ATP in the cell allosterically inhibits PFK-1

A

elevated levels

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23
Q

__________________, signaling depletion of the cell’s energy stores, allosterically activates PFK-1

A

high conc of AMP

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24
Q

an intermediate of the TCA cycle that inhibits PFK-1

A

citrate

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25
Q

the most potent allosteric activator of PFK-1 that can oppose inhibition by high levels of ATP

A

fructose-2,6-bisPO4

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26
Q

fructose-2,6-bisPO4 formation is catalyzed by

A

PFK-2

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27
Q

PFK-2 is a bifunctional enzyme that has what activities

A

kinase and phosphatase acivity

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28
Q

in the liver, which PFK-2 domain is active if dephosphorylated

A

kinase

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29
Q

which domain of PFK2 catalyzes fruc-2,6-bisPO4 to fruc-6-PO4

A

phosphatase

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30
Q

which domain of PFK2 catalyzes fruc-6-PO4 to fruc-2,6-bisPO4

A

kinase

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31
Q

acts as an intracellular signaling indicating that glucose is abundant

A

fruc-2,6-bisPO4

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32
Q

after a well-fed state, what cause an increase in fruc-2,6-bisPO4

A

dec. glucagon

elev. insulin

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33
Q

in the fasted state, PFK-2 is ____________ there it is rendered _______

A

phosphorylated

inactivated

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34
Q

4th step in glycolysis

A

cleavage of fruc-1,6-bisPO4 to DHAP and glyceraldehyde-3-PO4

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35
Q

in the 4th step, fuctose-1,6-bisPO4 is cleaved to __________ by ________

A

dihydroxyacetone and glyceraldehyde-3-PO4

aldolase

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36
Q

5th step of glycolysis/last step of the energy-investing phase

A

isomerization of DHAP

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37
Q

end product after 5th step of glycolysis

A

2 moles of glyceraldehyde-3-phosphate

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38
Q

in the 5th step, DHAP is interconverted to _______ by ________

A

glyceraldehyde-3-PO4

triose phosphate isomerase

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39
Q

this phase includes the energy-conserving phosphorylation steps in which some of the chemical energy of the glucose molecule of conserved in the form of ATP and NADH

A

pay-off phase

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40
Q

in the pay-off phase, how many molecules of ATP are formed in the substrate-level phosphorylation per glucose molecule metabolized

A

2

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41
Q

this is the first redox rxn of glycolysis

A

6th step

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42
Q

6th step of glycolysis

A

oxidation of glyceraldehyde-3-PO4

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43
Q

what happens sa first redox rxn ng glycolysis

A

glyceraldehyde-3-PO4 is conerted to 1,3-bisphosphoglycerate by glyceraldehyde-3-PO4 dehydrogenase

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44
Q

in the 6th step, glyceraldeyhde-3-PO4 is converted to _______ by ____

A

1,3-bisphophoglycertae

glyceraldehyde-3-PO4 dehydrogenase

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45
Q

which part of 1,3-BPG conserves the free energy produced by the oxidation

A

the phosphate group @ C1

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46
Q

the NADH produced during 6th step must be

A

reoxidized back to NAD to replenish its limited supply

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47
Q

2 major mechanisms of oxidizing NADH

A

coversion pf pyruvate to lactate via LDH

oxidation of NADH via ETC

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48
Q

2 substrate shuttles that transport into the mitochondrial matrix

A

glycerophosphate n

malate-aspartate

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49
Q

how many ATPs are formed from each cytosolic NADH pxidized in the glycerophosphate shuttle

A

2

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50
Q

in this shuttle, two electrons are transferred from NADH to DHAP by cytosolic glyceraldehyde-3-PO4 dehydrogenase

A

glycerophosphate shuttle

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51
Q

in this shuttle, two electrons are transferred from NADH to oxaloacetate by cytosolic malate dehydrogenase

A

malate-aspartate shuttle

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52
Q

how many ATPs are formed from each cytosolic NADH pxidized in the malate-aspatate shuttle

A

3

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53
Q

oxaloacetate cannot enter the mitochondria therefore it is converted to

A

malate

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54
Q

in RBCs, some 1,3-BPG are converted to _________ by _____________

A

2,3-BPG

bisphosphoglycerate mutase

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55
Q

in which shunt is 2,3-BPG formed

A

rapoport-luebering pathway

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56
Q

an intermediate formed from 2,3-BPG

A

3-phosphoglycerate

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57
Q

7th step in glycolysis

A

synthesis of 3-phosphoglycerate, producing ATP

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58
Q

in the 7th step, 1,3-BPG is converted to ________ by _______

A

3-phosphoglycerate

phosphoglycerate kinase

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59
Q

in the 7th step, what specifically is used to form ATP

A

the high-energy phosphate group of 1,3-BPG

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60
Q

formation of ATP in the 7th step is via _____________ phosphorylation, where in the needed energy comes from a substrate not the ETC

A

substrate-level

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61
Q

8th step in glycolysis

A

shift of the phosphate group

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62
Q

in the 8th step, 3-phosphoglycerate is converted to _______ by __________

A

2-phosphoglycerate

phosphoglycerate mutase

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63
Q

9th step of glycolysis

A

dehydration of 2-phosphoglycerate

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64
Q

in the 9th step, dehydrtion of 2-phosphoglycerate to ____________ is catalyzed by ________________

A

phosphoenolpyruvate

enolase

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65
Q

10th step of glycolysis

A

formation of pyruvate, producing ATP

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66
Q

what are the 2 ATP producing steps in glycolysis

A

7

10

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67
Q

in the 10th step, PEP is converted to ______ by __________

A

pyruvate

pyruvate kinase

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68
Q

in the 10th step, what specifically is used to form ATP

A

high enery enol phosphate

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69
Q

what are the three irreversible steps in glycolysis

A

1
3
10

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70
Q

puryvate kinase is activated by what

A

fruc-1,6-bisphosphate-

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71
Q

pyruvate kinase is inactivated when

A

fasted state

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72
Q

pyruvate kinase in the liver is inactivated how

A

phosphorylation by a cAMP-dependent protein kkinase

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73
Q

pyruvate is converted to __________ by _______________

A

lactate

LDH

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74
Q

effect of insulin on glucokinase, PFK and PK

A

increased synthesis

75
Q

effect of glucagon on glucokinase, PFK and PK

A

decreased sythensis

76
Q

pyruvate is converted to acetyl CoA by

A

pyruvate dehydrogenase

77
Q

pyruvate is converted to _____________ by pyruvate dehydrogenase

A

acetyl CoA

78
Q

pyruvate is converted to oxaloacetate by

A

pyruvate carboxylase

79
Q

pryvaute is converted to ____ by pyruvate carboxylase

A

oxaloacetate

80
Q

pyruvate is converted to alanine by

A

alanine amino transferase using coenzyme PPP

81
Q

the final common pathway for the oxidation of the major macromolecules

A

TCA

82
Q

resulting product of TCA

A

acetyl CoA

83
Q

the step that provides the substrate for the TCA

A

oxidative decarboxylation of pyruvate by PDH complex

84
Q

3 components enzymes of the PDH complex

A

E1 2 3

85
Q

E1 requires

A

thiamine pyrophosphate

86
Q

E2 requires

A

lipoic acid and coenzyme A

87
Q

E3 requires

A

FAD and NAD

88
Q

E1 aka

A

pyruvate decarboxylase/dehydrogenase

89
Q

E2 aka

A

dihydrolipoyl transacetylase

90
Q

E3 aka

A

dihydrolipoyl dehydrogenase

91
Q

the 2 regulartory enzymes in the PDH complex

A

PDH kinase

PDH phosphatase

92
Q

in pyruvate decarboxylaton, pyruvate is carboxylased to

A

hydroxyethyl derivative bound to TPP

93
Q

in pyruvate decarboxylation, the hydroxyethyl intermediate is tranferred to

A

disulfide form of lipoic acid bound to E1

94
Q

the acetyl group bound as a thioester to the side chain of lipoid acid i tranferred to

A

coenzyme A

95
Q

the sulfhydyl form of lipoic acid is oxidized by ______ leading to the regen of ozidized lipoic acid

A

FAD-dependent E3

96
Q

FADH2 on E3 is reoxidized to ____ and NAD is reduced to ______

A

FAD

NADH and H

97
Q

cAMP-independent PDH kinase ________ and _______ E1

A

phosphorylates and inactivates

98
Q

PDH phosphatase _____ and ____ E1

A

dephosphorylates and activates

99
Q

PDH is also regulated via inhibition by its products _____

A

actyl CoA and NADH

100
Q

pyruvates inhibits which PDH domain

A

PDH kinase

101
Q

calcium activates which PDH domain

A

PDH phosphatase

102
Q

2nd step in TCA

A

isomerization of citrate

103
Q

formation of cirate is caused by

A

citrate synthase

104
Q

citrate is synthesized from

A

acetyl CoA and oxaloacetate

105
Q

inhibitor of citrate synthase

A

citrate

106
Q

this is the rate-limiting enzyme of glycolysis

A

PFK-1

107
Q

in the 2nd step of TCA, isomerization of citrate to ______ is catalyzed by

A

isocitrate

aconitase

108
Q

3rd step of TCA

A

oxidative carboxylation of isocitrate

109
Q

the 3rd step of TCA yields the first ________ and _______

A

NADH

CO2

110
Q

isocitrate dehydrogenase is activated and inactivated respectively by ____ and ______

A

ADP (low energy signal)

ATP (high energy signal)

111
Q

4th TCA step

A

oxidative decarboxylation of alpha ketoglurate

112
Q

in the 4th step, alpha ketoglutarate is converted to ___ by _____

A

succinyl CoA

alpha-ketoglurate dehydrogenase complex

113
Q

the 4th step of TCA yields the ______ and _______

A

second NADH and CO2

114
Q

inhibitors of the alpha-glutarate dehydrogenase complex

A

NADH and succinyl CoA

115
Q

5th step in TCA

A

cleavage of succinyl CoA

116
Q

in the 5th step of TCA, succinyl CoA is cleaved to ___ by ____

A

succinate

succinyl CoA synthetase/succinate thiokinase

117
Q

the cleaveof succinylCOA is coupled with the phosphorylation of _______________ to ______________

A

GDP to GTP

another substrate level phosphrylation

118
Q

6th step in TCA

A

oxidation of succinate

119
Q

in the 6th step, oxidation of succinate to _____ is catalyzed by _____

A

fumarate

succinate dehydrogenase

120
Q

only enzyme of the TCAe mbedded in the inner mitochondrial membrane

A

succinate deydrogenase

121
Q

7th step of TCA

A

hydration of fumarate

122
Q

in the 7th step, fumarate is hydrated to _____ in a freely reversible rxn catalyzed by _____

A

malate

fumarase [hydratase]

123
Q

8th step of TCA

A

oxidation of malate

124
Q

in the 8th step of TCA, oxidation of malate to _____ is catalyzed by ___

A

OXAA

malate dehydrogenase

125
Q

the 8th step of TCA yields the ____ and _____

A

third and last NADH and CO2

126
Q

one cycle of TCA produces how many ATPs

A

12

127
Q

each NADH produced in the TCA corresponds to how many ATPs

A

3

128
Q

each FADH2 produced in the TCA corresponds to how many ATPs

A

2

129
Q

bakit 12 ATPs ang formed sa TCA

A

3 NADH
1 FADH2
1 GTP

130
Q

net ATP produced in the complete aerobic oxidation of glucose via glycolysis, PDH complex rxn, TCA cycle and oxidative phosphorylation in the ETC

A

36-38 ATPs

131
Q

kelan 36 ang ATPs yield

A

kpaag glycerophosphate shuttle ang ginamit

132
Q

kelan 38 ATPs yield

A

kpag malate-aspartate shuttle ang ginamit

133
Q

three most important enzymes when regulated TCA cycle

A

citrate synthase
isocitrate dehydrogenase
alpha-ketoglutarate dehydrogenase complex

134
Q

what is common in the 3 most important enzymes for TCA cycle regulation

A

highly negative Gibbs (Gibbs nga ba ung deltaGo? ahaha)

135
Q

what are the substrates for citrate synthase

A

acetylCoA and OXAA

136
Q

when [NADH/NAD] is high, the concentration of OXAA is low, therefore slowing which step of TCA cycle

A

first step

137
Q

what inhibits accumulation of isocitrate, alpha-ketoglutarate, malate oxidation in teh TCA cycle

A

high [NADH/NAD]

138
Q

examples of ‘product accumulation inhibits all 3 limiting steps of the TCA cycle’

A

inhibition of:

succinylCoA to alpha keto dehyro
citrate to itrate synthase
ATP to citrate synthase and isocitrate dehydro

139
Q

what is an activator of citrate synthase

A

ADP

140
Q

most important anaplerotic rxn in mammalian liver and kidney

A

reversible carboxylation of pyruvate by CO2 to form OXAA catalyzed by pyruvate carboxylase

141
Q

when the TCA is deficient in OXAA or any other intermediate, pyruvated is carboxylated produce __________

A

more OXAA

142
Q

what is the positive allosteric modulator of pyruvate carboxylase

A

acetylCoA

143
Q

in the absence of carbo source in ______ hrs, glycogen can provide

A

10-18

144
Q

in prolongeed fasting, ilan carbo galing kidney

A

40%

145
Q

in overnight fasting, ilan carbo galing kidney

A

10%

146
Q

substrates for gluconeogenesis

A

lactate
glucogenic AAs
glycerol

147
Q

cycle where exercising muscle cells release lactate then turned into glucose then into lctate again and then release into the blood

A

Cori cycle/lactic acid cycle

148
Q

major source of glucose during fast

A

glucogenic amino acids

149
Q

________ is a glucogenic AA converted to glucose via _______ rxn

A

alanine

trasamination

150
Q

show rxns how glycerol is a source of glucose

A

glycerol > glycerol-3-PO4 > DHAP

151
Q

what catalyzes glycerol > glycerol 3-PO4

A

glycerol kinase

152
Q

what catalyzes glycerol-3-PO4 > DHAP

A

glycerol-3-PO4 dehydrogenasw

153
Q

how many steps sa guconeogenesis

A

7

154
Q

how many glucone0genesis rxns are irreversible

A

3

155
Q

initial substrate for gluconeogensis

A

pyruvate

156
Q

1st unique step in gluconeo

A

carboxylation of pyruvate

157
Q

in gluceo neo 1st unique step, pyruvate is carboxylated to _____ by _____ then further to _______ by _____

A

OXAA
pyruvate carboxylase
PEP
PEP carboxylase

158
Q

di makapasok ang OXAA sa cytosol kaya kailanangang

A

gawing malate

159
Q

2nd unique step in gluconeo

A

decarboxylation of cytosolic oxaloacetate

160
Q

in the 2nd unique step of gluconeo, OXAA is decarboxylated and phosphorylated to ________ by _________

A

PEP

PEP-carboxykinase

161
Q

after the 2nd unique step of gluconeo, PEP follows the reverse direction of glycolysis until ____________– is formed

A

fructose-1,6-bisPO4

162
Q

3rd unique step of gluconeo

A

dephosphorylation of fructose-1,6-bisPO4

163
Q

the 3rd unique step of gluconeogenesis bypasses what

A

irreversible PFK-1

164
Q

hydrolysis of fructose-1,6-bisPO4 to ________ is catalyzwed by

A

fructose-6-phosphate

fructose 1,6-bisPO4ase

165
Q

increased level of AMP causes what to F1,6BPase and PFK1

A

inhib. F1,6BPase
activ. PFK1

therefore dec. gluconeo inc. glycolysis

166
Q

an allosteric effector of F1,6BP influenced by insulin to glucagon ratio

A

F26BP

167
Q

when is F26BP not made

A

high glucagon

168
Q

synthesis of F16BPase is induced during

A

fasting

169
Q

4th unique step of gluconeogenesis

A

dephosphorylation of glucose-6-phosphate

170
Q

in the 4th unique step of gluconeo, G6P is hydrolysed by

A

glucose-6-phosphatase

171
Q

the 4th unique step of gluconeo bypasses what

A

irreversible hexokinase/glucokinase rxn

172
Q

what are the only organs that release free glucose from glucose-6-phosphate

A

liver and kidney

173
Q

G6PO4 is transported from liver to ____

A

cytosol

174
Q

what transports G6PO4 from liver to cytosol

A

G6PO4 translocase

175
Q

recipe for gluconeogenesis

A 
2 pyru
2 CO2
6 high energy bonds
7 reversible glycolysis rxn
4 irrev. enzymes
176
Q

what are the 4 irreversible enzymes ng gluconeogenesis

A

pyruvate carboxylase
PEPCK
F16BPase
G6pase

177
Q

how many moles of pyruvate is needed to make one glucose

A

2

178
Q

how mnay moles of ATP are hydrolyzed when making glucose from pyruvate

A

2

179
Q

in gluconeogensesis, glucagon lowers which shit

A

F26BPO4

180
Q

glucagon lowering F26BPO4 results to

A

activatio of F16BPO4

inhibition of PFK1

181
Q

what does glucagon inactivate thru its cAMP-dependent protein kinase activity

A

hepatic PK

182
Q

glucagon increases the transcription of the gene for what

A

PEPCK

183
Q

acetyl CoA during fasting can divert pyruvate to ____ and away from the ____

A

gluconeo

TCA cycle

MedBiochem (16 decks)

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