Glycolysis and TCA Flashcards
Hexokinase is a key glycolytic enzyme.
T/F
T
Hexokinase catalyses a regulatory step in glycolysis that is (reversible or irreversible?) .
Irreversible
the irreversibility catalyzed by hexokinase in glycolysis is circumvented by another enzyme ___________ .
glucose-6-phosphatase
Hexokinase and _____ may be considered as iso-enzymes
glucokinase
Which is under the influence of insulin and which isn’t
Glucokinase or hexokinase
Glucokinase is under the influence of insulin; but hexokinase is not.
The _____ of glucose traps it within the cells
phosphorylation
PFK is an ____, _____, and ____ enzyme.
allosteric
inducible
regulatory
the rate limiting reaction in glycolysis is catalyzed by ______ enzyme and is the conversion of _____ to ______
However, during gluconeogenesis, this step is circumvented by _________.
Phosphofructokinase
From fructose-6 phosphate to fructose 1,6 biphosphate
fructose-1,6-bisphosphatase
Which steps of glycolysis are referred to as the preparatory phase
The steps 1,2 and 3 together are called as the preparatory phase.
1,3-bisphospho glycerate contains a (high or low?) energy bond.
High
Enolase requires ____ ions and will (reversibly or irreversibly?) be inhibited by ______ .
Mg++
Irreversibly
fluoride
fluoride will stop the whole glycolysis
T/F
T
In anaerobic condition, pyruvate is reduced to _____ by ______
lactate by lactate dehydrogenase
In RBCs
there are no _____. Hence RBCs derive energy only through _____, where the end product is _____\
mitochondria
glycolysis
lactic acid.
GLYCOLYSIS
Aka
_________ pathway
embden-meyerhof-parnas
glucose to ______ ( aerobic )
-glucose to _____ (anaerobic)
Pyruvate
lactate
all reactions in glycolysis take place in the _____
cytoplasm
FUN PART
(1) Glucose to ______
- _______(______ in liver)
(2) _______ to ______
- ___________
(3) _________ to ______
- _________
(4) ___________ to _________
- aldolase
- reversible
(5) G3P to 1,3 biphosphoglycerate
- _______________
(6) _________ to _______
- ______________
(7) ________ to ______
- _________
(8) _________ to _______
- ______
(9) _______ to ______
- _______
Glucose 6 phosphate; hexokinase; glucokinase
Glucose 6 phosphate to fructose 6 phosphate ; phosphohexose isomerase
Fructose 6 phosphate to Fructose 1,6 bi phosphate ; phosphofructo kinase
Fructose 1,6 bi phosphate to 2 mol of glyceraldehyde 3 phosphate or dihydroxyacetone phosphate; G3P dehydrogenase
1,3 biphosphoglycerate to 3 phosphoglycerate; 1,3 bi phosphoglycerate kinase
3 phosphoglycate to 2 phosphoglycerate; phosphoglycero mutase
2 phosphoglycerate to phosphonenolpyruvate ; enolase
phosphoenolpyruvate to Pyruvate; Pyruvate kinase
ATP is used In Which steps in glycolysis and say the conversions
1 and 3
Glucose to Glucose 6 phosphate
Fructose 6 phosphate to Fructose 1,6 bi phosphate
Which step of glycolysis is NADH produced
G3P to 1,3 biphosphoglycerate
Regulatory enzymes of glycolysis
List the 4
Hexokinase
Phosphofructokinase
Pyruvate kinase
Pyruvate dehydrogenase
ATP is produced In Which steps in glycolysis and say the conversions
1,3 biphosphoglycerate to 3 phosphoglycerate
And
phosphoenolpyruvate to Pyruvate
Irreversible steps of glycolysis
1= glucose to glucose 6 phosphate
3= fructose 6 phosphate to fructose 1,6 biphosphate
9= phosphoenolpyruvate to Pyruvate
Glucokinase can act when there is shortage of glucose.
T/F
With reason
F
Glucokinase can act only when there is plentyof glucose.
It has low affinity and high Km for glucose
Phosphofructokinase
__________ are the mostimportant allosteric inhibitors.
____ acts as an allosteric activator
ATP and citrate
AMP
When energy is plenty in the cell, glycolysis is (inhibited or activated?)
inhibited
___________ acts as a link between catabolic and anabolic pathways (amphibolic role).
TCA cycle
Pyruvate derived from glycolysis is __________ to acetyl CoA by ________
oxidatively decarboxylated
pyruvate dehydrogenase
The pyruvate dehydrogenase reaction occurs in the _________.
mitochondria
Pyruvate can enter the mitochondria from the cytoplasm by itself
T/F
F
Pyruvate with the help of a carrier can enter the mitochondria from the cytoplasm.
All the enzymes of citric acid cycle are located inside the _____________.
mitochondria
TCA cycle
From acetyl coA + ________
To ________
To ________
To _________
To __________
To _________
To _________
To __________
To ___________
Oxaloacetate
Citrate
Isocitrate
Alpha keto glutarate
Succinyl coA
Succinate
Fumarate
Malate
Oxaloacetate
Formation of Citric Acid
The __ carbon, _____ condenses with __ carbon, ____ to form __ carbon compound, the _____
The enzyme is ______.
This is (a reversible or an irreversible?) step.
However, body can reverse this step by another enzyme, _______________
4; oxaloacetate
2; acetyl CoA
6; citrate
citrate synthase
an irreversible
ATP-citrate lyase
Formation of Isocitrate
Citrate is isomerized to isocitrate by _______ .
This reaction is a two-step process. At first, _______ is removed from citrate forming ________ .
Immediately, _________ is added to _____ to form isocitrate. Thus the position of the hydroxyl group is shifted.
aconitase
one water molecule; cis aconitate
one water molecule ; aconitate
cis aconitate
a ______ compound with a very (short or long?) half-life
transient
Short
Formation of Alpha Ketoglutarate
This reaction is a two-step process, both catalyzed by the same enzyme, ___________
In the first part of the reaction, isocitrate is _________ to form _____.
It is an unstable compound which undergoes spontaneous ______ to form alpha ketoglutarate.
isocitrate dehydrogenase
dehyrogenated; oxalosuccinate
decarboxylation
The ______ generated in formation of alpha ketoglutarte step is later oxidized in electron transport chain (ETC) to generate ATPs
NADH
Isocitrate (__ carbons) undergoes oxidative decarboxylation to form alpha ketoglutarate (__ carbons).
In this reaction, one molecule of ___ is liberated.
6; 5
CO2
Formation of Succinyl CoA
alpha ketoglutarate is oxidatively decarboxylated to form succinyl CoA by the enzyme ___________
alpha ketoglutarate dehydrogenase
Formation of succinyl coA
The ____ thus generated enters into ETC to generate ATPs.
One molecule of ___ is removed in this step.
NADH
CO2
the irreversible step in the whole TCA reaction cycle is ?
Formation of succinyl coA
Generation of Succinate
The enzyme is _______ .
A molecule of ___ is phosphorylated to ___ which can be converted to _____ by reacting with an _____ molecule
succinate thiokinase
GDP; GTP
ATP
ADP
Formation of Fumarate
Succinate is dehydrogenated to fumarate by ____________
The hydrogen atoms are accepted by _____ to become _____ then enters into ETC to generate ATPs.
succinate dehydrogenase
FAD
FADH2
fumarate
(Saturated or unsaturated?)
(Mono or di?) carboxylic acid
Unsaturated
Di
succinate dehydrogenase
The enzyme is a ___protein.
flavo
The succinate dehydrogenase is competitively inhibited by ______
malonate
Formation of Malate
The formation of malate from fumarate is catalyzed by _______.
The reaction involves the addition of a _____ molecule.
fumarase
water
In formation of malate
L and D- malate is formed.
F
Only L-malate is formed.
Regeneration of Oxaloacetate
Finally malate is oxidized to oxaloacetate by ________ .
The ____ is generated in this step, which enters the electron transport chain, when ATPs are produced.
malate dehydrogenase
NADH
____________ reaction is the only one irreversible step in the cycle
Alpha ketoglutarate dehydrogenase
