16 Flashcards

1
Q

review the steps of glycolysis

A

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2
Q

review gibbs free energy

A

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3
Q

what three reactions have large change in free energy? in glycolysis

A

glucose + atp -> glucose + adp
fructose + atp -> fructose + adp
phosphoenolpyruvate + adp -> pyruvate + atp

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4
Q

three big reactions of glycolysis are _____ and their enzymes are _____

A

irreversible
regulated

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5
Q

change in free energy for all other steps of glycolysis other than the three major ones are close to ____ and these reactions are largely _____

A

zero
reversible

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6
Q

glycolytic pathway resembles a series of _____ connected by __

A

resevoirs (metabolic pool)
dams

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7
Q

the irreversible ‘dams’ are irreversible ________ and are _______ of the pathway which _______ glycolysis

A

reactions
points of regulation
control

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8
Q

______ is the main regulatory enzyme in glycolysis

A

phosphofructokinase (1 and 2)

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9
Q

allosteric regulation

A

common mechanism
upstream or downstream metabolites from same or different pathway
general metabolic indicators
allosteric - another side

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10
Q

hexokinase is inhibited by ___

A

its own product

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11
Q

product inhibition is a form of ____

A

feedback inhibition

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12
Q

phosphofructokinase 1 and 2 is an ____

A

allosteric enzyme - regulated by allosteric effectors

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13
Q

when citrate accumulates, there is no need to produce further ____

A

ATP

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14
Q

ATP build up indicates no need for more ____ - therefore there is PFK-1 ____-

A

energy
inhibition

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15
Q

sufficient ATP levels mean glycolysis is ____

A

deactivated

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16
Q

sufficient ATP levels mean glycolysis is ____

A

deactivated

17
Q

Low ATP/AMP ratio indicates energy is ______ - therefore PFK-1 _______

A

needed
activation

18
Q

when ATP is needed, glycolysis is _____

A

stimulated

19
Q

high levels of citrate are _____ of PFK-1: biosyntehtic precursors are ____ and therefore further consumption of ___ is not needed

A

inhibitory
abundant
glucose

20
Q

______ is the most important activator for PFK-1 in eukaryotes, controls glycolysis in liver

A

fructose-2,6-bisphosphate

21
Q

High H+ concentration also ____ PFK-1: pH falls when muscles work ____, and therefore glycolysis ______ prevents accumulation of lactic acid

A

Inhibits
Anaerobicaly
Inhibition

22
Q

When pyruvate and ATP get produced, which acts as an inhibitor?

A

ATP

23
Q

Can enzymes change their activity if they are phosphorylated or not?

A

yes

24
Q

Which is form of pyruvate kinase is more active? Phosphorylated, or dephosphorylated?

A

Dephosphorylated

25
Q

Under aerobic conditions, what happens to pyruvate?

A

Oxidized to acetyl CoA - citric acid cycle, electron transport chain

26
Q

Under anaerobic conditions, what happens to pyruvate? (2)

A

Converted to ethanol (microorganisms, fermentation)
Converted to lactate (muscles, RBC)

27
Q

Pyruvate decarboxylation involves what important reaction?

A

Pyruvate dehydrogenase

28
Q

The pyruvate dehydrogenase complex is a large molecule with ____ enzymes

A

Three

29
Q

How many copies of E1, E2, and E3 are there in pyruvate decarboxylation?

A

24, 24, 12 respectively (60 total subunits)

30
Q

In eukaryotes, pyruvate dehydrogenase complex is located in the _____

A

Mitochondrial matrix

31
Q

In eukaryotes, pyruvate translocase is located in the ____

A

Inner mitochondrial membrane

32
Q

Molecules that transport in the same direction are called

A

Symporter