Midterm 2 Flashcards

1
Q

Describe PFK2 and F26BP in the liver compared to the muscle?

A

PFK2 is phosphorylated by protein kinase a in the liver, PFK2 is inhibited and F26BP is activated. F26BP [ ] is lower and glycolysis is inhibited

PFK2 is phosphorylated by protein kinase a in the muscle, PFK2 is activated and F26Bp is inhibited. F26BP [ ] is higher and glycolysis in activated.

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2
Q

organisms maintain homeostasis by keeping concentrations of metabolites at a _________ state

A

steady

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3
Q

at steady state rate of synthesis ____ rate of breakdown of metabolites

A

equals

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4
Q

ATP inhibits the _____ step of glycolysis which is?

A

commitment step which means with abundant ATP PFK 1 is turned off

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5
Q

rates of biochemical reactions depend on?

A
  1. Temperature
  2. Concentration of reactants vs Products
  3. Concentrations of effectors
  4. Activity of the catalyst/enzyme
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6
Q

*describe how the rate of enzyme reaction depends on the concentration of substances?

A

the rate of enzyme activity is more sensitive to concentraion at low concentrations while the rate becomes insensitive at high substrate concentrations because an enzyme can only bind to one substrate

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7
Q

what is the function of PP2A?

A

dephosphorylates a number of proteins

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8
Q

phosphorylation is catalyzed by?

A

protein kinases

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9
Q

dephosphorylation is catalyzed by?

A

protein phosphatases

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10
Q

typically proteins are phosphorylated on the hydroxyl groups ____ ______ _____

A

ser thr tyr

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11
Q

increases hexokinase activity enables activation of ___________

A

glucose

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12
Q

increased PFK 1 activity enables catabolism of activated _______ via _______

A

glucose via glycolysis

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13
Q

insulin effect on ________ and ________ are major flux controllers

A

GLUT4 and hexokinase

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14
Q

*HK1 is expressed in ________

A

all tissues

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15
Q

*HKIV is expressed in the _____

A

liver

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16
Q

what are isozymes?

A

different enzymes that catalyze the same reaction

17
Q

HK4 is regulated by ?

A

sequestration and transcription

18
Q

what is favored is AMP is high, low ATP?

A

Glycolysis

19
Q

what is favored if AMP is low?

A

glucogenesis

20
Q

*what is the function of F26BP?

A
  • regulator
  • activates PFK (glycolysis)
  • inhibits F16BP (glucogenesis)
21
Q

*F26BP is produced from _______

A

F6P

22
Q

Describe regulation of PFK?

A
  • acitvated by F16BP
  • inhibited by ATP, Acetyl COA, alanine
  • in the liver inactivated by phosphorylation in response to glucose depletion
23
Q

what are the two alternative fates for pyruvate?

A
  • store energy as glycogen, generate NADPH via pentose phosphate pathway
  • source of acetyl coA, store energy as body fat, make ATP via citric acid cycle
24
Q

ChREBP activates transcription in response to __________

A

glucose

25
Q

FOXO1 activates transcription in response to __________

A

insulin

26
Q

glucose residues are removed from glycogen by _______ ______

A

glycogen phosphorylase

27
Q

glucose - P must eb isomerized to glucose 6 P to be metabolized, this is done by _____________

A

phosphoglucomutase

28
Q

glucose 6P is dephosphoylated in the _______ for transport into the bloodstream, this is preformed by ______________

A

liver, glucose 6 phosphatase (gluconeogenic enzyme)

29
Q

glycogen synthesis occurs in the _____ and _______

A

liver and msucle

30
Q

what are the 4 enzyme reactions involved in glycogen synthesis?

A
  1. UDP glucose pyrophosphorylase
  2. Glycogen synthase
  3. Glycogen branching enzyme
  4. Glycogenin
31
Q

glycogen storage disease is ?

A

genetic enzyme deficiencies associated with excessive glycogen accumulation within cells

32
Q

liver phosphorylase b is not activated by _____

A

AMP

33
Q

liver phosphorylase a is deactivated by _________

A

glucose

34
Q

do muscle cells contain glucose 6 phosphatase?

A

no

35
Q

insulin does what 3 main things?

A
  • increases glucose import into the muscle
  • stimulates activity of muscle hexokinase
  • activates glycogen synthase