E1: Regulation Of Glycolysis & Citric Acid Cycle, Rushing

Front 1

enzyme that phosphorylates glucose in most tissues

what is the resulting compound?

Back 1

hexokinase

G6P

Front 2

in what organs does glucokinase substitute for hexokinase?

what is the difference between them?

Back 2

liver, beta cells of pancreas, intestines

glucokinase has a lower affinity for glucose, so these cells only use glucose when it is in high concentrations in the body

Front 3

what is the most important regulatory enzyme in glycolysis

why?

Back 3

phosphofructokinase (PFK-1)

it catalyzes the committed step in glycolysis

Front 4

what do kinases do?

what do phosphatases do?

Back 4

phosphorylate

de-phosphorylate

Front 5

enzyme that catalyzes the final step in glycolysis

what is produced?

Back 5

pyruvate kinase

pyruvate

Front 6

what is the last step of glycolysis

Back 6

phosphoenolpyruvate (PEP) to pyruvate via pyruvate kinase

Front 7

what step of glycolysis produces 4 ATPs per molecule of glucose?

Back 7

PEP to pyruvate (the last step)

Front 8

what enzymes catalyze the steps of glycolysis that use up 1 ATP each?

Back 8

hexokinase/glucokinase and PFK-1

Front 9

hexokinase is inhibited by ____

glucokinase is inhibited by ____

Back 9

G6P

F6P

Front 10

allosteric inhibitor of PFK-1

Back 10

ATP (with the help of citrate)

Front 11

potent activator of PFK-1

how is this activator formed

Back 11

fructose 2,6-bisphosphate

it is formed from F6P via PFK-2

Front 12

effect of glucagon on glycolysis

when does this occur?

Back 12

via cAMP-dependent protein kinase, triggers phosphorylation of PKF-2, which reduces the enzyme's activity

this occurs when blood glucose is low

Front 13

the common pathway for the metabolism of all fuels

Back 13

citric acid cycle

Front 14

purposes of the citric acid cycle

Back 14

to produce substrates for the electron transport chain as well as precursors for various biosynthetic pathways

Front 15

4 key enzymes in the regulation of the citric acid cycle

Back 15

pyruvate dehydrogenase
citrate synthase
isocitrate dehydrogenase
alpha-ketoglutarate dehydrogenase

Front 16

the activity of the citric acid cycle depends on the availability of ___ for several of the dehydrogenases

Back 16

NAD+

Front 17

the amount of NAD+ available for the citric acid cycle is related to ____

Back 17

the rate of NADH consumption in the process of oxidative phosphorylation

Front 18

what enzyme is responsible for creating acetyl CoA

Back 18

pyruvate dehydrogenase

Front 19

what 4 groups of molecules allosterically inhibit PDH

what other enzyme do they activate, and what is it's function?

Back 19

NADH, acetyl CoA, ATP, and fatty acids

they stimulate PDH kinase, which phosphorylates PDH, reducing its activity

Front 20

electrolyte that activates PDH phosphatase in muscle

what is it's effect?

Back 20

Ca++

restores the activity of PDH, stimulating the citric acid cycle

Front 21

molecules that that activate PDH phosphatase (4)

Back 21

Ca2+, AMP, CoA, and NAD+

Front 22

effect that insulin has on the citric acid cycle

Back 22

stimulates PDH via activation of PDH phosphatase (when glucose is abundant)

Front 23

citrate synthase activity is limited by the availability of ___ and ___

Back 23

oxaloacetate and acetyl CoA

Front 24

two enzymes of the citric acid cycle that are inhibited by NADH

in muscle, however, ___ activates these enzymes

Back 24

isocitrate dehydrogenase and alpha-ketoglutarate dehydrogenase

Ca++

Front 25

two enzymes of the citric acid cycle that are inhibited by ATP

Back 25

citrate synthase and isocitrate dehydrogenase

Front 26

what form of pyruvate kinase is the active one?

when is this form more prominent?

Back 26

dephosphorylated pyruvate kinase

more prominent w/ high blood glucose level