E1: Regulation Of Glycogen Metabolism And Gluconeogenesis, Rushing

Front 1

two major functions of glycogen metabolism

Back 1

maintain blood glucose levels
provide a reservoir of glucose

Front 2

4 steps of glycogen degradation

Back 2

glycogen phosphorylase
transferase and debranching enzymes
phosphoglucomutase
glucose 6-phosphatase

Front 3

enzyme that takes off one glucose from glycogen, breaking an alpha 1,4 linkage

this is the first step in glycogen degradation

Back 3

glycogen phosphorylase

Front 4

enzyme that removes the last 3 glucose residues from a branch in glycogen and places them on the core branch

enzyme that removes the last glucose residue from a branch, breaking an alpha 1,6 linkage

Back 4

transferase

debranching enzyme (alpha 1,6-glucosidase)

Front 5

enzyme that converts glucose 1-phosphate to glucose 6-phosphate

Back 5

phosphoglucomutase

Front 6

rate limiting step of glycogen synthesis

Back 6

glycogen synthase step

forms the alpha 1,4 glycosidic linkages

Front 7

steps of glycogen synthesis

Back 7

G6P to G1P
G1P to UDP-glucose
UDP-glucose to glycogen via glycogen synthase

Front 8

key enzyme in glycogenolysis

Back 8

glycogen phosphorylase

Front 9

effect of phosphorylation on glycogen phosphorylase

effect of phosphorylation on glycogen synthase

Back 9

increases activity

decreases activity

Front 10

the effect that insulin has on glycogen synthesis

where in the body does this occur?

Back 10

in liver and muscle, insulin triggers dephosphorylation, which stimulates glycogen synthesis

Front 11

effect of epinephrine on glycogen levels

where does this occur in the body?

Back 11

in the liver and skeletal muscle, it triggers phosphorylation and stimulates glycogenolysis

Front 12

effect of glucagon on glycogen levels

where does this occur?

Back 12

in the liver, it triggers phosphorylation and stimulates glycogenolysis

Front 13

epinephrine and glucagon use what 2nd messenger to mediate their actions?

what enzyme does this 2nd messenger activate?

what is this enzyme's function?

Back 13

cAMP

protein kinase A

phosphoylates glycogen synthase and phosphorylase kinase (which phosphorylates glycogen phosphorylase)

Front 14

how does insulin exert it's effect on the enzymes involved in glycogen metabolism

Back 14

it activates protein phosphatase 1, which dephosphorylates glycogen synthase and glycogen phosphorylase

Front 15

location of glucose 6-phosphatase w/in the cell

what is needed for the last step of glycogenolysis to work?

Back 15

in the ER

glucose 6-phosphate transporter is needed to get G6P into the ER, where the product (glucose) is delivered into the bloodstream

Front 16

deficiency of glucose 6-phosphatase or glucose 6-phosphate transporter in the liver

what GSD is this?

clinical manifestations?

Back 16

GSD I (von Gierke)

hepatomegaly, elevated glycogen, hypoglycemia, hyperlipidemia, elevated lactate, decreased pH

Front 17

deficiency of glycogen phosphorylase in muscle

what GSD is this?

clinical manifestations?

Back 17

GSD V (McCardle)

exercise intolerance, painful muscle cramps, no build-up of lactate following exercise

Front 18

GSD that involves cardiomegaly and early death (if untreated)?

(Boards)

Back 18

GSD II (Pompe's disease)

Front 19

GSD that involves a deficiency of the debranching enzyme?

(Boards)

Back 19

GSD III (Cori)

Front 20

4 key enzymes in gluconeogenesis

which are the two most important?

Back 20

pyruvate carboxylase (2nd most important)
PEP carboxykinase
fructose 1,6-bisphosphatase (most important)
glucose 6-phosphatase

Front 21

fructose 1,6-bisphosphatase is allosterically inhibited by ___

Back 21

fructose 2,6-bisphosphate

Front 22

what enzyme is synthesized with PFK-2?

what hormone promotes its phosphorylation?

what is the effect of this phosphorylation?

Back 22

fructose 2,6-bisphosphatase

glucagon

a reduction in PFK-2 activity, increase in F-2,6-BPase activity, resulting in lower levels of F-2,6-BP

the net effect is to stimulate gluconeogenesis

Front 23

how does fatty acid oxidation affect gluconeogenesis during times of fasting?

Back 23

increased acetyl CoA allosterically activates pyruvate carboxylase and inhibits pyruvate dehydrogenase

this will promote gluconeogenesis