Biochem Test 3 Glucogeneisis Slideshow

what is glucogenesis

the process of building glucose from metabolites such as pyruvate

is glucogenesis catabolic or ananbolic

anabolic

what two molecules can be recycled back into useable glucose

pyruvate and lactate

where does glucogensis occur

in the liver and kidneys

is glucogeneis a favorable rxn

glucogenesis must use energy coupled rxns to make it favorable

what happens to glycolysis when glucogenisis is active

glycolysis is off

what happens to glucogenesis when glycolysis is active

glycogenesis is off

what can be turned into glucose (3)

• most aas

• glycerol

• citric acid cycle intermidiates

what can’t be made into glucose

fatty acids

what two molecules are consumed to make glucose

ATP and NADH

is glycolysis exergonic or endergonic

exergonic

which rxns are shared between glucogenesis and glycolysis and are these reactions reversible or irreversible

• rxns 2 and 4-9

• reversible

what rxns are not shared between glucogenesis and glycolysis and are these rxns endergonic or eexergonic, and are they reversible or irreversible

• rxn 1 → hexokinase

• rxn,3 → phosphofructose kinase

• rxn 10 → pyruvate kinase

• high exergonic

• irreversible

what enzymes are replaced in glucogensis for rxn 1

glucose-6-phosphate replaces hexokinase

what does glucose-6-phosphate do

converts glucose-6-phosphate to glucose via dephosphorylation

what what enzymes are replaced in glucogensis for rxn 3

fructose-1,6,-bisphosphate replaces phosphofructose kinase

what does fructose-1,6,-bisphosphate do

fructose-1,6,-bisphosphate converts fructose-1,6-bisphosphate to fructose-6-phosphate via dephosphorylation

what enzymes are replaced in glucogensis for rxn 10

pyruvate carboxylase and pep carboxylase replace pyruvate kinase

what does pyruvate carboxylase do

converts oxaloacetate to PEP

what does PEP carboxykinase do

converts oxaloacetate to PEP

what molecules can be used in glucogenesis to make glucose (5)

• pyruvae

• lactate

• glycerol

• aa

• TCA cycle intermidiates

what molecules can’t be used in glucogenesis to make glucose and why

fatty acids because breaking down fatty acids produces acetyl CoA and theres no net synthesis of glucose

what coenzyme does pyruvate carboxylase require

biotin

what is the allosteric activator of pyruvate carboxylase?

Acetyl CoA

under what conditions is pyruvate carboxylase active

when ATP and Acetyl CoA are high

what happens when pyruvate carboxylase is active?

glucogenesis is turned on

pyruvate kinase activation pathway

high ATP or Acetyl CoA → pyruvate carboxylase active → glucogenesis is turned on

pyruvate kinase inhibition pathway

low ATP or Acetyl CoA → pyruvate carboxylase inactive → pyruvate goes to the TCA cycle

where is pyruvate carboxylase located

inside the mitochondrial matrix

how does oxaloacetate leave the matrix?

oxaloactate is temporarily converted to malate dehydrogenase → malate exits the matrix & enters the cytoplasm via malate transport protein → malate is oxidized back to oxaloactate i

why is pyruvate carboxylase compartmentalized

prevents glycolysis and glucogenesis from occurring at the same time

what two factors make the PEP carboxylase rxn favorable?

decarboxylation and GTP hydrolysis

what does fructose 1-6 bisphosphate do

removes a phosphate group from fructose-1-6-bisphosphate using H2O to convert it to fructose-6-phosphate

what activates fructose-1,6-bisphosphate

citrate

what happens when fructose-1,6-bisphosphate is activated

glycolysis is turned off, PFK is inhibited

what inhibits fructose-1,6-bisphosphate

high AMP and fructose-2,6-bisphosphate

what happens when fructose-1,6-bisphosphate is inhibited

PFK and glycolysis is turned on

is PFK part of glycolsis or glucogenesis

glycolsis

is fructose-1,6,-bisphosphate a part of glycolsis or glucogenesis

glucogenesis

high glucose pathway

high glucose → insulin released → dephosphorylated → PFK02 active → high fructose-2,6-bisphosphate → glycolysis on

low glucose pathway

low glucose → glycagon released → phosphorylated → fructose bisphosphotase-2 active → low fructose-2,6-bisphosphate → glucogenesis on