bich 2 exam 2 Flashcards
draw the steps of gluceogenesis
glucose 6P –> glucose by glucose-6-phosphatase
fructose 1,6 bisphosphate –> fructose 6-phophate by fructose 1,6-bisphosphatase
pyruvate –> oxaloacetate –> phosphoenolpyruvate by pyruvate carboxylase and PEP carboxykinase
draw glycogen synthesis
answer on doc
draw glycogen catabolism
answer on doc
draw TCA cycle
answer on doc
draw oxaloacetate
answer on doc
draw citrate
answer on doc
draw isocitrate
answer on doc
draw alpha-ketoglutarate
answer on doc
draw succinyl-coA
answer on doc
draw succinate
answer on doc
draw fumarate
answer on doc
draw malate
answer on doc
draw pyruvate dehydrogenase reaction
answer on doc under TCA
What is the purpose of the glyoxylate cycle?
It short cuts the TCA cycle so no carbon is lost as CO2.
ANABOLIC AND CATABOLIC. Produces NADH and FADH2 to power electron transport
intermediate for biosynthesis
Glyoxylate pathway in plants:
occurs in glyoxysome
seeds oxidize fatty acids to acetylCoA and its used to glyoxylate pathways to support growth
glyoxylate shunt cannot use photosynthesis yet
draw the glyoxylate pathway
isocitrate –> glyoxylate + succinate… glyoxylate –> malate (proceeds through TCA)
what molecules can go in and out of the mitochondria?
pyruvate, citrate, malate
what cannot go in and out of the mitochondria?
Acetyl CoA and oxaloacetate
What are anaplerotic reactions?
reactions that fill up or replenish TCA intermediates
TCA cycle is regulated by what?
NAD+/NADH, Acetyl CoA, ADP/ATP
Committed step of TCA cycle:
pyruvate dehydrogenase
Pyruvate dehydrogenase regulators
increase: NAD+, CoA
decrease: acetyl-CoA, NADH, ATP
hexokinase I regulation
in brain tissue
inhibited by glucose 6P
expressed in most tissues other than liver dimer
glucokinase regulation and purpose
induced by insulin.. need a high level of glucose for it to be active
soaks of excess glucose into liver for other pathways
glucokinase vs glucose6-phophatase
Glucose 6-P works in the opposite direction of glucokinase.
Not inhibited by G6P
how are enzymes of glycolysis and gluconeogenesis would be regulated under a given
set of conditions in a cell?
what are the key regulated enzymes that partition glucose6-P between all the pathways?
Glycogen phosphorylase
Glycogen Sythase
Glucose 6P phosphatase
phosphofructokinase
Glucose 6P dehydrogenase
Allosteric regulation of glycogen synthase
Allosteric activater: G6P
inhibitor: cAMP depending phosphorylation
Allosteric regulation of glycogen phosphorylase
Allosterically Activated by AMP
Allosterically Inhibited By ATP, G6P
Draw Hormonal regulation for glucagon of glycogen synthase and glycogen phosphorylase via
phosphorylation
see doc
Be able to describe why and how concentrations of NAD+/NAD, acetyl-CoA/CoA, and ADP/ATP
regulate the TCA cycle, based on the energy or biosynthetic needs of a cell.
isocitrate dehydrogenase regulation and why
Activators: ADP
Inhibitors: NADH, ATP
When activated citrate goes through TCA cycle when low ADP and high ATP goes to cytosol
Step before isocitrate converts to alpha-ketoglutarate in the mitochondria and cannot be converted back. Before that it can be converted back to citrate and moved into the cytosol to make fatty acids, and steroids.
E equation for half reactions
E = Eo + (RT/nF) ln(ox/red)
How is E related to G
G= -nFE
What does E stand for
standard reduction potential… tendency of chemical species to be reduced
What direction will a reaction go if E is negative?
If G is negative, E is positive so spontaneous is positive E
Recognized FAD, TPP, CoA, Lipoic Acid, Biotin
on doc
How is FAD used?
It is used for regulation and can pick up two protons
Phosphofructosekinase in glycolysis is regulated by:
inhibited by ATP, citrate
activated by AMP, fructose 2,6-bisphospahte
Fructose1,6-bisphosphate phosphatase regulation gluconeogenesis
Activated by citrate
Inhibited by AMP, fructose 2,6bP
pyruvate kinase regulation
Inhibited by ATP and alanine
makes PEP available for gluconeogenesis
Where all is G6P used?
glycogen, gluconeogenesis, glycolysis, pentose phosphate
Glucose 6-P dehydrogenase (pentose phosphate shunt) regulation
inhibited by NADPH, fatty acyl-CoA
Purposes of Pentose Phosphate Shunte
Generates NADPH for biosynthesis
In cytosol
Generate ribose 5-P which builds nucleic acids
Products feed into glycolysis/ gluconeogenesis to convert glucose into pyruvate
What reactions are anaplerotic?
Pyruvate carboxylase and Malic Enzyme
Pyruvate carboxylase regulation
activated by acetyl CoA
alpha ketoglutarate dehydrogenase regulation
Activated by AMP
Inhibited by NADH and succinyl CoA
Draw succinyl CoA synthase reaction
on doc
draw pyruvate carboxylase
in spiral notebook
Draw Hormonal regulation for insulin of glycogen synthase and glycogen phosphorylase via
phosphorylation
on doc
Look at transketolase reaction
on paper
Look at transaldolase reaction
on paper