Chapter 9 Citric Acid Cycle (slide notes) Flashcards
for sugars with more than one chiral center, the D or L designiation refers to ___________
the assymetric carbon farthest from the aldehyde or keto group
D and L sugars are ________ of one another
mirror images
when is it an alpha anomer and when is it a beta anomer?
it is alpha when it is same side as OH . it is beta when it is the opposite. Note OH can b L (on left) or D (on right)
glycogen synthase is usually inactive when in the ______ form, and is usually active when in the __________ form
unactive phosphorylated b form
active in unphosphorlayted a form
insulin stimulates glycogen synthesis by ____________
inactivating glycogen sythase kinase
glycogen degradation in the livers is inhibited and glycogen sythesis is stimulated by high blood-glucose levels. The infusion of glucose into the blood stream leads to the inactivation of ________ followed by the activation of glycogen synthase in the liver
inactivation of phosphorylase1`
cellular respiration is the source of how much ATP??
90%
pyruvate is generated in the __________while the citric acid cycle occurs in the ___________
cytosol
mitochondria
define reduction potential
it is the tendency for a specific substance to gain electrons
Redox coenzyme:nicotinic acid:
universal electron carrier- NAD and NADP
dehydrogenases
Redox coenzyme:riboflavin (vitamen b2)
component of
-FMN and FAD
flavoproteins dyhydrogenase, oxidases, hydroxylases
it is a donor or acceptor of 2 H atoms
Coenzyme A is an __________
acyl carrier molecule
acetyl is derived from catabolism of _______,_______ and ________
carbohydrates, lipids, amino acids
pyruvate dehydrogenase complex, a mitochondrial matrix enzyme, oxidateively carboxylates pyruvate to form acetyl coA.
this reaction is _______ link between glycolysis and the citric acid cycle
irreversible
step 1 of decarboxylation:
________ a component of the complex, catalyzes the decarboxylation. Pyruvate combines with ionized form of the coenzyme thiamine pyrophosphate
step 2-oxidation
‘
the _________ is oxidized and transferred to dihydrolipoamide to form acetyllipoamide on E2 in a reaction also catalyzed by E1
step 3-formation of acetyl CoA
E2 catalyzes the transfer of the acetyl group from acetylipoamide to coenzyme A from acetly Coa
pyruvate dehydrogenase
two carbon fragment
dihydrolipoamide is formed by the attachment of the vitamen lipoic acid to a lysine residue in another enzyme in the complex ______________-
dihydrolipoyl transacetylase
to participate in another reaction in the cycle, dihydrolipoamide must be ______. this reaction is catalyzed by __________–
reoxidized
dihydrolipoamide dehydrogenase
the three enzymes of the pyruvate dehydrogenase complex are structurally integrated, and the __________ arm allows rapid movement of substartes and products from one active site of the complex to another
lipoamide arm
the formation of acetyl CoA from pyruvate is _____ in animal cells
irreversible
______________- catalyzes the condensation of acetyl CoA and oxaloacetate to form citrate
citrate synthase
oxaloacetate binding by ________ induces structural changes that lead to the formation of the acetyl coA binding site
citrate synthase
the formation of the reaction intermediate citry CoA causes a structural change that complese active site formation
citryl coA is cleaved to form citrate and coenzyme A
_____________- catalyzes the formation of isocitrate from citratte
acontitase
______________ catalyzes the oxidative decarboxylation of isocitrate, forming alpha-ketoglutarate and capturing high energy electrons as NADH
isocitrate dehydrogenase
alpha-ketoglutarate dehydrogenase complex =
catalyzes the synthesis of succinyl coA from alpha ketoglutarate, generating NADH
the enzyme and the reactions are structurally and mechanistically similar to the pyruvate dehydrogenase complex (E1-E3)
