Chapter 16 - Key Concepts & Review Points Flashcards
_____________, the storage form of glucose, is a branched polymer.
glycogen
Glucose mobilization in the liver involves a series of conversions from ____________ to ____________ to ____________ and finally to ____________.
gylcogen
glucose-1-phosphate
glucose-6-phospate
glucose
Liver glycogen synthesis involves a series of conversions from ___________ to ____________ to ____________ and finally to ____________.
glucose
glucose-6-phosphate
UDP-glucose
glycogen
UDP-glucose is a(n) ____________.
activated molecule
Glycogen is extended from a primer built on and by the protein ____________.
glycogenin
The opposing processes of glycogen breakdown and synthesis are reciprocally regulated by ____________ and the ____________ of key enzymes.
allosteric interactions
covalent modifications
Glycogen metabolism is ultimately under the control of hormones, such as ____________, ____________, and ____________.
insulin
glucagon
epinephrine
The liver and kidney can synthesize glucose from ____________, ____________, and ____________.
lactate
pyruvate
amino acids
Glycolysis and gluconeogenesis are reciprocally regulated by ____________, ____________, and ____________.
allosteric effects
phosphorylation
changes in enzyme synthesis rates
Glycogen breakdown requires three enzymes:
____________, ____________, and ____________
glycogen phosphorylase
debranching enzyme
phosphoglucomutase
____________ coverts the glucosyl units at the nonreducing ends of glycogen to G1P.
glycogen phosphorylase
____________ transfers an alpha(1–>4)-linked trisaccharide to a nonreducing end and hydrolyzes the alpha(1–>6) linkage.
debranching enzyme
____________ converts G1P to G6P. In the liver, G6P is hydrolyzed by glucose-6-phosphatase to glucose for export to the tissues.
phosphoglucomutase
Glycogen synthesis requires a different pathway in which G1P is activated by a reaction with ____________ to form ____________.
UDP
UDP-glucose
____________ adds glucosyl units to the nonreducing ends of a growing glycogen molecule that has been primed by ____________.
glycogen synthase
glycogenin
____________ removes an alpha(1–>4)-linked 7-residue segment and reattaches it through an alpha(1–>6) linkage to form a branched chain.
branching enzyme
Glycogen metabolism is controlled in part by allosteric effectors such as ________, ________, and ________.
AMP
ATP
G6P
Covalent modification of ____________ and ____________ shifts their TR equilibria and therefore alters theirs sensitivity to allosteric effectors.
glycogen phosphorylase
glycogen synthase
Hormone signals that generate cAMP as a second messenger or that elevate intracellular Ca2+, which binds to the calmodulin subunit of phosphorylase kinase, promote ____________.
glycogen breakdown
Insulin stimulates glycogen synthesis in part by activating ____________.
phosphoprotein phosphatase-1
Compounds that can be converted to oxaloacetate can subsequently be converted to ____________.
glucose
Gluconeogensis is regulated by changes in enzyme synthesis and by allosteric effectors, including fructose-2,6-bisphosphate, which inhibits ____________ and activates ____________.
FBPas
phosphofructokinase
