Chapter 16 - Key Concepts & Review Points

Question 1

_____________, the storage form of glucose, is a branched polymer.

Answer 1

glycogen

Question 2

Glucose mobilization in the liver involves a series of conversions from ____________ to ____________ to ____________ and finally to ____________.

Answer 2

gylcogen
glucose-1-phosphate
glucose-6-phospate
glucose

Question 3

Liver glycogen synthesis involves a series of conversions from ___________ to ____________ to ____________ and finally to ____________.

Answer 3

glucose
glucose-6-phosphate
UDP-glucose
glycogen

Question 4

UDP-glucose is a(n) ____________.

Answer 4

activated molecule

Question 5

Glycogen is extended from a primer built on and by the protein ____________.

Answer 5

glycogenin

Question 6

The opposing processes of glycogen breakdown and synthesis are reciprocally regulated by ____________ and the ____________ of key enzymes.

Answer 6

allosteric interactions

covalent modifications

Question 7

Glycogen metabolism is ultimately under the control of hormones, such as ____________, ____________, and ____________.

Answer 7

insulin
glucagon
epinephrine

Question 8

The liver and kidney can synthesize glucose from ____________, ____________, and ____________.

Answer 8

lactate
pyruvate
amino acids

Question 9

Glycolysis and gluconeogenesis are reciprocally regulated by ____________, ____________, and ____________.

Answer 9

allosteric effects
phosphorylation
changes in enzyme synthesis rates

Question 10

Glycogen breakdown requires three enzymes:

____________, ____________, and ____________

Answer 10

glycogen phosphorylase
debranching enzyme
phosphoglucomutase

Question 11

____________ coverts the glucosyl units at the nonreducing ends of glycogen to G1P.

Answer 11

glycogen phosphorylase

Question 12

____________ transfers an alpha(1–>4)-linked trisaccharide to a nonreducing end and hydrolyzes the alpha(1–>6) linkage.

Answer 12

debranching enzyme

Question 13

____________ converts G1P to G6P. In the liver, G6P is hydrolyzed by glucose-6-phosphatase to glucose for export to the tissues.

Answer 13

phosphoglucomutase

Question 14

Glycogen synthesis requires a different pathway in which G1P is activated by a reaction with ____________ to form ____________.

Answer 14

UDP

UDP-glucose

Question 15

____________ adds glucosyl units to the nonreducing ends of a growing glycogen molecule that has been primed by ____________.

Answer 15

glycogen synthase

glycogenin

Question 16

____________ removes an alpha(1–>4)-linked 7-residue segment and reattaches it through an alpha(1–>6) linkage to form a branched chain.

Answer 16

branching enzyme

Question 17

Glycogen metabolism is controlled in part by allosteric effectors such as ________, ________, and ________.

Answer 17

AMP
ATP
G6P

Question 18

Covalent modification of ____________ and ____________ shifts their TR equilibria and therefore alters theirs sensitivity to allosteric effectors.

Answer 18

glycogen phosphorylase

glycogen synthase

Question 19

Hormone signals that generate cAMP as a second messenger or that elevate intracellular Ca2+, which binds to the calmodulin subunit of phosphorylase kinase, promote ____________.

Answer 19

glycogen breakdown

Question 20

Insulin stimulates glycogen synthesis in part by activating ____________.

Answer 20

phosphoprotein phosphatase-1

Question 21

Compounds that can be converted to oxaloacetate can subsequently be converted to ____________.

Answer 21

glucose

Question 22

Gluconeogensis is regulated by changes in enzyme synthesis and by allosteric effectors, including fructose-2,6-bisphosphate, which inhibits ____________ and activates ____________.

Answer 22

FBPas

phosphofructokinase