bch exam 1 hw
removes terminal glucose residues from glycogen by cleaving alpha-1,4 - correct answer ✔✔glycogen
phosphorylase
enzyme activity stops when the enzyme reaches a point ___ glucose residues from a branch point, which
is a ___ linkage - correct answer ✔✔four, alpha-1,6
enzyme ___ continues removing terminal glucose residues - correct answer ✔✔glycogen phosphorylase
transferase - correct answer ✔✔alpha-1,4
glucosidase - correct answer ✔✔alpha-16
Predict the effect of the mutation on glycogen metabolism - correct answer ✔✔glycogen molecules with
branches containing a single glucose residue
order of events of the signal-transduction for glycogen degradation in muscle - correct answer
✔✔Muscle contraction begins.
Phosphorylase kinase is partly activated by binding Ca2+.
The stimulatory Galpha protein dissociates and activates adenylate cyclase.
Intracellular cAMP levels increase, activates protein kinase A.
Phosphorylase kinase is phosphorylated on its beta and alpha subunits.
Glycogen phosphorylase b is converted to glycogen phosphorylase a.
Phosphorolysis of glycogen yields glucose 1-phosphate.
Which of the following mutations in muscle glycogen phosphorylase could result in a condition similar to
McArdle disease? - correct answer ✔✔Mutant muscle glycogen phosphorylase is unable to bind to AMP.
, glucagon - correct answer ✔✔-secreted by pancreatic alpha cells
-polypeptide
epinephrine - correct answer ✔✔-derived from tyrosine
-stimulates muscle cells to break down glycogen
-released in response to stress
both - correct answer ✔✔-released in response to a drop in blood glucose levels
-inhibits glycolysis and stimulates gluconeogenesis in the liver
-the receptor has 7 transmembrane alpha helices
Water is prevented from entering the active site of glycogen phosphorylase. What are the advantages of
excluding water from the active site? - correct answer ✔✔-to maintain energy supplies in muscle cells
-to prevent the formation of glucose
-to prevent energy waste by conserving the ATP that would be needed to phosphorylate glucose
In the liver, stimulation of the glucagon receptor leads to - correct answer ✔✔-activation of PKA
-activation of glycogen phosphorylase
-conversion of ATP to cAMP
-activation of fructose 1,6-biphosphatase
Regardless of its efficacy, what is the reasoning behind carbohydrate loading? - correct answer
✔✔Glucose is stored as glycogen, which can be broken down to supply energy during the event.
Select all of the carbohydrate pathways that glucagon stimulates in the liver. - correct answer
✔✔gluconeogenesis and glycogen breakdown
Glycogen phosphorylase in muscle - correct answer ✔✔-activation generates glucose for the cell
-b form is the default state
-AMP binding induces R state
removes terminal glucose residues from glycogen by cleaving alpha-1,4 - correct answer ✔✔glycogen
phosphorylase
enzyme activity stops when the enzyme reaches a point ___ glucose residues from a branch point, which
is a ___ linkage - correct answer ✔✔four, alpha-1,6
enzyme ___ continues removing terminal glucose residues - correct answer ✔✔glycogen phosphorylase
transferase - correct answer ✔✔alpha-1,4
glucosidase - correct answer ✔✔alpha-16
Predict the effect of the mutation on glycogen metabolism - correct answer ✔✔glycogen molecules with
branches containing a single glucose residue
order of events of the signal-transduction for glycogen degradation in muscle - correct answer
✔✔Muscle contraction begins.
Phosphorylase kinase is partly activated by binding Ca2+.
The stimulatory Galpha protein dissociates and activates adenylate cyclase.
Intracellular cAMP levels increase, activates protein kinase A.
Phosphorylase kinase is phosphorylated on its beta and alpha subunits.
Glycogen phosphorylase b is converted to glycogen phosphorylase a.
Phosphorolysis of glycogen yields glucose 1-phosphate.
Which of the following mutations in muscle glycogen phosphorylase could result in a condition similar to
McArdle disease? - correct answer ✔✔Mutant muscle glycogen phosphorylase is unable to bind to AMP.
, glucagon - correct answer ✔✔-secreted by pancreatic alpha cells
-polypeptide
epinephrine - correct answer ✔✔-derived from tyrosine
-stimulates muscle cells to break down glycogen
-released in response to stress
both - correct answer ✔✔-released in response to a drop in blood glucose levels
-inhibits glycolysis and stimulates gluconeogenesis in the liver
-the receptor has 7 transmembrane alpha helices
Water is prevented from entering the active site of glycogen phosphorylase. What are the advantages of
excluding water from the active site? - correct answer ✔✔-to maintain energy supplies in muscle cells
-to prevent the formation of glucose
-to prevent energy waste by conserving the ATP that would be needed to phosphorylate glucose
In the liver, stimulation of the glucagon receptor leads to - correct answer ✔✔-activation of PKA
-activation of glycogen phosphorylase
-conversion of ATP to cAMP
-activation of fructose 1,6-biphosphatase
Regardless of its efficacy, what is the reasoning behind carbohydrate loading? - correct answer
✔✔Glucose is stored as glycogen, which can be broken down to supply energy during the event.
Select all of the carbohydrate pathways that glucagon stimulates in the liver. - correct answer
✔✔gluconeogenesis and glycogen breakdown
Glycogen phosphorylase in muscle - correct answer ✔✔-activation generates glucose for the cell
-b form is the default state
-AMP binding induces R state
