BIOC 385 Exam 2 Questions and Answers Already Passed Latest Update 2025-2026
Which one of the following is involved in the breakdown of glycogen? - Answers inorganic
phosphate
Which enzyme catalyzes the formation of alpha(1,6) linkages during glycogen synthesis? -
Answers glycogen branching enzyme
McArdle disease is due to a deficiency in muscle glycogen phosphorylase activity. The result of
this deficiency is an inability to_________________. - Answers form glucose-1-phosphate.
Which one of the fatty acids shown below corresponds to a polyunsaturated fatty acid? -
Answers
The branching enzyme in glycogen synthesis ________________. - Answers catalyzes the cleavage
of (1,4) links and the formation of (1,6) links.
The fatty acid structure shown below is that of a _______________ fatty acid. - Answers saturated
Pork fat has a melting temperature of 40ºC and flaxseed oil has a melting temperature of -25ºC.
What contributes to this ~65ºC difference in melting temperature? Choose the ONE best answer.
- Answers Pork fat contains 40% palmitate and stearate, whereas flaxseed oil is 53% alpha-
linolenate, the difference in average a melting temperature is about 65ºC, so it makes sense.
The activation of glycogen phosphorylase will lead to a(n) __________ in blood glucose
concentrations and is stimulated by the hormone __________. - Answers increase; glucagon
Insulin stimulates __________ and inhibits __________, leading to a(n) __________ in the glucose
levels. - Answers glycogen synthase; glycogen phosphorylase; decrease
Partial hydrogenation can result in the formation of_______________. - Answers trans double
bonds.
Answer the following three questions regarding net ATP yields in glycolysis:
a) What is the net yield of ATP in the glycolytic pathway when glucose is derived from the diet?
b) What is the net yield of ATP in the glycolytic pathway when glucose is derived from glycogen
degradation?
c) What accounts for the difference in net ATP yield? - Answers a) 2 ATP
b) 3 ATP
c) only 1 ATP investment is required for glucose derived from glycogen degradation
What is the biochemical basis for McArdle Disease? - Answers It is due to a defect in the
muscle glycogen phosphorylase enzyme.
,What explains why glycogen phosphorylase reaction is energetically favorable (delta G = -6
kJ/mol) even though the standard change in free energy is unfavorable (delta Gº' = +3.1 kJ/mol)?
- Answers Because [Pi] >> [glucose-1P]
Identify the the three enzymes in the figure below (1, 2, 3) and describe their primary function. -
Answers Enz 1: glycogen phosphorylase; generates glucose-1P
Enz 2: phosphoglucomutase; generates glucose-6P
Enz 3: debranching enzyme: generates glucose
Epinephrine signaling in muscle cells activates protein kinase A (PKA), which phosphorylates
three downstream proteins 1) phosphorylase kinase, 2) the protein phosphatase 1 (PP1)
regulatory protein GM, and 3) Inhibitor 1 (Inh-1) protein, which binds to PP1 to block its activity. -
Answers __6__Glycogen synthase is phosphorylated and its catalytic activity is inhibited.
__5__Inh-1 binds to PP1 and inhibits its association with GM protein.
__1__Epinephrine signaling stimulates the production of cAMP.
__3__PKA phosphorylates; a) GM protein on S2 site, b) Inh-1, c) phosphorylase kinase.
__4__Phosphorylase kinase phosphorylates glycogen phosphorylase.
__7__Glycogen degradation is turned ON; glycogen synthesis is turned OFF.
__2__cAMP binding to PKA regulatory subunit stimulates PKA kinase activity.
The enzymes protein kinase A (PKA) and protein phosphatase 1 (PP1) play critical roles in
regulating glycogen metabolism in muscle cells in response to insulin signaling, which leads to
phosphorylation of the regulatory protein GM. - Answers __2__Insulin-stimulated PK1
phosphorylates GM protein on the S1 site.
__6__Inh-1 is unphosphorylated and does not bind to PP1 to block its activity.
__7__Glycogen synthesis is turned ON; glycogen degradation is turned OFF.
__3__Phosphorylated GM protein binds to PP1 and stimulates its activity.
__5__Glycogen synthase is activated and glycogen phosphorylase is inhibited.
__1__Insulin signaling stimulates the activity of insulin-stimulated PK1.
__4__PP1 dephosphorylates glycogen synthase and glycogen phosphorylase.
Identify the four major classes of arachidonate-derived eicosanoids. - Answers Prostaglandins
Leukotrienes
, Prostacyclins
Thrombaxanes
Identify each of the following NSAIDs and determine if they are likely to be a COX-1 (C1), COX-2
(C2), or COX-1/COX-2 (C-1.2) inhibitor. Draw out their structures. - Answers A. naproxen (C1.2)
B. rofecoxib (C2)
C. aspirin (C1.2)
D. flurbiprofen (C1.2)
E. ibuprofen (C1.2)
F. celecoxib (C2)
Why is celecoxib selective for COX-2 inhibition as compared to COX-1 inhibition? - Answers COX
-1 contains Ile-523, whereas COX-2 contains Val-523, which permits celecoxib binding.
What is thought to be responsible for the increased risk of cardiovascular disease caused by
some selective COX-2 inhibitors? - Answers Inhibition of prostacyclin synthase, leading to
increased blood clot formation.
Prostaglandins produced by COX-1 are responsible for _________ (1), whereas prostaglandins
produced by the COX-2 enzyme are responsible for ______________(2). - Answers (1) stimulating
mucin production
(2) swelling, pain, and fever
What controls the bioavailability of arachidonate in the eicosanoid signaling pathway? - Answers
GPCR activation of phospholipase A2 leads to cleavage of membrane lipids to produce
arachidonate.
What is glycogen? - Answers highly branched polymer of glucose that is degraded to yield
glucose-1P which is isomerized to glucose-6P.
What does glycogen phosphorylase do? - Answers It removes one glucose at a time from the
nonreducing ends using inorganic phosphate.
What does glycogen synthase do? - Answers It adds glucose in a reaction involving UDP-
glucose.
What does the inorganic phosphate do? - Answers It is used to generate glucose-1-P when
glycogen is degraded is free because it does not require an ATP investment to generate the
glucose-6-P for glycolysis.
How many ATP does glycogen synthesis require? - Answers It requires 1 ATP net investment
Which one of the following is involved in the breakdown of glycogen? - Answers inorganic
phosphate
Which enzyme catalyzes the formation of alpha(1,6) linkages during glycogen synthesis? -
Answers glycogen branching enzyme
McArdle disease is due to a deficiency in muscle glycogen phosphorylase activity. The result of
this deficiency is an inability to_________________. - Answers form glucose-1-phosphate.
Which one of the fatty acids shown below corresponds to a polyunsaturated fatty acid? -
Answers
The branching enzyme in glycogen synthesis ________________. - Answers catalyzes the cleavage
of (1,4) links and the formation of (1,6) links.
The fatty acid structure shown below is that of a _______________ fatty acid. - Answers saturated
Pork fat has a melting temperature of 40ºC and flaxseed oil has a melting temperature of -25ºC.
What contributes to this ~65ºC difference in melting temperature? Choose the ONE best answer.
- Answers Pork fat contains 40% palmitate and stearate, whereas flaxseed oil is 53% alpha-
linolenate, the difference in average a melting temperature is about 65ºC, so it makes sense.
The activation of glycogen phosphorylase will lead to a(n) __________ in blood glucose
concentrations and is stimulated by the hormone __________. - Answers increase; glucagon
Insulin stimulates __________ and inhibits __________, leading to a(n) __________ in the glucose
levels. - Answers glycogen synthase; glycogen phosphorylase; decrease
Partial hydrogenation can result in the formation of_______________. - Answers trans double
bonds.
Answer the following three questions regarding net ATP yields in glycolysis:
a) What is the net yield of ATP in the glycolytic pathway when glucose is derived from the diet?
b) What is the net yield of ATP in the glycolytic pathway when glucose is derived from glycogen
degradation?
c) What accounts for the difference in net ATP yield? - Answers a) 2 ATP
b) 3 ATP
c) only 1 ATP investment is required for glucose derived from glycogen degradation
What is the biochemical basis for McArdle Disease? - Answers It is due to a defect in the
muscle glycogen phosphorylase enzyme.
,What explains why glycogen phosphorylase reaction is energetically favorable (delta G = -6
kJ/mol) even though the standard change in free energy is unfavorable (delta Gº' = +3.1 kJ/mol)?
- Answers Because [Pi] >> [glucose-1P]
Identify the the three enzymes in the figure below (1, 2, 3) and describe their primary function. -
Answers Enz 1: glycogen phosphorylase; generates glucose-1P
Enz 2: phosphoglucomutase; generates glucose-6P
Enz 3: debranching enzyme: generates glucose
Epinephrine signaling in muscle cells activates protein kinase A (PKA), which phosphorylates
three downstream proteins 1) phosphorylase kinase, 2) the protein phosphatase 1 (PP1)
regulatory protein GM, and 3) Inhibitor 1 (Inh-1) protein, which binds to PP1 to block its activity. -
Answers __6__Glycogen synthase is phosphorylated and its catalytic activity is inhibited.
__5__Inh-1 binds to PP1 and inhibits its association with GM protein.
__1__Epinephrine signaling stimulates the production of cAMP.
__3__PKA phosphorylates; a) GM protein on S2 site, b) Inh-1, c) phosphorylase kinase.
__4__Phosphorylase kinase phosphorylates glycogen phosphorylase.
__7__Glycogen degradation is turned ON; glycogen synthesis is turned OFF.
__2__cAMP binding to PKA regulatory subunit stimulates PKA kinase activity.
The enzymes protein kinase A (PKA) and protein phosphatase 1 (PP1) play critical roles in
regulating glycogen metabolism in muscle cells in response to insulin signaling, which leads to
phosphorylation of the regulatory protein GM. - Answers __2__Insulin-stimulated PK1
phosphorylates GM protein on the S1 site.
__6__Inh-1 is unphosphorylated and does not bind to PP1 to block its activity.
__7__Glycogen synthesis is turned ON; glycogen degradation is turned OFF.
__3__Phosphorylated GM protein binds to PP1 and stimulates its activity.
__5__Glycogen synthase is activated and glycogen phosphorylase is inhibited.
__1__Insulin signaling stimulates the activity of insulin-stimulated PK1.
__4__PP1 dephosphorylates glycogen synthase and glycogen phosphorylase.
Identify the four major classes of arachidonate-derived eicosanoids. - Answers Prostaglandins
Leukotrienes
, Prostacyclins
Thrombaxanes
Identify each of the following NSAIDs and determine if they are likely to be a COX-1 (C1), COX-2
(C2), or COX-1/COX-2 (C-1.2) inhibitor. Draw out their structures. - Answers A. naproxen (C1.2)
B. rofecoxib (C2)
C. aspirin (C1.2)
D. flurbiprofen (C1.2)
E. ibuprofen (C1.2)
F. celecoxib (C2)
Why is celecoxib selective for COX-2 inhibition as compared to COX-1 inhibition? - Answers COX
-1 contains Ile-523, whereas COX-2 contains Val-523, which permits celecoxib binding.
What is thought to be responsible for the increased risk of cardiovascular disease caused by
some selective COX-2 inhibitors? - Answers Inhibition of prostacyclin synthase, leading to
increased blood clot formation.
Prostaglandins produced by COX-1 are responsible for _________ (1), whereas prostaglandins
produced by the COX-2 enzyme are responsible for ______________(2). - Answers (1) stimulating
mucin production
(2) swelling, pain, and fever
What controls the bioavailability of arachidonate in the eicosanoid signaling pathway? - Answers
GPCR activation of phospholipase A2 leads to cleavage of membrane lipids to produce
arachidonate.
What is glycogen? - Answers highly branched polymer of glucose that is degraded to yield
glucose-1P which is isomerized to glucose-6P.
What does glycogen phosphorylase do? - Answers It removes one glucose at a time from the
nonreducing ends using inorganic phosphate.
What does glycogen synthase do? - Answers It adds glucose in a reaction involving UDP-
glucose.
What does the inorganic phosphate do? - Answers It is used to generate glucose-1-P when
glycogen is degraded is free because it does not require an ATP investment to generate the
glucose-6-P for glycolysis.
How many ATP does glycogen synthesis require? - Answers It requires 1 ATP net investment
