BMSC 230 Final Exam (Comprehensive)
with Complete Solutions
10 steps of glycolysis - step 1 - ANSWER-Hexokinase: adds a phosphate onto glucose -
forms glucose-6-P
• irreversible energy consumption step
• phosphorylation traps glucose in the cell
10 steps of glycolysis - step 10 - ANSWER-Pyruvate kinase: removes the phosphate
group from phosphoenolpyruvate and gives it to ADP
• forms 2 ATP & 2 Pyruvate
• irreversible step
10 steps of glycolysis - step 2 - ANSWER-Phosphoglucose isomerase: converts
glucose-6-P into fructose-6-P
• rearranges covalent bonds
• reversible Reaction
10 steps of glycolysis - step 3 - ANSWER-Phosphofructokinase: removes a phosphate
from ATP and gives it to fructose-6-P, forms fructose-1,6-BisP
• irreversible energy consumption step
10 steps of glycolysis - step 4 - ANSWER-Lyase - fructose bisphosphate aldose:
cleaves 6-carbon fructose-1,6-BisP by aldolase into 2 3-carbon sugars
• Dihydroxyacetone P
• Glyceraldehyde-3-P
10 steps of glycolysis - step 5 - ANSWER-Triosephosphate isomerase:
dihydroxyacetone P is rearranged to form another glyceraldehyde-3-P
• reversible reaction
10 steps of glycolysis - step 6 - ANSWER-Dehydrogenase: both glyceraldehyde-3-P are
oxidized to 1,3-Bisphosphoglycerate by a dehydrogenase
• produces 1 NADH for each - 2 total
10 steps of glycolysis - step 7 - ANSWER-Phsophoglycerate kinase: transfers a
phosphate from 1,3-Bisphosphoglycerate to ADP
• forms 2 ATP & 3-phosphoglycerate
• reversible energy producing step
10 steps of glycolysis - step 8 - ANSWER-Phosphoglycerate mutase: moves the
phosphate on the third carbon on 3-phosphoglycerate to the second carbon to form 2-
phosphoglycerate
,10 steps of glycolysis - step 9 - ANSWER-Lyase - Enolase: removes H2O from 2-
phosphoglycerate to form phosphoenolpyruvate
2,4-dinitrophenol - ANSWER-Discovered during WWI - used for weight loss, eventually
found to have many adverse side effects including blindness, changes in liver, heart &
muscle function
3 cytosolic enzymes - argininosuccinate synthetase, argininosuccinase & arginase -
ANSWER-Are clustered together in a complex
• keeps pathway intermediated in/near the complex - products quickly passed to next
enzyme = high local [ ] of intermediates = inc rate of urea cycle
• keeping sequestered = no side reactions which would slow the rate of flux through the
urea cycle
3 enzyme catalyzed reactions involves in step 2 of nitrogen assimilation - ANSWER-1.
Via glutamate dehydrogenase
• NH4+ + a-ketoglutarate <—> glutamate
• ammonium used as a source of N
• either NADH or NADPH used
2. Via glutamate synthetase
• glutamate + NH4+ + ATP -> glutamine + ADP + Pi + H+
• glutamate used to assimilate more N
3. Via glutamate synthase
• a-ketoglutarate + glutamine + NADPH + H+ -> 2 glutamate + NADP+
3 kinds of ketone bodies produced by acetyl CoA - ANSWER-3-hydroxybutyrate (B-
hydroxybutyrate)
Acetoacetate
Acetone
3 lipases involved in triacylglycerol degradation - ANSWER-1. acts on triacylglycerol (3
fatty acids attached)
2. acts on diacylglycerol (2 fatty acids attached)
3. acts on monoacylglycerol (1 fatty acid attached)
3 primary ways in which metabolic pathways are regulated - ANSWER-1. The amount
of an enzyme that catalyzes a regulated step in the pathway can be regulated itself
• control amount of enzyme - affecting what/how much it codes for
2. The catalytic activity of the enzyme can be regulated - allosteric regulation binding
inhibitors or activators = dec enzyme activity & enzymes covalently modified
3. Controlling the availability of substrates
3 protons need to enter through - ANSWER-ATP synthase to generate enough energy
to synthesize ATP from ADP & Pi
• 1 proton is added to ATP synthase from outside the inner membrane, and a second is
released inside the inner membrane (matrix)
,• process continues as a gradient is always maintained (as long as ATP is needed)
3 types of metabolic pathways - ANSWER-Linear - straight line
• substrate —> product —> product —> final product
Branched - starts off linear and an intermediate leads to different branched pathways
Circular - the starting biomolecule is the finish biomolecule
• citric acid cycle
3 unique components of gluconeogenesis that overcome the 3 irreversible steps of
glycolysis - ANSWER-Pyruvate —> Oxaloacetate
• via Pyruvate carboxylase & ATP Hydrolysis
• oxaloacetate is catalyzed to form phosphoenolpyruvate via PEP carboxykinase & GTP
Fructose-1,6-BisP —> Fructose-6-P
• via fructose-1,6-Bisphosphatase
Glucose-6-Phosphate —> Glucose
• via glucose-6-phosphatase
3-hydroxybutyrate & acetoacetate - ANSWER-Are metabolized to acetyl CoA - Krebs
4 primary functions of metabolism - ANSWER-1. Obtain chemical energy in the form of
ATP
• from energy rich nutrients, or solar energy
2. Convert ingested molecules into the building blocks of larger molecules needed in the
body
3. Assemble small building blocks into large building molecules
• protein, nucleic acids, lipids, polysaccharides
4. Synthesize and degrade biomolecules that have specialized functions in cells
A combination of covalent modifications & allosteric inhibitors - ANSWER-Is required to
control the activity of glutamine synthetase
A high concentration of ADP inhibits gluconeogenesis - ANSWER-Gluconeogenesis
requires high energy - ATP
A major issue vertebrates face when synthesizing any nitrogen containing molecule -
ANSWER-Is the fact that they are not able to fix nitrogen into a usable form
• rely on bac to assimilate nitrogen into a usable form (80% of air breathed is N2)
A major reoccurring theme in metabolism is - ANSWER-Activated carriers
A simple way to calculate the concentration of the reactants and products when the
reaction has reached equilibrium and deltaG is 0 - ANSWER-deltaG•' = -RT Keq —>
deltaG•' = -2.3RT log Keq
Keq = ([prod]/[react])
, A single glycogen granule can have - ANSWER-Up to 30,000 glucose units
a-ketoacids that are produced via transmination - ANSWER-Are further metabolized
through several steps - used to form fuels (glucose, fatty acids) or oxidized completely
through Krebs to produce ATP
a-Ketoglutarate is oxidized & decarboxylated to - ANSWER-Succinyl CoA via a-
ketoglutarate dehydrogenase
• high energy electrons captured as NADH
• CO2 is released
About 2-4% of oxygen molecules - ANSWER-Are converted to superoxide ions in the
mitochondria
About 60% of N Americans - ANSWER-Experience gastroesophageal reflux disease
(GERD) - heartburn
• chronic heartburn should NOT be ignored - can result in scarring/narrowing of the
esophagus - problems with swallowing/lead to cancer
Acetoacetate plays a regulatory role - ANSWER-In fatty acid metabolism
• high levels of acetoacetate indicate an abundance of acetyl CoA which acts on
adipose tissue to inhibit lipolysis
Acetone - ANSWER-Is less abundant & more volatile
• mostly exhaled through the lungs
Acetyl CoA (2-C) condenses with - ANSWER-A 4-C Oxaloacetate to make a 6-C Citrate
via citrate synthase
Acetyl CoA carboxylase - ANSWER-Is a key regulator of fatty acid metabolism
Acetyl CoA carboxylase & fatty acid synthesis - ANSWER-Is stimulated by insulin
• insulin is released in response to ingestion - substrates (carbohydrates) for fatty acid
synthesis will be high
Acetyl CoA carboxylase is allosterically - ANSWER-Activated by citrate
• citrate reflects the energy state of the cell - high levels = sufficient energy for
biosynthesis
• citrate carries acetyl CoA to the cytosol (from matrix) = available for synthesis
Acetyl CoA produced by any means - ANSWER-Can enter the citric acid cycle
• used to generate ATP
• breakdown of some fats & amino acids result in acetyl CoA
Acetyl CoA produced by fatty acids - ANSWER-Can enter directly to the citric acid cycle
b/c B-oxidation occurs in the mitochondrial matrix
with Complete Solutions
10 steps of glycolysis - step 1 - ANSWER-Hexokinase: adds a phosphate onto glucose -
forms glucose-6-P
• irreversible energy consumption step
• phosphorylation traps glucose in the cell
10 steps of glycolysis - step 10 - ANSWER-Pyruvate kinase: removes the phosphate
group from phosphoenolpyruvate and gives it to ADP
• forms 2 ATP & 2 Pyruvate
• irreversible step
10 steps of glycolysis - step 2 - ANSWER-Phosphoglucose isomerase: converts
glucose-6-P into fructose-6-P
• rearranges covalent bonds
• reversible Reaction
10 steps of glycolysis - step 3 - ANSWER-Phosphofructokinase: removes a phosphate
from ATP and gives it to fructose-6-P, forms fructose-1,6-BisP
• irreversible energy consumption step
10 steps of glycolysis - step 4 - ANSWER-Lyase - fructose bisphosphate aldose:
cleaves 6-carbon fructose-1,6-BisP by aldolase into 2 3-carbon sugars
• Dihydroxyacetone P
• Glyceraldehyde-3-P
10 steps of glycolysis - step 5 - ANSWER-Triosephosphate isomerase:
dihydroxyacetone P is rearranged to form another glyceraldehyde-3-P
• reversible reaction
10 steps of glycolysis - step 6 - ANSWER-Dehydrogenase: both glyceraldehyde-3-P are
oxidized to 1,3-Bisphosphoglycerate by a dehydrogenase
• produces 1 NADH for each - 2 total
10 steps of glycolysis - step 7 - ANSWER-Phsophoglycerate kinase: transfers a
phosphate from 1,3-Bisphosphoglycerate to ADP
• forms 2 ATP & 3-phosphoglycerate
• reversible energy producing step
10 steps of glycolysis - step 8 - ANSWER-Phosphoglycerate mutase: moves the
phosphate on the third carbon on 3-phosphoglycerate to the second carbon to form 2-
phosphoglycerate
,10 steps of glycolysis - step 9 - ANSWER-Lyase - Enolase: removes H2O from 2-
phosphoglycerate to form phosphoenolpyruvate
2,4-dinitrophenol - ANSWER-Discovered during WWI - used for weight loss, eventually
found to have many adverse side effects including blindness, changes in liver, heart &
muscle function
3 cytosolic enzymes - argininosuccinate synthetase, argininosuccinase & arginase -
ANSWER-Are clustered together in a complex
• keeps pathway intermediated in/near the complex - products quickly passed to next
enzyme = high local [ ] of intermediates = inc rate of urea cycle
• keeping sequestered = no side reactions which would slow the rate of flux through the
urea cycle
3 enzyme catalyzed reactions involves in step 2 of nitrogen assimilation - ANSWER-1.
Via glutamate dehydrogenase
• NH4+ + a-ketoglutarate <—> glutamate
• ammonium used as a source of N
• either NADH or NADPH used
2. Via glutamate synthetase
• glutamate + NH4+ + ATP -> glutamine + ADP + Pi + H+
• glutamate used to assimilate more N
3. Via glutamate synthase
• a-ketoglutarate + glutamine + NADPH + H+ -> 2 glutamate + NADP+
3 kinds of ketone bodies produced by acetyl CoA - ANSWER-3-hydroxybutyrate (B-
hydroxybutyrate)
Acetoacetate
Acetone
3 lipases involved in triacylglycerol degradation - ANSWER-1. acts on triacylglycerol (3
fatty acids attached)
2. acts on diacylglycerol (2 fatty acids attached)
3. acts on monoacylglycerol (1 fatty acid attached)
3 primary ways in which metabolic pathways are regulated - ANSWER-1. The amount
of an enzyme that catalyzes a regulated step in the pathway can be regulated itself
• control amount of enzyme - affecting what/how much it codes for
2. The catalytic activity of the enzyme can be regulated - allosteric regulation binding
inhibitors or activators = dec enzyme activity & enzymes covalently modified
3. Controlling the availability of substrates
3 protons need to enter through - ANSWER-ATP synthase to generate enough energy
to synthesize ATP from ADP & Pi
• 1 proton is added to ATP synthase from outside the inner membrane, and a second is
released inside the inner membrane (matrix)
,• process continues as a gradient is always maintained (as long as ATP is needed)
3 types of metabolic pathways - ANSWER-Linear - straight line
• substrate —> product —> product —> final product
Branched - starts off linear and an intermediate leads to different branched pathways
Circular - the starting biomolecule is the finish biomolecule
• citric acid cycle
3 unique components of gluconeogenesis that overcome the 3 irreversible steps of
glycolysis - ANSWER-Pyruvate —> Oxaloacetate
• via Pyruvate carboxylase & ATP Hydrolysis
• oxaloacetate is catalyzed to form phosphoenolpyruvate via PEP carboxykinase & GTP
Fructose-1,6-BisP —> Fructose-6-P
• via fructose-1,6-Bisphosphatase
Glucose-6-Phosphate —> Glucose
• via glucose-6-phosphatase
3-hydroxybutyrate & acetoacetate - ANSWER-Are metabolized to acetyl CoA - Krebs
4 primary functions of metabolism - ANSWER-1. Obtain chemical energy in the form of
ATP
• from energy rich nutrients, or solar energy
2. Convert ingested molecules into the building blocks of larger molecules needed in the
body
3. Assemble small building blocks into large building molecules
• protein, nucleic acids, lipids, polysaccharides
4. Synthesize and degrade biomolecules that have specialized functions in cells
A combination of covalent modifications & allosteric inhibitors - ANSWER-Is required to
control the activity of glutamine synthetase
A high concentration of ADP inhibits gluconeogenesis - ANSWER-Gluconeogenesis
requires high energy - ATP
A major issue vertebrates face when synthesizing any nitrogen containing molecule -
ANSWER-Is the fact that they are not able to fix nitrogen into a usable form
• rely on bac to assimilate nitrogen into a usable form (80% of air breathed is N2)
A major reoccurring theme in metabolism is - ANSWER-Activated carriers
A simple way to calculate the concentration of the reactants and products when the
reaction has reached equilibrium and deltaG is 0 - ANSWER-deltaG•' = -RT Keq —>
deltaG•' = -2.3RT log Keq
Keq = ([prod]/[react])
, A single glycogen granule can have - ANSWER-Up to 30,000 glucose units
a-ketoacids that are produced via transmination - ANSWER-Are further metabolized
through several steps - used to form fuels (glucose, fatty acids) or oxidized completely
through Krebs to produce ATP
a-Ketoglutarate is oxidized & decarboxylated to - ANSWER-Succinyl CoA via a-
ketoglutarate dehydrogenase
• high energy electrons captured as NADH
• CO2 is released
About 2-4% of oxygen molecules - ANSWER-Are converted to superoxide ions in the
mitochondria
About 60% of N Americans - ANSWER-Experience gastroesophageal reflux disease
(GERD) - heartburn
• chronic heartburn should NOT be ignored - can result in scarring/narrowing of the
esophagus - problems with swallowing/lead to cancer
Acetoacetate plays a regulatory role - ANSWER-In fatty acid metabolism
• high levels of acetoacetate indicate an abundance of acetyl CoA which acts on
adipose tissue to inhibit lipolysis
Acetone - ANSWER-Is less abundant & more volatile
• mostly exhaled through the lungs
Acetyl CoA (2-C) condenses with - ANSWER-A 4-C Oxaloacetate to make a 6-C Citrate
via citrate synthase
Acetyl CoA carboxylase - ANSWER-Is a key regulator of fatty acid metabolism
Acetyl CoA carboxylase & fatty acid synthesis - ANSWER-Is stimulated by insulin
• insulin is released in response to ingestion - substrates (carbohydrates) for fatty acid
synthesis will be high
Acetyl CoA carboxylase is allosterically - ANSWER-Activated by citrate
• citrate reflects the energy state of the cell - high levels = sufficient energy for
biosynthesis
• citrate carries acetyl CoA to the cytosol (from matrix) = available for synthesis
Acetyl CoA produced by any means - ANSWER-Can enter the citric acid cycle
• used to generate ATP
• breakdown of some fats & amino acids result in acetyl CoA
Acetyl CoA produced by fatty acids - ANSWER-Can enter directly to the citric acid cycle
b/c B-oxidation occurs in the mitochondrial matrix
