ACS BIOCHEMISTRY EXAM Questions
and Verified Solutions 2024
2-carboxyarabinitol 1-phosphate - Answer -inhibits carbamoylated rubisco. Synthesized in the dark and is
broken down by rubisco activase or light.
A-form DNA - Answer -Condensed form of DNA. Deeper major groove and shallower minor groove.
ACC (acetyl-CoA carboxylase) Regulation - Answer -Inhibited by PKA in glucagon chain and activated by
pjhosphatase in INSR chain.
Additional Cost of FAS in Eukaryotes - Answer -Acetyl-CoA for lipid synthesis is made in mitochondria and
must be transferred into the cytosol via citrate transporter. Costs 2 ATP.
Affinity Chromatography - Answer -Attach a ligand that binds a protein to a bead. Elute with harsh
chemicals or similar ligand.
AKAP - Answer -Anchoring protein that binds to PKA, GPCR, and adenylyl cyclase.
Amidotransferase - Answer -Uses a PLP group to transfer amino group from an amino acid to α-
ketoglutarate to form L-glutamate and an α-ketoglutarate.
Ammonia (NH4+) Transportation - Answer -L-glutamate is converted to L-glutamine via glutamine
synthetase.
ATP + NH4+ --> ADP + Pi
L-glutamine can be converted back to L-glutamate in the liver.
Amylopectin - Answer -Has α-1,4-linkages. Has periodic α-1,6-linkages that cause branching. Branched
every 24-30 residues. Has reducing and non-reducing end.
Amylose Chain - Answer -Has α-1,4-linkages that produce a coiled helix similar to an α-helix. Has a
reducing and non-reducing end.
Anaerobic Ammonia Oxidation (Anammox) - Answer -Ability of some bacteria to oxidize NH4+ and NO2-
into N2. "Short-circuits" the nitrogen cycle.
Anomeric Carbon - Answer -Carbon that is cyclized. Always the same as the aldo or keto carbon in the
linear form.
,Anti-parallel ß-sheet - Answer -Alternating sheet directions (C & N-termini don't line-up). Has straight H-
bonds.
ATP Consuming Steps of Glycolysis - Answer -Step 1 and 3.
Glucose --> Glucose 6-phosphate
Fructose 6-phosphate --> Fructose 1,6-bisphosphate
ATP Producing Steps of Glycolysis - Answer -Steps 7 and 10.
1,3-bisphosphoglycerate <--> 3-phosphoglycerate
PEP --> Pyruvate
B-form DNA - Answer -Watson-Crick model DNA. Deep, wide major groove.
Bacteriorhodopsin - Answer -Type III integral membrane protein with 7 connected helices.
Binding Cooperativity - Answer -When one subunit of hemoglobin changes from T to R-state the other
sites are more likely to change to R-state as well. Leads to sigmoidal graph.
Biotin Function - Answer -Prosthetic group that serves as a CO2 carrier to separate active sites on an
enzyme
Biotin Structure - Answer -
BPG (2,3-bisphosphoglycerate) - Answer -Greatly reduces hemoglobin's affinity for O2 by binding
allosterically. Stabilizes T-state. Transfer of O2 can improve because increased delivery in tissues can
outweigh decreased binding in the lungs.
Bypass Reactions in Gluconeogenesis - Answer -Steps 1,3, and 10 must be bypassed.
C4 Plants - Answer -Fix CO2 into PEP to form oxaloacetate (via PEP carboxykinase) that is then converted
to malate that carries CO2 to rubisco. Bypasses O2 binding.
CAM plants - Answer -Fix CO2 into PEP to form oxaloacetate (via PEP carboxykinase) that is converted to
malate at night and stored until the day time.
cAMP - Answer -Secondary messenger in GPCR signalling. Formed from ATP by adenylyl cyclase.
Activates PKA (protein kinase A).
Cardiolipin - Answer -"Lipid staple" that ties two proteins (or complexes) together in a membrane.
Formed from two phosphoglycerols.
Cellulose - Answer -Comes from plants. Poly D-glucose. Formed from ß-1,4-linkage. Form sheets due to
equatorial -OH groups that H-bond with other chains.
,Chargaff's Rule - Answer -Ratio of A:T and G:C are always equal or close to 1
Chitin - Answer -Homopolymer of N-acetyl-ß-D-glucosamine. Have ß-1,4-linkages. Found in lobsters,
squid beaks, beetle shells, etc.
Cholesterol Synthesis - Answer -Synthesized from 15 acetyl-CoA through a number of intermediates.
Chymotripsin - Answer -Cleaves proteins on C-terminal endof Phe, Trp, and Tyr
Circular Dichroism - Answer -Uses UV light to measure 2° structure. Can be used to measure
destabilization.
CO2 binding in Hemoglobin - Answer -Forms carbonic acid that shifts hemoglobin to T-state. O2 binding
affinity decreases. Used in the peripheral tissues.
CO2 Producing Steps of the Citric Acid Cycle - Answer -Steps 3 and 4
Isocitrate --> α-ketoglutarate
α-ketoglutarate --> Succinyl-CoA
Collagen - Answer -Repeating sequence of Gly-X-Pro. 3 stranded "coiled coil". Contains gly core.
Competitive Inhibition Graph - Answer -Slope changes by factor of α. Slope becomes αKm/Vmax.
X-intercept becomes 1/αKm
Y-intercept does not change.
Vmax does not change.
Complex I in the ETC - Answer -Accepts two electrons from NADH via an FMN cofactor. Transfers 4H+ to
Pside and 2H+ to Q
Complex II in the ETC - Answer -Succinate dehydrogenase. Accepts two electrons electrons from
succinate via an FAD group. Q --> QH2
Complex III in the ETC - Answer -Transfers two electrons from QH2 to cytochrome c via the Q-cycle.
Transfers 4H+ to Pside.
Complex IV in the ETC - Answer -Transfers electrons from cytochrome c to O2. Four electrons are used to
reduce on O2 into two H2O molecules. Transfers 4H+ to Pside
Cooperative Protein Folding - Answer -Folding transition is sharp. More reversible.
Cost of FAS in Eukaryotes - Answer -3 ATP's per 2 carbon unit added.
Cost of Gluconeogenesis - Answer -4 ATP, 2 GTP, and 2 NADH
, Different Steps in the Glyoxylate Cycle - Answer -Isocitrate --> Glyoxylate (+ succinate)
Uses isocitrate lyase
Glyoxylate (+ acetyl-coA) --> Malate
Uses malate synthase
Dihydrolipoyl Transacetylase - Answer -E2 domain of the PDH complex. Catalyzes formation of Acetyl-
CoA. Has oxidized, acyl, and reduced lipoyllysine.
Dihydrolipyl Dehydrogenase - Answer -E3 domain of the PDH complex. Catalyzes regeneration of the
lipoyllysine using FAD --> FADH2
Disulfide-bonds - Answer -Bonds between two -SH groups that form between 2° and 3° structure.
DNA Base-paring - Answer -G-C base pairs have 3 H-bonds
A-T base pairs have 2 H-bonds
DNA Double-Helix - Answer -Opposite strand direction. 3.4Å distance between complementary bases.
36Å for one complete turn.
DNA UV Absorbtion - Answer -Absorbs UV light at 260nm.
DTT (dithiothreitol) - Answer -Reduces disulfide bonds.
Energy Consumption of the Calvin Cycle - Answer -9 ATP molecules and 6 NADPH molecules for every 3
CO2 molecules that are fixated.
Enzyme Km and Substrate Concentration - Answer -Most enzymes have a Km that is near the
concentration of the substrate.
ETC (Electron Transport Chain) - Answer -Consists of 4 functional protein complexes.
Ethanol Fermentation - Answer -Pyruvate --> Acetalaldehyde --> Ethanol
Uses pyruvate decarboxylase (TPP) and alcohol dehydrogenase.
NADH --> CO2(TPP) + NAD+
F0 Domain of Mitochondrial ATP Synthase - Answer -Causes rotation of γ-subunit via a half channel and
H+ gradient
F1 Domain of Mitochondrial ATP Synthase - Answer -Hexamer of 3 αß dimers. Catalyze ADP + Pi --> ATP
via binding-change model
and Verified Solutions 2024
2-carboxyarabinitol 1-phosphate - Answer -inhibits carbamoylated rubisco. Synthesized in the dark and is
broken down by rubisco activase or light.
A-form DNA - Answer -Condensed form of DNA. Deeper major groove and shallower minor groove.
ACC (acetyl-CoA carboxylase) Regulation - Answer -Inhibited by PKA in glucagon chain and activated by
pjhosphatase in INSR chain.
Additional Cost of FAS in Eukaryotes - Answer -Acetyl-CoA for lipid synthesis is made in mitochondria and
must be transferred into the cytosol via citrate transporter. Costs 2 ATP.
Affinity Chromatography - Answer -Attach a ligand that binds a protein to a bead. Elute with harsh
chemicals or similar ligand.
AKAP - Answer -Anchoring protein that binds to PKA, GPCR, and adenylyl cyclase.
Amidotransferase - Answer -Uses a PLP group to transfer amino group from an amino acid to α-
ketoglutarate to form L-glutamate and an α-ketoglutarate.
Ammonia (NH4+) Transportation - Answer -L-glutamate is converted to L-glutamine via glutamine
synthetase.
ATP + NH4+ --> ADP + Pi
L-glutamine can be converted back to L-glutamate in the liver.
Amylopectin - Answer -Has α-1,4-linkages. Has periodic α-1,6-linkages that cause branching. Branched
every 24-30 residues. Has reducing and non-reducing end.
Amylose Chain - Answer -Has α-1,4-linkages that produce a coiled helix similar to an α-helix. Has a
reducing and non-reducing end.
Anaerobic Ammonia Oxidation (Anammox) - Answer -Ability of some bacteria to oxidize NH4+ and NO2-
into N2. "Short-circuits" the nitrogen cycle.
Anomeric Carbon - Answer -Carbon that is cyclized. Always the same as the aldo or keto carbon in the
linear form.
,Anti-parallel ß-sheet - Answer -Alternating sheet directions (C & N-termini don't line-up). Has straight H-
bonds.
ATP Consuming Steps of Glycolysis - Answer -Step 1 and 3.
Glucose --> Glucose 6-phosphate
Fructose 6-phosphate --> Fructose 1,6-bisphosphate
ATP Producing Steps of Glycolysis - Answer -Steps 7 and 10.
1,3-bisphosphoglycerate <--> 3-phosphoglycerate
PEP --> Pyruvate
B-form DNA - Answer -Watson-Crick model DNA. Deep, wide major groove.
Bacteriorhodopsin - Answer -Type III integral membrane protein with 7 connected helices.
Binding Cooperativity - Answer -When one subunit of hemoglobin changes from T to R-state the other
sites are more likely to change to R-state as well. Leads to sigmoidal graph.
Biotin Function - Answer -Prosthetic group that serves as a CO2 carrier to separate active sites on an
enzyme
Biotin Structure - Answer -
BPG (2,3-bisphosphoglycerate) - Answer -Greatly reduces hemoglobin's affinity for O2 by binding
allosterically. Stabilizes T-state. Transfer of O2 can improve because increased delivery in tissues can
outweigh decreased binding in the lungs.
Bypass Reactions in Gluconeogenesis - Answer -Steps 1,3, and 10 must be bypassed.
C4 Plants - Answer -Fix CO2 into PEP to form oxaloacetate (via PEP carboxykinase) that is then converted
to malate that carries CO2 to rubisco. Bypasses O2 binding.
CAM plants - Answer -Fix CO2 into PEP to form oxaloacetate (via PEP carboxykinase) that is converted to
malate at night and stored until the day time.
cAMP - Answer -Secondary messenger in GPCR signalling. Formed from ATP by adenylyl cyclase.
Activates PKA (protein kinase A).
Cardiolipin - Answer -"Lipid staple" that ties two proteins (or complexes) together in a membrane.
Formed from two phosphoglycerols.
Cellulose - Answer -Comes from plants. Poly D-glucose. Formed from ß-1,4-linkage. Form sheets due to
equatorial -OH groups that H-bond with other chains.
,Chargaff's Rule - Answer -Ratio of A:T and G:C are always equal or close to 1
Chitin - Answer -Homopolymer of N-acetyl-ß-D-glucosamine. Have ß-1,4-linkages. Found in lobsters,
squid beaks, beetle shells, etc.
Cholesterol Synthesis - Answer -Synthesized from 15 acetyl-CoA through a number of intermediates.
Chymotripsin - Answer -Cleaves proteins on C-terminal endof Phe, Trp, and Tyr
Circular Dichroism - Answer -Uses UV light to measure 2° structure. Can be used to measure
destabilization.
CO2 binding in Hemoglobin - Answer -Forms carbonic acid that shifts hemoglobin to T-state. O2 binding
affinity decreases. Used in the peripheral tissues.
CO2 Producing Steps of the Citric Acid Cycle - Answer -Steps 3 and 4
Isocitrate --> α-ketoglutarate
α-ketoglutarate --> Succinyl-CoA
Collagen - Answer -Repeating sequence of Gly-X-Pro. 3 stranded "coiled coil". Contains gly core.
Competitive Inhibition Graph - Answer -Slope changes by factor of α. Slope becomes αKm/Vmax.
X-intercept becomes 1/αKm
Y-intercept does not change.
Vmax does not change.
Complex I in the ETC - Answer -Accepts two electrons from NADH via an FMN cofactor. Transfers 4H+ to
Pside and 2H+ to Q
Complex II in the ETC - Answer -Succinate dehydrogenase. Accepts two electrons electrons from
succinate via an FAD group. Q --> QH2
Complex III in the ETC - Answer -Transfers two electrons from QH2 to cytochrome c via the Q-cycle.
Transfers 4H+ to Pside.
Complex IV in the ETC - Answer -Transfers electrons from cytochrome c to O2. Four electrons are used to
reduce on O2 into two H2O molecules. Transfers 4H+ to Pside
Cooperative Protein Folding - Answer -Folding transition is sharp. More reversible.
Cost of FAS in Eukaryotes - Answer -3 ATP's per 2 carbon unit added.
Cost of Gluconeogenesis - Answer -4 ATP, 2 GTP, and 2 NADH
, Different Steps in the Glyoxylate Cycle - Answer -Isocitrate --> Glyoxylate (+ succinate)
Uses isocitrate lyase
Glyoxylate (+ acetyl-coA) --> Malate
Uses malate synthase
Dihydrolipoyl Transacetylase - Answer -E2 domain of the PDH complex. Catalyzes formation of Acetyl-
CoA. Has oxidized, acyl, and reduced lipoyllysine.
Dihydrolipyl Dehydrogenase - Answer -E3 domain of the PDH complex. Catalyzes regeneration of the
lipoyllysine using FAD --> FADH2
Disulfide-bonds - Answer -Bonds between two -SH groups that form between 2° and 3° structure.
DNA Base-paring - Answer -G-C base pairs have 3 H-bonds
A-T base pairs have 2 H-bonds
DNA Double-Helix - Answer -Opposite strand direction. 3.4Å distance between complementary bases.
36Å for one complete turn.
DNA UV Absorbtion - Answer -Absorbs UV light at 260nm.
DTT (dithiothreitol) - Answer -Reduces disulfide bonds.
Energy Consumption of the Calvin Cycle - Answer -9 ATP molecules and 6 NADPH molecules for every 3
CO2 molecules that are fixated.
Enzyme Km and Substrate Concentration - Answer -Most enzymes have a Km that is near the
concentration of the substrate.
ETC (Electron Transport Chain) - Answer -Consists of 4 functional protein complexes.
Ethanol Fermentation - Answer -Pyruvate --> Acetalaldehyde --> Ethanol
Uses pyruvate decarboxylase (TPP) and alcohol dehydrogenase.
NADH --> CO2(TPP) + NAD+
F0 Domain of Mitochondrial ATP Synthase - Answer -Causes rotation of γ-subunit via a half channel and
H+ gradient
F1 Domain of Mitochondrial ATP Synthase - Answer -Hexamer of 3 αß dimers. Catalyze ADP + Pi --> ATP
via binding-change model
