ACS Exam 2022 Flashcards
1
Q
Henderson-Hasselbach Equation
A
pH = pKa + log ([A-] / [HA])
2
Q
FMOC Chemical Synthesis
A
Used in synthesis of a growing amino acid chain to a polystyrene bead. FMOC is used as a protecting group on the N-terminus.
3
Q
Salting Out (Purification)
A
Changes soluble protein to solid precipitate. Protein precipitates when the charges on the protein match the charges in the solution.
4
Q
Size-Exclusion Chromatography
A
Separates sample based on size with smaller molecules eluting later.
5
Q
Ion-Exchange Chromatography
A
Separates sample based on charge. CM attracts +, DEAE attracts -. May have repulsion effect on like charges. Salt or acid used to remove stuck proteins.
6
Q
Hydrophobic/Reverse Phase Chromatography
A
Beads are coated with a carbon chain. Hydrophobic proteins stick better. Elute with non-H-bonding solvent (acetonitrile).
7
Q
Affinity Chromatography
A
Attach a ligand that binds a protein to a bead. Elute with harsh chemicals or similar ligand.
8
Q
SDS-PAGE
A
Uses SDS. Gel is made from cross-linked polyacrylamide. Separates based off of mass with smaller molecules moving faster. Visualized with Coomassie blue.
9
Q
SDS
A
Sodium dodecyl sulfate. Unfolds proteins and gives them uniform negative charge.
10
Q
Isoelectric Focusing
A
Variation of gel electrophoresis where protein charge matters. Involves electrodes and pH gradient. Protein stops at their pI when neutral.
11
Q
FDNB (1-fluoro-2,3-dinitrobenzene)
A
FDNB reacts with the N-terminus of the protein to produce a 2,4-dinitrophenol derivative that labels the first residue. Can repeat hydrolysis to determine sequential amino acids.
12
Q
DTT (dithiothreitol)
A
Reduces disulfide bonds.
13
Q
Iodoacetate
A
Adds carboxymethyl group on free -SH groups. Blocks disulfide bonding.
14
Q
Homologs
A
Shares 25% identity with another gene
15
Q
Orthologs
A
Similar genes in different organisms
16
Q
Paralogs
A
Similar “paired” genes in the same organism
17
Q
Ramachandran Plot
A
Shows favorable phi-psi angle combinations. 3 main “wells” for α-helices, ß-sheets, and left-handed α-helices.
18
Q
Glycine Ramachandran Plot
A
Glycine can adopt more angles. (H’s for R-group).
19
Q
Proline Ramachandran Plot
A
Proline adopts fewer angles. Amino group is incorporated into a ring.
20
Q
α-helices
A
Ala is common, Gly & Pro are not very common. Side-chain interactions every 3 or 4 residues. Turns once every 3.6 residues. Distance between backbones is 5.4Å.
21
Q
Helix Dipole
A
Formed from added dipole moments of all hydrogen bonds in an α-helix. N-terminus is δ+ and C-terminus is δ-.
22
Q
ß-sheet
A
Either parallel or anti-parallel. Often twisted to increase strength.
23
Q
Anti-parallel ß-sheet
A
Alternating sheet directions (C & N-termini don’t line-up). Has straight H-bonds.
24
Q
Parallel ß-sheet
A
Same sheet directions (C & N-termini line up). Has angled H-bonds.
25
ß-turns
Tight u-turns with specific phi-psi angles. Must have gly at position 3. Proline may also be at ß-turn because it can have a cis-omega angle.
26
Loops
Not highly structured. Not necessary highly flexible, but can occasionally move. Very variable in sequence.
27
Circular Dichroism
Uses UV light to measure 2° structure. Can be used to measure destabilization.
28
Disulfide-bonds
Bonds between two -SH groups that form between 2° and 3° structure.
29
ß-mercaptoethanol
Breaks disulfide bonds.
30
α-keratin
formed from 2 α-helices twisted around each other. "Coiled coil". Cross-linked by disulfide bonds.
31
Collagen
Repeating sequence of Gly-X-Pro. 3 stranded "coiled coil". Contains gly core.
32
Myoglobin 4° Structure
Symmetric homodimer,
33
Hemoglobin 4° Structure
Tetramer. Dimer of dimers. α2ß2 tetramer.
34
α/ß Protein Folding
Less distinct areas of α and ß folding.
35
α+ß Protein Folding
Two distinct areas of α and ß folding.
36
Mechanism of Denaturants
Highly soluble, H-binding molecules. Stabilize protein backbone in water. Allows denatured state to be stabilized.
37
Temperature Denaturation of Protein
Midpoint of reaction is Tm.
38
Cooperative Protein Folding
Folding transition is sharp. More reversible.
39
Folding Funnel
Shows 3D version of 2D energy states. Lowest energy is stable protein. Rough funnel is less cooperative.
40
Protein-Protein Interfaces
Core and "fringe" of the interfaces. Core is more hydrophobic and is on the inside when interfaced. Fringe is more hydrophilic.
41
π-π Ring Stacking
Weird interaction where aromatic rings stack on each other in positive interaction.
42
σ-hole
Methyl group has area of diminished electron density in center; attracts electronegative groups
43
Fe Binding of O2
Fe2+ binds to O2 reversible. Fe3+ has an additional + charge and binds to O2 irreversibly. Fe3+ rusts in O2 rich environments.
44
Ka for Binding
Ka = [PL] / [P][L]
45
ϴ-value in Binding
ϴ = (bound / total)x100%
46
Kd for binding
Kd = [L] when 50% bound to protein.
47
High-Spin Fe
Electrons are "spread out" and result in larger atom.
48
Low-Spin Fe
Electrons are less "spread out" and are compacted by electron rich porphyrin ring.
49
T-State
Heme is in high-spin state. H2O is bound to heme.
50
R-State
Heme is in low-spin state. O2 is bound to heme.
51
O2 Binding Event
O2 binds to T-state and changes the heme to R-state. Causes a 0.4Å movement of the iron.
52
Hemoglobin Binding Curve
4 subunits present in hemoglobin that can be either T or R -state. Cooperative binding leads to a sigmoidal curve.
53
Binding Cooperativity
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.
54
Homotropic Regulation of Binding
Where a regulatory molecule is also the enzyme's substrate.
55
Heterotropic Regulation of Binding
Where an allosteric regulator is present that is not the enzyme's substrate.
56
Hill Plot
Turns sigmoid into straight lines. Slope = n (# of binding sites). Allows measurement of binding sites that are cooperative.
57
pH and Binding Affinity (Bohr Affect)
As [H+] increases, Histidine group in hemoglobin becomes more protonated and protein shifts to T-state. O2 binding affinity decreases.
58
CO2 binding in Hemoglobin
Forms carbonic acid that shifts hemoglobin to T-state. O2 binding affinity decreases. Used in the peripheral tissues.
59
BPG (2,3-bisphosphoglycerate)
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.
60
Michaelis-Menton Equation
V0 = (Vmax[S]) / (Km + [S])
61
Km in Michaelis-Menton
Km = [S] when V0 = 0.5(Vmax)
62
Lineweaver-Burke Graph
Slope = Km/Vmax
63
Lineweaver-Burke Equation
Found by taking the reciprocal of the Michaelis-Menton Equation.
64
Kcat
Rate-limiting step in any enzyme-catalyzed reaction at saturation. Known as the "turn-over number". Kcat = Vmax/Et
65
Chymotripsin
Cleaves proteins on C-terminal endof Phe, Trp, and Tyr
66
Competitive Inhibition Graph
Slope changes by factor of α. Slope becomes αKm/Vmax.
67
Uncompetitive Inhibition Graph
Does not change slope.
68
Mixed Inhibition Graph
Allosteric inhibitor that binds either E or ES.
69
Non-Competitive Inhibition Graph
Form of mixed inhibition where the pivot point is on the x-axis. Only happens when K1 is equal to K1'.
70
Ionophore
Hydrophobic molecule that binds to ions and carries them through cell membranes. Disrupts concentration gradients.
71
ΔGtransport Equation
ΔGtransport = RTln([S]out / [S]in) + ZFΔΨ
72
Pyranose vs. Furanose
Pyranose is a 6-membered ring.
73
Mutarotation
Conversion from α to ß forms of the sugar at the anomeric carbon.
74
Anomeric Carbon
Carbon that is cyclized. Always the same as the aldo or keto carbon in the linear form.
75
α vs. ß sugars
α form has -OR/OH group opposite from the -CH2OH group.
76
Starch
Found in plants. D-glucose polysaccharide. "Amylose chain". Unbranched. Has reducing and non-reducing end.
77
Amylose Chain
Has α-1,4-linkages that produce a coiled helix similar to an α-helix. Has a reducing and non-reducing end.
78
Amylopectin
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.
79
Reducing Sugar
Free aldehydes can reduce FeIII or CuIII. Aldehyde end is the "reducing" end.
80
Glycogen
Found in animals. Branched every 8-12 residues and compact. Used as storage of saccharides in animals.
81
Cellulose
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.
82
Chitin
Homopolymer of N-acetyl-ß-D-glucosamine. Have ß-1,4-linkages. Found in lobsters, squid beaks, beetle shells, etc.
83
Glycoproteins
Carbohydrates attached to a protein. Common outside of the cell. Attached at Ser, Thr, or Asn residues.
84
Membrane Translayer Flip-Flop
Typically slow, but can be sped up with Flippase, Floppase, or Scramblase.
85
Membrance Fluidity
Membrane must be fluid. Cis fats increase fluidity, trans fats decrease fluidity.
86
Type I Integral Membrane Protein
Membrane protein with C-terminus inside and N-terminus outside
87
Type II Integral Membrane Protein
Membrane protein with N-terminus inside and C-terminus outside
88
Type III Integral Membrane Protein
Membrane protein that contains connected protein helices
89
Type IV Integral Membrane Protein
Membrane protein that contains unconnected protein helices
90
Bacteriorhodopsin
Type III integral membrane protein with 7 connected helices.
91
ß-Barrel Membrane Protein
Can act as a large door. Whole proteins can fit inside.
92
α-hemolysin
Secreted as a monomer. Assembles to punch holes in membranes.
93
Cardiolipin
Lipid staple that ties two proteins (or complexes) together in a membrane. Formed from two phosphoglycerols.
94
Hydrolysis of Nucleotides
Base hydrolyzes RNA, but not DNA. DNA is stable in base because of 2' deoxy position.
95
Chargaff's Rule
Ratio of A:T and G:C are always equal or close to 1
96
DNA Double-Helix
Opposite strand direction. 3.4Å distance between complementary bases. 36Å for one complete turn.
97
A-form DNA
Condensed form of DNA. Deeper major groove and shallower minor groove.
98
B-form DNA
Watson-Crick model DNA. Deep, wide major groove.
99
Z-form DNA
Left-handed helical form of DNA
100
Inverted Repeat in DNA
Found in double-strands.
101
Mirror Repeat in DNA/RNA
Found in single-strands.
102
DNA UV Absorbtion
Absorbs UV light at 260nm.
103
Restriction Enzyme
Cuts DNA at specific restriction sites.
104
DNA Base-paring
G-C base pairs have 3 H-bonds
105
GPCR (G-protein coupled receptor)
α-helical integral membrane proteins. Is a αßɣ heterotrimer.
106
ß-adrenergic receptor
Prototype for all GPCR's. Bind adrenaline/epinephrine to stimulate breakdown of glycogen.
107
Step 1 of Epinephrine Signal Transduction
Epinephrine binds to its specific receptor
108
Step 2 of Epinephrine Signal Transduction
Hormone complex causes GDP bound to α-subunit to be replaced by GTP, activating α-subunit
109
Step 3 of Epinephrine Signal Transduction
Activated α-subunit separates from ßɣ-complex and moves to adenylyl cyclase, activating it.
110
Step 4 of Epinephrine Signal Transduction
Adenylyl cyclase catalyzes the formation of cAMP from ATP
111
Step 5 of Epinephrine Signal Transduction
cAMP phosphorylates PKA, activating it
112
Step 6 of Epinephrine Signal Transduction
Phosphorylated PKA causes an enzyme cascade causing response to epinephrine
113
Step 7 of Epinephrine Signal Transduction
cAMP is degraded, reversing activation of PKA. α-subunit hydrolyzes GTP to GDP and becomes inactivated.
114
cAMP
Secondary messenger in GPCR signalling. Formed from ATP by adenylyl cyclase. Activates PKA (protein kinase A).
115
AKAP
Anchoring protein that binds to PKA, GPCR, and adenylyl cyclase.
116
GAPs (GTPase activator proteins)
Increase activity of GTPase activity in α-subunit of GPCR.
117
ßARK and ßarr
Used in desensitization. ßARK phosphorylates receptors and ßarr draws receptor into the cell via endocytosis
118
RTKs (Receptor Tyrosine Kinases)
Have tyrosine kinase activity that phosphorylates a tyrosine residue in target proteins
119
INSR (Insulin Receptor Protein)
Form of RTK. Catalytic domains undergo auto-phosphorylation.
120
INSR signalling cascade
INSR phosphorlates IRS-1 that causes a kinase cascade.
121
INSR cross-talk
INSR causes a kinase cascade that alters gene expression and phosphorlates ß-adrenergic receptor causing its endocytosis.
122
FADH2
Single-electron transfer
123
FMN
Single electron transfer.
124
Step 1 of Glycolysis
Glucose --> Glucose 6-phosphate.
125
Step 2 of Glycolysis
Glucose 6-phosphate <--> Fructose 6-phosphate
126
Step 3 of Glycolysis
Fructose 6-phosphate --> Fructose 1,6-bisphosphate
127
First Committed Step of Glycolysis
Step 3 of Glycolysis.
128
Step 4 of Glycolysis
Fructose 1,6-bisphosphate <--> dihydroxyacetone + glyceraldehyde 3-phosphate.
129
Step 5 of Glycolysis
Dihydroxyacetonephosphate <--> glyceraldehyde 3-phosphate
130
Step 6 of Glycolysis
Glyceraldehyde 3-Phosphate + Pi <--> 1,3-biphosphoglycerate.
131
First Energy Yielding Step of Glycolysis
Step 6 of Glycolysis.
132
Step 7 of Glycolysis
1,3-bisphosphoglycerate + ADP <--> 3-phosphoglycerate + ATP
133
First ATP Yielding Step of Glycolysis
Step 7 of Glycolysis.
134
Step 8 of Glycolysis
3-phosphoglycerate <--> 2-phosphoglycerate
135
Step 9 of Glycolysis
2-phosphoglycerate <--> Phosphoenolpyruvate (PEP)
136
Step 10 of Glycolysis
PEP + ADP --> Pyruvate + ATP
137
ATP Consuming Steps of Glycolysis
Step 1 and 3.
138
ATP Producing Steps of Glycolysis
Steps 7 and 10.
139
NADH Producing Step of Glycolysis
Step 6
140
Total Energy Produced by Glycolysis
2NADH + 4 ATP
141
Lactic Acid Fermentation
Pyruvate --> L-Lactate
142
Ethanol Fermentation
Pyruvate --> Acetalaldehyde --> Ethanol
143
TPP Cofactor
Common acetaldehyde carrier. Used in pyruvate decarboxylase, pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, and transketolase
144
Bypass Reactions in Gluconeogenesis
Steps 1,3, and 10 must be bypassed.
145
Gluconeogenic Bypass of Step 10
Bicarbonate + Pyruvate --> Oxaloacetate
146
Gluconeogenic Bypass of Step 3
Fructose 1,6-bisphosphate + H2O --> Fructose 6-phosphate + Pi
147
Gluconeogenic Bypass of Step 1
Glucose 6-phosphate + H2O --> Glucose + Pi
148
Cost of Gluconeogenesis
4 ATP, 2 GTP, and 2 NADH
149
Oxidative Pentose Phosphate Pathway
Uses glucose 6-phosphate to produce 2 NADPH and ribose 5-phosphate used for biosynthesis
150
Non-Oxidative Pentose Phosphate Pathway
Regenerates glucose 6-phosphate from ribose 5-phosphate.
151
Transketolase
Transfers a two-carbon keto group
152
Transaldolase
Transfers a three-carbon aldo group
153
Enzyme Km and Substrate Concentration
Most enzymes have a Km that is near the concentration of the substrate.
154
Fructose 2,6-bisphosphate
Not a glycolytic intermediate. Interconverts between fructose 2,6-bisphosphate and fructose 6-phosphate using PFK-2 and FBPase-2
155
Regulation with fructose 2,6-bisphosphate
Activates PFK-1 encouraging glycolysis. Inhibits FBPase-1 discouraging gluconeogenesis
156
Regulation of Pyruvate Kinase
Inhibited by ATP, Acetyl-Coa, Alanine, long-chain FA's.
157
PDH (Pyruvate Dehydrogenase Complex)
Large complex that converts pyruvate + Coa --> Acetyl-Coa + CO2
158
Pyruvate Dehydrogenase
E1 domain of the PDH complex. Contains TPP cofactor. Releases CO2.
159
Dihydrolipoyl Transacetylase
E2 domain of the PDH complex. Catalyzes formation of Acetyl-CoA. Has oxidized, acyl, and reduced lipoyllysine.
160
Dihydrolipyl Dehydrogenase
E3 domain of the PDH complex. Catalyzes regeneration of the lipoyllysine using FAD --> FADH2
161
Step 1 of the Citric Acid Cycle
Acetyl-CoA + Oxaloacetate --> Citrate
162
Rate-limiting Step of the Citric Acid Cycle
Step 1
163
Step 2 of the Citric Acid Cycle
Citrate <--> Isocitrate
164
Step 3 of the Citric Acid Cycle
Isocitrate --> α-ketoglutarate
165
Step 4 of the Citric Acid Cycle
α-ketoglutarate --> succinyl-CoA
166
Step 5 of the Citric Acid Cycle
Succinyl-CoA <--> Succinate
167
Step 6 of the Citric Acid Cycle
Succinate <--> Fumarate
168
Step 7 of the Citric Acid Cycle
Fumarate <--> L-Malate
169
Step 8 of the Citric Acid Cycle
L-Malate <--> Oxaloacetate
170
Net Energy Gain of the Citric Acid Cycle
3 NADH, FADH2, and GTP
171
NADH Producing Steps of the Citric Acid Cycle
Steps 3, 4, and 8.
172
FADH2 Producing Steps of the Citric Acid Cycle
Step 6
173
GTP/ATP Producing Steps of the Citric Acid Cycle
Step 5
174
CO2 Producing Steps of the Citric Acid Cycle
Steps 3 and 4
175
Biotin Function
Prosthetic group that serves as a CO2 carrier to separate active sites on an enzyme
176
Regulation of the Citric Acid Cycle
Regulation occurs at Steps 1, 2, 4, and 5.
177
Glyoxylate Cycle
Found in plants. Produces succinate from 2 acetyl-CoA. Allows oxaloacetate in the CAC to be used in gluconeogenesis. Uses 3 steps from the CAC.
178
Different Steps in the Glyoxylate Cycle
Isocitrate --> Glyoxylate (+ succinate)
179
Step 1 of ß-oxidation
Fatty acyl-CoA --> trans-Δ2-enoyl-CoA
180
Step 2 of ß-oxidation
trans-Δ2-enoyl-CoA (+ H2O) --> L-ß-hydroxy-acyl-CoA
181
TFP (Trifunctional Protein)
Protein complex that catalyzes the last three reactions of ß-oxidation.
182
Step 3 of ß-oxidation
L-ß-hydroxy-acyl-CoA --> ß-ketoacyl-CoA
183
Oxidation of Odd-numbered FA's
Results in propionyl-CoA formation. Propionyl-CoA can be converted to succinyl-CoA and used in the CAC
184
Step 4 of ß-oxidation
ß-ketoacyl-CoA (+ CoA) --> Fatty acyl-Coa (shorter)
185
ß-oxidation in plants
Electrons are passed directly to molecular oxygen releasing heat and H2O2 instead of the respiratory chain.
186
ω-oxidation
Similar to ß-oxidation but occurs simultaneously on both ends of the molecule.
187
α-oxidation
Form of oxidation of branched FA's. Produced propionyl-CoA that must be converted to succinyl-CoA for use in the CAC
188
Ketone bodies
Consists of Acetoacetate, Acetone, and D-ß-hydroxybutryate.
189
Zymogen
An inactive precursor of an enzyme, activated by various methods (acid hydrolysis, cleavage by another enzyme, etc.)
190
Amidotransferase
Uses a PLP group to transfer amino group from an amino acid to α-ketoglutarate to form L-glutamate and an α-ketoglutarate.
191
Ammonia (NH4+) Transportation
L-glutamate is converted to L-glutamine via glutamine synthetase.
192
Glucose-Alanine Cycle
Pyruvate can be converted into Alanine via alanine aminotransferase (PLP). Adds a NH4+ group from glutamate to pyruvate. Alanine can travel to the liver and be reconverted back into pyruvate needed for gluconeogenesis.
193
Production of carbamoyl-phosphate
NH4+ --> Carbamoyl Phosphate
194
Step 1 of the Urea Cycle
Ornithine (+ carbamoyl phosphate) --> citrulline
195
Step 2 of the Urea Cycle
Citrulline --> Arginosuccinate
196
Step 3 of the Urea Cycle
Arginosuccinate --> Argininine
197
Step 4 of the Urea Cycle
Arginine --> Ornithine
198
N-acetylglutamate
Upregulates the production of carbamoyl phosphate and the urea cycle. Formed from acetyl-CoA and glutamate.
199
PCR (Protein Chain Reaction)
Process by which DNA is replicated. Has melting step, annealing step, replication step.
200
pKa of Arginine R-group
12.5
201
pKa of Aspartate R-group
3.9
202
pKa of Cysteine R-group
8
203
pKa of Glutamate R-group
4
204
pKa of Histidine R-group
6.1
205
pKa of Lysine R-group
10.5
206
pKa of Tyrosne R-group
10
207
Q (Ubiquinone/Coenzyme Q) Function
Lipid soluble electron carrier. Carries 2 electrons with 2 H+.
208
ETC (Electron Transport Chain)
Consists of 4 functional protein complexes.
209
Complex I in the ETC
Accepts two electrons from NADH via an FMN cofactor. Transfers 4H+ to Pside and 2H+ to Q
210
Complex II in the ETC
Succinate dehydrogenase. Accepts two electrons electrons from succinate via an FAD group. Q --> QH2
211
Complex III in the ETC
Transfers two electrons from QH2 to cytochrome c via the Q-cycle. Transfers 4H+ to Pside.
212
Complex IV in the ETC
Transfers electrons from cytochrome c to O2. Four electrons are used to reduce on O2 into two H2O molecules. Transfers 4H+ to Pside
213
Mitochondrial ATP Synthase
Consists of F1 and F0 domains
214
F1 Domain of Mitochondrial ATP Synthase
Hexamer of 3 αß dimers. Catalyze ADP + Pi --> ATP via binding-change model
215
F0 Domain of Mitochondrial ATP Synthase
Causes rotation of γ-subunit via a half channel and H+ gradient
216
Malate-Aspartate Shuttle
Used to maintain gradient of NADH inside of the mitochondria. Involves transport of malate or aspartate; aspartate aminotransferase; and malate dehydrogenase.
217
RuBisCo (Ribulose 1,5-bisphosphate carboxylase/oxygenase)
Incorporates CO2 into ribulose 1,5-bisphosphate and cleaves the 6C intermediate into 2 3-phosphoglycerate.
218
Stage 1 of the Calvin Cycle
3 ribulose 1-5-bisphosphate + 3 CO2 --> 6 3-phosphoglycerate.
219
Mg2+ in Rubisco
Stabilizes negative charge in intermediate and held by Glu, Asp, and carbamoylated Lysine residue
220
Rubisco Activase
Triggers removal of ribulose 1,5-bisphosphate or 2-carboxyaarabinitol 1-phosphate so Lys can be carbamoylated.
221
2-carboxyarabinitol 1-phosphate
inhibits carbamoylated rubisco. Synthesized in the dark and is broken down by rubisco activase or light.
222
Stage 2 of the Calvin Cycle
3-phosphoglycerate --> glyceraldehyde 3-phosphate
223
Stage 3 of the Calvin Cycle
Glyceraldehyde 3-phosphate --> Ribulose 1,5-bisphosphate
224
Energy Consumption of the Calvin Cycle
9 ATP molecules and 6 NADPH molecules for every 3 CO2 molecules that are fixated.
225
Pi-Triose Phosphate Anti-porter
Maintains Pi balance in cytosol/chloroplast due to G3P export to the cytosol.
226
Oxygenase Activity in Rubisco
O2 competes with CO2 and reacts to form 2-phosphoglycerate
227
Glycolate Cycle
Process of converting 2-phosphoglycerate to 3-phosphoglycerate in chloroplast, peroxisome, and mitochondria.
228
C4 Plants
Fix CO2 into PEP to form oxaloacetate (via PEP carboxykinase) that is then converted to malate that carries CO2 to rubisco. Bypasses O2 binding.
229
CAM plants
Fix CO2 into PEP to form oxaloacetate (via PEP carboxykinase) that is converted to malate at night and stored until the day time.
230
Malonyl-CoA
Formed from Acetyl-CoA and HCO3 via the Acetyl-CoA carboxylase (ACC). Serves as a regulator of FA catabolism and precursor in FA synthesis.
231
ACC (acetyl-CoA carboxylase) Regulation
Inhibited by PKA in glucagon chain and activated by pjhosphatase in INSR chain.
232
FAS (Fatty-acid Synthetase)
Catalyzes condensation, reduction, dehydration, and reduction of growing fatty acid chain. Requires activation by acetyl-CoA or malonyl-CoA
233
Additional Cost of FAS in Eukaryotes
Acetyl-CoA for lipid synthesis is made in mitochondria and must be transferred into the cytosol via citrate transporter. Costs 2 ATP.
234
Cost of FAS in Eukaryotes
3 ATP's per 2 carbon unit added.
235
Phosphatidic Acid
Common precursor to TAGs and phospholipids. Consists of a glycerol 3-phosphate with two acyl groups that are attached via acyl transferases.
236
TAGs (Triacylglycerols)
Made from phosphatidic acid by removing phosphate with phosphatase and adding an acyl group with acyl transferase.
237
Cholesterol Synthesis
Synthesized from 15 acetyl-CoA through a number of intermediates.
238
HMG-CoA Reductase
Enzyme that converts ß-hydroxy-ß-methyl glutaryl-CoA to mevalonate in cholesterol metabolism.
239
Regulation of HMG-CoA Reductase
Inhibited by AMPK (AMP dependent kinase), glucagon, and oxysterol.
240
Ribonucleotide Reductase
Contains two types of allosteric regulatory sites for activity and specificity. Converts ribonucleotides to deoxyribonucleotides.
241
Nitrogenase Complex
Uses ATP hydrolysis and ATP binding to overcome activation energy. Has a FeMo cofactor. Is an α2ß2 homodimer. Fixes N2 into NH4+
242
Anaerobic Ammonia Oxidation (Anammox)
Ability of some bacteria to oxidize NH4+ and NO2- into N2. "Short-circuits" the nitrogen cycle.
243
Glutamine Synthetase Regulation in Nitrogen Metabolism
Catalyzes conversion of glutamate to glutamine. Inhibited by Gly, Ala, and endpoints of glutamine metabolism. Additive effectors.
244
Glutamine amidotransferase
Enzyme that catalyzes the transfer of the amino group from glutamine to an amino group acceptor. Forms glutamate. Used in biosynthetic pathways.
