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36 Cards in this Set
- Front
- Back
1st law of thermodynamics
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Energy cannot be created or destroyed
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2nd law of thermodynamics
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Energy transformation is not 100% efficient, and usable energy is lost, while entropy increases
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Gibbs Free Energy Equation
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∆G=∆H-T∆S
+∆G = endergonic, anabolism -∆G = exergonic, catabolism |
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Gibbs free energy needed to reach equilibrium
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∆G = ∆G˚ +RT ln ([C][D]/[A][B])
∆G˚ = ∆G when reactants and products in 1 molar quantities |
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Equilibrium Constant
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Keq = ([C][D]/[A][B])
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∆G'˚ and K'eq
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∆G˚ and Keq at pH = 7 and T = 37˚C
K'eq > 1; ∆G'˚< 0 K'eq = 1; ∆G'˚= 0 K'eq < 1; ∆G'˚> 0 |
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5 Characteristics of Metabolism
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1. Irreversible
2. Independent Catabolic and Anabolic pathways 3. First committed step 4. Regulated (usually through enzymes) 5. Specific cellular locations |
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5 reactions in Metabolism
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1. Make or break carbon bonds
2. Internal rearrangement, isomerization, elimination 3. Free radical reaction 4. Group transfer reaction 5. Oxidation-Reduction reaction |
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ATP Hydrolysis
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- H2O hydrolyzes ATP
- Phosphate group stabilized by resonance - ATP and ADP stabilized by Mg2+ |
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Human's Daily ATP
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- Take in 11,700 kJ of food
- 50% efficiency, 5860 kJ to ATP - 50 kJ/ATP = 117 moles ATP/day - 50 g of ATP in body; so each one recycled 1300x |
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ATP Generation Mechanisms
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1. Substrate-Level Phosphorylation
2. Oxidative Phosphorylation 3. Photophosphorylation |
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Substrate-Level Phosphorylation
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Transfer of high energy PO4- group from compound to ADP
- Different Energy per compound - ex: PEP, Creatine Phosphate |
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Oxidative-Phosphorylation
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ATP created from proton gradient created by transfer of electrons in an electron transport chain
- Triggered by compounds |
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Photophosphorylation
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ATP created from proton gradient created by transfer of electrons in an electron transport chain
- Triggered by sunlight |
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Carbohydrates/Saccharides
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- Formula = (CH2O)n
- Act as Structural Elements or Energy Sources - Can exist in many "isomeric forms" |
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Monosaccharide
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- Simple sugars with 3-7 Carbon Atoms
- Many Types: - Aldose: Contains aldehyde group - Ketose: Contains ketose group |
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Monosaccharide Cyclization
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- Occurs in pentoses and hexoses
- Carbonyl group -> Anomeric Carbon - Carbonyl Oxygen -> hydroxyl group (determines whether the sugar is alpha or beta) - Different side as CH2OH? alpha - Same side? beta |
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Oligosaccharides
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Typically 2-10 molecules
Bound by glycosidic bonds (dehydration) Usually found covalently bound to proteins or lipids on cell surface to act as recognition signals |
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Polysaccharides
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10-infinite number of molecules
Bound through dehydration (glycosidic bonds) Different locations of binding lead to differences in starch, glycogen, or cellulose - alpha cyclic sugars makes alpha glycosidic linkage - beta sugar makes beta linkage |
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Molecular Binding of Cellulose vs Starch vs Glycogen
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Cellulose -> B 1,4 linkages (linear)
Starch and Glycogen -> A 1,4 linkages - A 1,6 linkages allow branching - C1 = Anomeric carbon - Glycogen is higher branched than starch |
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3 Great Characteristics of Glucose
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1. complete oxidation -> ∆G'˚ = -2,840 kJ/mole
2. Can be stored as large quantities of hexose units, controlling blood sugar levels and allowing easy transition to ATP 3. Versatile Precursor to many biosynthetic reactions |
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4 major fates of glucose
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1. Synthesis of complex polysaccharides (for ECM and cell wall)
2. Storage as glucose polymers (for storage) 3. Oxidation to ribose 5-phosphate (via pentose phosphate pathway, for DNA) 4. Oxidation to pyruvate via glycolysis (for ATP) |
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Two Glycolitic Stages
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1. Preparatory Phase
2. Energy Conserving Stage (payout) - Takes 10 Reactions - Process turns Glucose -> (2) 3 carbon pyruvic acid + ATP + NADH |
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Glytolitic Stage 1: Preparatory Phase
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2 ATP's are invested
Glucose -> Fructose 1,6 biphosphate (F-1,6-BP) then F-1,6-BP -> (2) triose glcyeraldehyde 3-phosphate (GAP) |
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Glytolitic Stage 2: Energy Conserving Stage
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(2) GAP -> (2) Pyruvate + 4 ATP + 2NADH
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Feeder Pathways from Storage
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Starch or Glycogen feed into glycolysis 2 steps
1. Phospholytic cleavage of terminal glucose --> glucose 1-phosphate 2. Phosphoglucomutase converts glucose 1-phosphate into glucose 6-phosphate |
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Feeder Pathways from ingestion
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Ingested polysaccharides broken down by intestinal hydrolytic enzymes -> monosaccharides
- Leads to variety of D-Hexoses; which can be phosphorylated into G6P, F6P, or F1P - Galactose 1P and Glucose 1P require nucleotide derived UDP |
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3 Pyruvate Fates
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1. 2 Ethanol + CO2 (fermentation in yeast)
- Makes alchohol 2. 2 Acetyl CoA (aerobic) 3. Lactate (anerobic) - cheese/yogurt |
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Regeneration of NADH
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Glycolytic oxidation of glyceraldehyde uses NAD+ as electron acceptor. O2 takes this electron back to regenerate NAD+; but in anaerobic conditions, an organic molecule (i.e. lactate,ethanol) accepts this electron
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Metabolic Regulation Tactics
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1. Altering enzyme activity
2. Using equilibrium and mass action 3. Have tissue specific isozymes of enzymes (same enzyme, different tissue, different rate) 4. Responding to energy (ATP/ADP) ratios (most enzymes need full ATP saturation) |
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AMP-Activated ATP Kinase (AMPK)
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When [ATP]/[AMP] decreases, triggers AMPK to increase ATP.
- Activated by low ratio, exercise, SNS, or hormones - When active, phosphorylates proteins and shifts metabolism away from energy (ATP) consumption - Ex: Makes brain hungry, increases fatty acid oxidation |
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AMP Production
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AMP produced by:
1. ATP hydrolyzed to ADP 2. 2 ADP converted to 1 ATP and 1 AMP |
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4 ways of regulating glycolysis and glyconeogenesis
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1. Allosteric Activation/Inhibition (intracellular)
2. Reversible Phosphorylation 3. Regulating Expression of Genes (via T-factors) 4. Signal Transduction Events |
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Allosteric Regulation in PFK and FBPase
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PFK = ATP + F6P -> ADP + F1,6P -> Glycolysis
FBPase = F1,6P + H2O -> F6P + Pi -> Gluconeogenesis F26BP activates PFK, inhibits FBPase - Contains Kinase group and Phosphotase group - F26BP increases glycolysis Insulin activates PFK, glucagon activates FBPase |
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Reversible Phosphorylation of Pyruvate Kinase
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Phosphorylated P-Kinase is less active
- Becomes phosphorylated in presence of ATP |
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Insulin Gene Regulation
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Insulin attaches to a receptor that goes on to downregulate genes for gluconeogenic enzymes
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