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23 Cards in this Set
- Front
- Back
- 3rd side (hint)
What is metabolism?
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The overall process through which living systems acquire and utilize the free energy they need to carry out their various functions but coupling exergonic reactions of nutrient oxidation to the endergonic processes required to maintain the living state.
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Catabolism
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involved in degradation;
complex metabolites are exergonically broken down to simpler products chemical oxidation and formation of reduced cofactors of NADH, NADPH, and FADH2 |
Convergence of Pathways
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Anabolism
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involved in biosynthesis
reduction and formation of oxidized cofactors NAD+, NADP+, and FAD Requirement for energy input and use of ATP |
Divergence of pathways
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What are autotrophs?
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They can synthesize all their cellular constituents from simple molecules such as H20, CO2, NH3, and H2S.
Need an energy source--usually solar energy |
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What are heterotrophs?
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obtain energy through the oxidation of organic compounds (products of autotrophs); and hence are ultimately dependent on autotrophs from these substances
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What are aerobes and anaerobes?
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Two types of heterotrophs
Aerobes live in air and use molecular oxygen for metabolic reactions whereas anaerobes do no require oxygen for surviaval |
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Metabolic Processes in Heterotrophic Cells
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Route A: Organic compounds from environment are absorbed into organism such as fats, carbohydrates, and amino acids
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Route B: Special organic compounds that cannot be biosynthesized such as vitamins, essential amino acids, and fatty acids
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Stages of Metabolism
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Stage I: Cleavage of Polymeric Chain to monomeric units
Stage II: Formation of monomeric units into a common intermediate Stage III: common intermediate enters into pathway that produces the most amount of energy |
Common intermediate: Acetyl-CoA
used in degradative metabolism to produce CO2 and H2O by citric acid cycle, electron-transport chain, and oxidative phosphorylation |
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What are metabolic pathways?
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series of consecutive enzymatic reactions that produce specific products--the reactants, intermediates, and products are referred to as metabolites.
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Glycolysis pathway
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Linear
one substrate--->product |
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Biosynthesis of amino acids
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Linear
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Citric acid cycle
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subsrate reproduced, and product leaves each turn
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Fatty Acid degradation pathway
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lengthen/shortening of biomolecules
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Metabolic Pathways are irreversible
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If two metabolites are metabolically interconvertible, the pathway from the first to the second must be different from the pathway from the second to back to the first
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Principle characteristic of metabolic pathway (#1)
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Every metabolic pathway has a first committed step
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there is generally an irreversible (exergonic) reaction that commits the intermediate it produces to continue down the pathway
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All metabolic pathways are regulated
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pathways are controlled by regulating the enzymes that catalyze their first committed step. This is the most efficient way to exert control because it prevents the unnecessary synthesis of metabolites further along the pathway when they are not required
-controlled by the concentrations of substrate, products, intermediates, and enzymes |
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Pathways in eukaryotic cells occur in specific cellular locations
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the synthesis of metabolites in specific membrane bounded subcellular compartments makes their transport between these compartments a vital component of eukaryotic metabolism
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Oxidation-Reduction
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Enzyme: Oxidoreductases (dehyrogenases)
transfer of electrons |
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Group Transfer
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Enzyme: Transferases
Transfer of functional group from one molecule to another or within a single molecule |
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Hydrolytic Cleavage (Hydrolysis)
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Enzyme: Hydrolyases
cleavage of bonds by water (transfer of functional group to water) |
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Nonhydrolytic Cleavage
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Enzyme: Lyases
Splitting a molecule by nonhydrolytic processes |
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Isomerization and rearrangement
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Enzyme: Isomerases
Rearrangement of functional groups to form isomers |
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Bond Formation using energy from ATP
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Enzyme: Ligase
Formation of C-C and other bonds with energy from ATP |
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