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17 Cards in this Set
- Front
- Back
Exergonic Reactions
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-Release energy
-Reactants contain more energy than products in exergonic reactions |
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ATP is an example of activation energy
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All chemical reactions require an initial energy input (activation energy) to get started
--Molecules need to be moving with sufficient collision speed --The electrons of an atom repel other atoms and inhibit bond formation |
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Endergonic Reactions
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-Require an input of energy
-Products contain more energy than reactants in endergonic reactions |
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Energy-carrier molecules
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-Are used to transfer the energy within cells
-Act as intermediates to carry energy between exergonic and endergonic reactions -Only used within cells because they are unstable |
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Adenosine triphosphate (ATP)
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-The most common energy carrying molecule
-ATP is composed of an adenosine molecule and three phosphates -Energy is stored in the high-energy bond extending to the last phosphate -Heat is given off when ATP breaks into ADP (adenosine diphosphate) and P (phosphate) |
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2 types of fermentation
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alcohol fermentation and lactic fermentation
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Electron carriers
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transport high-energy electrons
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Metabolism
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The sum of all the chemical reactions inside a cell
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Many cellular reactions are linked through
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Metabolic pathways
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Metabolic pathways proceed smoothly for three reasons:
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-Endergonic reactions are coupled with exergonic reactions
-Energy-carrier molecules capture energy and transfer it between endergonic and exergonic reactions -Chemical reactions are regulated through protein enzymes |
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We need enzymes to
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act by lowering the activation needed for the reaction to occur, to make it easier to occur/speed it up
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Catalysts
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speed up spontaneous reactions by reducing activation energy
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Enxymes aka biological catalysts
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-Orient, distort, and reconfigure molecules in the process of lowering activation energy
--Different from non-biological catalysts because: -Enzymes are very specific for the molecules they catalyze -Enzyme activity is often enhanced or suppressed by their reactants or products |
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Some enzymes require helper ______ molecules to function (ex. certain B vitamins)
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coenzyme
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3 steps of enzyme catalysis
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-Substrates enter the active site in a specific orientation
-Upon binding, the substrates and enzyme change shape to promote a reaction -Products of the reaction leave the active site, leaving the enzyme ready for another catalysis |
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Enzymes have a pocket called an
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-Active site
-Reactants (substrates) bind to the active site |
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How metabolic pathways are controlled (more than one way)
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Cells regulate metabolism
-Control of enzyme synthesis regulates availability -Some enzymes are inactive when synthesized and must be “turned on” to be active |