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69 Cards in this Set
- Front
- Back
Totality of an organism's chemical processes. |
Metabolism
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Metabolic pathways which release energy by breaking down complex molecules to simpler compounds.
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Catabolic pathways
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Metabolic pathways which consume energy to build complicated molecules from simpler ones.
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Anabolic pathways
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the capacity to do work - to move matter against opposing forces.
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Energy
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Energy in the process of doing work (energy of motion).
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Kinetic energy
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Energy that matter possesses because of its location or arrangement (energy of position).
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Potential energy
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Study of energy transformations
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Thermodynamics
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Collection of matter under study which is isolated from its surroundings
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Closed system
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System in which energy can be transferred between the system and its surroundings.
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Open system
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Energy can be transferred and transformed, but it cannot be created or destroyed (energy of the universe is constant).
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First Law of Thermodynamics
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Every energy transfer or transformation makes the universe more disordered (every process increases the entropy of the universe).
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Second Law of Thermodynamics
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Quantitative measure of disorder that is proportional to randomness (designated by the letter S).
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Entropy
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Those reactions that can occur without outside help.
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Spontaneous processes
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Those reactions that can only occur if energy is added to a system.
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Nonspontaneous processes
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Portion of a system's energy available to do work; is the difference between the total energy (enthalpy) and the energy not available for doing work (TS).
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Free energy (G)
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Formula for free energy
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G = H - TS
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Formula for free energy change
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ΔG = ΔH - TΔS
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In the formula for free energy change, what is ∆G?
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change in Free energy
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In the formula for free energy change, what is ∆H?
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change in Enthalpy (total energy)
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In the formula for free energy change, what is ∆S?
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change in Entropy
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In the formula for free energy change, what is T?
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Temperature in Kelvin
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A reaction that proceeds with a net loss of free energy.
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Exergonic reaction
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An ________reaction is one that releases free energy to its surroundings.
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exergonic
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Δ G of an exergonic reaction is _____ (positive/negative)
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negative.
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Amount of energy that reactant molecules must absorb to start a reaction.
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Energy of activation
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Unstable condition of reactant molecules that have absorbed sufficient free energy to react.
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Transition state
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An energy-requiring reaction that proceeds with a net gain of free energy.
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Endergonic reaction |
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An _____ reaction is one that requires free energy from its surroundings.
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endergonic
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Δ G of an endergonic reaction is ____ (positive/negative)
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positive.
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reaction in which the rates of forward and backward reactions are equal and there is no change in the concentration of products or reactants.
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Chemical Equilibrium
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The ΔG of a reaction at equilibrium is ______
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Zero
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To do work, cells manage energy resources by energy coupling, the use of an ___ process to drive an ____ one
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exergonic/endergonic
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Nucleoside triphosphate with unstable phosphate bonds that the cell hydrolyzes for energy to drive endergonic reactions.
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ATP (adenosine triphosphate) |
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The bonds between the phosphate groups of ATP’s tail can be broken by ____ reactions
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hydrolysis
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List the three main kinds of work of ATP.
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1. Chemical work such as driving endergonic reactions such as the synthesis of polymers from monomers |
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Chemical agent that accelerates a reaction without being permanently changed in the process, so it can be used over and over. |
Catalyst
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Biological catalysts, which are usually proteins.
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Enzymes
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Enzymes catalyze reactions by lowering the _____
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EA barrier |
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The substance an enzyme acts on and makes more reactive.
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Substrate
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Change in the shape of an enzyme's active site, which is induced by the substrate.
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Induced fit
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Restricted region of an enzyme molecule which binds to the substrate.
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Active site
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List the 4 mechanisms that enzymes use to lower activation energy and speed a reaction |
1. orients substrates
2. put stress on bonds that must be broken, making it easier to reach the transition state. 3. favorable microenvironment for a specific reaction. 4. Enzymes may even bind covalently to substrate |
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List the environmental factors that can effect enzyme rate. |
1.Temperature |
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Small non-protein molecules that are required for proper enzyme catalysis. |
Cofactors
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a non-protein organic cofactor.
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Coenzyme
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The protein portion of an enzyme.
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Apoenzyme
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The apoenzyme plus its coenzyme or cofactor.
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Holoenzyme
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molecules that bind to enzymes and prevent enzymes from catalyzing reactions. |
Inhibitors
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Chemicals that resemble an enzyme's normal substrate and compete with it for the active site. |
Competitive inhibitors
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Enzyme inhibitors that do not enter the enzyme's active site, but bind to another part of the enzyme molecule |
Noncompetitive inhibitors
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Enzymes are proteins encoded by ___
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genes
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Mutations (changes) in genes lead to changes in ____ of an enzyme
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amino acid composition
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Altered amino acids in enzymes may alter their shape and affect ______.
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substrate specificity
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Specific receptor site on some part of the enzyme molecule other than the active site.
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Allosteric site
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stabilizes the active form of the enzyme
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Activators
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stabilizes the inactive form of the enzyme
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Inhibitor
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Regulation of a metabolic pathway by its end product, which inhibits an enzyme within the pathway.
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Feedback inhibition
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How can the localization of enzymes within a cell help order metabolism |
1.Metabolic pathway assembled in a multienzyme complex
2.Fixed locations within the cell as structural components of membranes 3.In solution, within an organelle with its own internal microenvironment |
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Endergonic or exergonic?
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endergonic
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Endergonic or exergonic? |
exergonic
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spontaneous or non-spontaneous? |
non-spontaneous
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spontaneous or non-spontaneous?
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spontaneous
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Substrates are ___energy and products are ____ energy. |
low
high |
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Substrates are ___energy and products are ____ energy. |
high
low |
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negative or positive ΔG? |
positive
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negative or positive ΔG?
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negative
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Does this reaction absorb or release energy (net)?
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absorb
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Does this reaction absorb or release energy (net)?
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release
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What are the sections of the graphs labeled A-D? |
A free energy of substrate |