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37 Cards in this Set
- Front
- Back
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Metabolism
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all the chemical reactions in an organism; manages the matter and energy resources of a cell.
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Metabolic Pathway
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begins with a specific molecule, reacts in certain steps, and results in a specific product.
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Metabolic Enzymes
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regulate the metabolic pathway, balance supply and demand.
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Catabolic pathways
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release energy; cellular respiration
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Anabolic pathways
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consume energy; build complex molecules.
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Energy
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the capacity to cause change.
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Work
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moves matter against opposing force.
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Thermodynamics
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study of energy transformation.
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2nd Law of Thermodynamics
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every time energy is transferred/transformed, most of it becomes unusable and given off as heat.
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Entropy
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measure of randomness or disorder.
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Gibbs free energy of a system
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measures the portion of a system's energy that can actually be used for work.
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Free Energy(G)
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energy that can do work when temp. and pressure are uniform.
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Which processes are spontaneous?
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those with a negative (G).
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Enthalpy, deltaH
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change in total energy.
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What processes result in a loss of free energy?
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spontaneous.
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Endergonic
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nonspontaneous, consumes energy.
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Exergonic
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spontaneous, releases energy.
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deltaG
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change in the amount of energy that can be used to do work.
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deltaS
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change in the disorder of a system.
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Closed System
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reactions eventually reach equilibrium and then do no work.
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Open System
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experience a constant flow of materials; cells not at equilibrium.
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3 main kinds of work?
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mechanical, chemical, and transport.
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Mechanical work
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beating of cilia, muscle contraction.
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Transport work
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pump substances across membrane against the concentration gradient.
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ATP
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reactants (ATP and water) have high energy relative to the energy of the products (ADP and Pi). physically rearranges molecules to lower energy states.
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Phosphorylation
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transfer phosphate group from ATP to another molecule.
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How is ATP regenerated?
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adding a phosphate group to ADP.
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Catalyst
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chemical agent that speeds up a reaction without being consumed by it.
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Activation Energy
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initial energy needed to start a chemical reaction.
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Enzyme
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lowers activation energy but products ALWAYS equal reactants.
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What does heat do for a chemical reaction?
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denature proteins, kill cells, speeds up reaction.
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Substrate
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reactant that an enzyme acts on.
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Active Site
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region where substrate binds enzyme.
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How do enzymes bond to substrate?
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weak bonds, hydrogen or ionic.
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How do enzymes lower Ea?
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orienting substrates correctly, strainin substrate bonds, provide favorable microenvironment.
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Rate of Enzymatic rxn's
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depends on concentrations of reactants and products and determined by speed at which substrates are converted.
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What affects enzyme activity?
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temperature, pH, and certain chemicals.
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