Term
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Definition
| Energy of motion: pushing a book off a desk, the P.E. is converted to KE, as it drops. (KE can be used to do work-ie, work=bruised foot) the PE in a chemical bond is released when the bond is broken, here, work=formation of new chemical bonds] |
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Term
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Definition
| Stored energy:the capacity to do work, energy of position [book on a desktop, atoms held in position in a chemical bond, individual electrons in an atom---each e- shell has a specific energy level] |
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Term
| 1st Law of Thermodynamics |
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Definition
| AKA-conservation of Energy. Energy cannot be created or destroyed, but only converted from 1 form to another |
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Term
| 2nd Law of Thermodynamics |
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Definition
| expresses the concept of entrophy. no energy conversion is 100% effective. some energy is lost as heat with each transfer,. therefore, with each successive energy conversion, the orderliness of the system becomes less |
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Term
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Definition
| the chemical rxns that take place in cells happen in a controlled, orderly manner, The energy released in this RNX is NOT entirely lost as heat. Cells couple rxns that release energy w/ those that require energy. (coupled, or paired) |
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Term
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Definition
| rxns that release energy. (exothermic="heat-releasing") exergonic -the fact that most of the released energy is NOT in the form of heat, but is transfered to other chemical rxns |
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Term
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Definition
| rxns that require energy. in a cell, rxns receive energy in the form of Energy-Carrier molecules-transfer energy from exergonic to endergonic |
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Term
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Definition
| 1 type transports energy in the form of high-energy chemical bonds. The other type transports energy in the form of excited electrons. carried on electrons |
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Term
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Definition
| most universal & important of the Energy carrier molecules. 1 nucleotide, 1 pentose sugar, 3 phosphate groups attached by high energy phosphate bonds. Energy is released as each phosphate is removed from the molecule. Reaction is REVERSIBLE. Held in high energy phosphate bonds |
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Term
| Electron Carrier Molecules |
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Definition
| AKA coenzymes. exist in 2 forms-oxidizing agent-->accepts electrons and becomes reduced. electrons are carried to where they're needed afor energy level. 2nd form is a reducing agent-->donates electrons and becomes oxidized. When the reduced form takes on electrons, H are carried along w/ them. |
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Term
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Definition
| the sum of all the chemical rxns that take place in a cell. metabolic rxns have 2 categories,depending on energy flow. Anabolic and Catabolic. |
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Term
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Definition
| are endergonic. large, energy rich compounds are synthesized from small, energy poor precursors. Photosynthesis is an example. |
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Term
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Definition
| are exergonic. Energy rich compounds are broken down for energy into smaller, simpler molecules. cellular respiration is an example |
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Term
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Definition
| a rnx reaches chem. equil. when its running at the same rate in both directions. the amounts of product & reactant are seldom the same at this time. |
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Term
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Definition
| the concentration of the compounds on either side can push or pull a reversible rxn. Increasing concentration 1 side PUSHES the rxn toward the other side. decreasing concentration on 1 side PULLS the rxn toward that same side |
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Term
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Definition
| the compound formed at the end of a pathway |
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Term
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Definition
| compunds that form between the start & conclusion of a rxn or pathway |
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Term
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Definition
| the compounds that an enzyme "works" on |
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Term
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Definition
| Protein catalysts. speed the rate of rxn, do NOT get used up of permanently altered in the rxn, do NOT alter the energy content of the product of reactants, do NOT alter the nature of the rnx (endergonic or exergonic). Unlike inorganic catalysts, enzymes are very specific about which rxns they'll catalyze (each rxn has a unique enzyme catalyst) can usually catalyze in both directions of a reversible rxn |
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Term
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Definition
| a chem rxn occurs when molecules collide w/ enough energy to break of reform bonds. the minimal amount of energy is the ACTIVATION ENERGY. enzymes lower the act. energy of a rxn |
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Term
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Definition
| a crevice in enzyme structure.the site of the interaction between enzyme and substrates. |
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Term
| Induced fit model (or enzyme action) |
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Definition
| enzyme is not just a passive location for the rxn. once the substrate enters the active site, the site can put strains on the bonds of substrate molecules. Straining the bonds can speed up the rxn. Substrate bonds will breack easier b/c they are slready "pre-stressed" |
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Term
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Definition
being in the active site can help substrates find each other. (localized boost in concentration. holds participants in place.) Can also orient substrates into favorable positions. (molecules need to bump into 1another in the right place for a bond to form. Active site turns these places towards each other so they can react.)
Cal also shift the electric charges in substrates, making them more likely to react. Can have a favorable pH environment. Can shut out water, creating a non-polar environment (helps break bonds in some rxns) |
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Term
| Factors influencing enzyme activity: temperature |
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Definition
| fast molecules collide more often. initial effect of temp increase speeds up rxns.unlike inorganic catalysts, too much heat breaks up the enzyme's tertiary structure, ruins active site, & stops the rxn. (denaturation) |
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Term
| Factors influencing enzyme activity: pH |
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Definition
| shape of a protein is determined by H bonds. addition or removal of H will affect H bonds, alter structure of enzyme, & alter it's activity |
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Term
| Factors influencing enzyme activity: Salts (ions) |
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Definition
| any charged particles can affect H bonding. adding salt will affect enzyme's tertiary structure |
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Term
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Definition
| another substance (not the substrate) combines w/ the enzyme at a site other than the active site. this rxn alters the shape of the enzyme (& it's active site) which alters the enzyme's catalytic activity |
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Term
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Definition
| used to control an enzyme that is normally in the "on" position. when the allosteric substance fits into the allosteric site, enzyme action is inhibited. the allosteric inhibitor alters the shape of the active site and turns it "off" |
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Term
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Definition
| serves as a control mechanism for many processes in living organisms. occurs when an ongoing process is inhibited (stopped) by an end product of the process. |
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Term
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Definition
| total amount of energy in a system will flow from forms rich in energy to forms w/ less of it. each time a living thing uses energy, some is lost as heat |
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Term
| What do enzymes do to activation energy? |
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Definition
| Enzymes Lover activation energy |
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