| Term | Definition |
|---|
| what is energy? | the capacity to do work |
| what does chemical work enable? | cells and organisms to grow, reproduce, and carry out normal activities |
| what does transport work enable? | cells to move molecules to create concentration gradients |
| what is mechanical work used for? | movement |
| what does the first law of thermodynamics state? | 1. total amount of energy in the universe is constant; 2. energy can not be created nor destroyed |
| what is kinetic energy? | energy of motion |
| what is potential energy? | stored energy |
| what does chemical reaction begin and end with? | one or more reactants and ends with one or more products |
| what is reaction rate measured as? | the change in concentration of products with time |
| what is the free energy of the molecule? | the energy stored in the chemical bonds of a molecule and available to perform work |
| what is activation energy? | the initial input of energy required to begin a reaction |
| what are exergonic reactions? | energy-producing; release energy because the products have less energy than the reactants |
| what are endergonic reactions? | energy-utilizing; trap some activation energy in the products, which then have more free energy than the reactants |
| what do metabolic pathways couple? | exergonic reactions to endergonic reactions |
| where is energy for driving endergonic reactions stored? | ATP |
| what is a reversible reaction? | a reaction that can proceed in both directions |
| what is an irreversible reaction? | a reaction that can proceed in one direction but not the other |
| what determines whether a reaction can be reversed? | the net free energy change of a reaction |
| what are enzymes? | biological catalysts that speed up the rate of chemical reactions without themselves being changed |
| what are substrates? | the reactants in reactions catalyzed by enzymes |
| what does enzyme react with? | only limited and selected substrate "specificity" |
| what do enzymes contain? | both active and non-active sites |
| what do competitive inhibitors bind to? | active site |
| what does induced fit model state? | that neither the substrate nor the products can bend to bind with the enzyme, the enzyme must bend to allow reaction |
| what is denatured? | when an enzyme's activities are changed or destroyed by the temperature and pH (modulators) |
| what is feedback inhibition an example of? | negative feedback that inhibits the activity of early enzymes and usually involves modification of enzyme |
| what do enzymes exhibit? | like other proteins that bind ligands, they exhibit saturation, specificity, and competition. however, related isozymes may have different activities |
| what happens with enzymes that are produced as inactive precursors? | they must be activated |
| what does activation of an inactive precursor require? | the presence of a cofactor |
| what are organic cofactors called? | coenzymes |
| what acts as co-factors and co-enzymes in metabolic reactions of the cell? | molecules such as vitamin C and biotin |
| what alters enzyme activity? | temperature, pH, and modulator molecules |
| how do enzymes work? | by lowering the activation energy of a reaction |
| what state do reversible reactions go to? | equilibrium |
| what is equilibrium? | when the rate of the reaction in the forward direction is equal to the rate of the reverse reaction |
| what do reversible reactions obey? | the law of mass action |
| what is the law of mass action? | when a reaction is at equilibrium, the ratio of substrates to products is always the same. |
| what happens to disturb equilibrium? | the concentration of a substrate or product changes |
| how can most reactions be classified? | oxidation-reduction, hydrolysis-dehydration, addition-subtraction-exchange, or ligation reactions |
| what does glycolysis convert glucose to? | pyruvate |
| what are properties of living organisms? | 1. have a highly organized, complex structure; 2. acquire, transform, store, and use energy; 3. sense and respond to internal and external environments; 4. maintain homeostasis through internal control systems with feedback; 5. store, use, and transmit information; 6. reproduce, develop, grow and die; 7. have emergent properties that cannot be predicted from the simple sum of the parts; 8. species evolve |
| what does the second law of thermodynamics state? | processes move from state of order to disorder or entropy |
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