front 1 metabolism | back 1 the totality of an organism's chemical reactions - manages the material and energy resources of the cell - living systems require a constant input of energy and exchange of macromolecules |
front 2 metabolic pathway | back 2 a specific molecule is altered in a series of defined steps, resulting in a certain product - each step is catalyzed by a specific enzyme |
front 3 catabolic pathways | back 3 "breakdown pathways" - metabolic pathways that lead to the release of energy by the breakdown of complex molecules to simpler compounds ex. digestive system enzymes break down food and release energy |
front 4 anabolic pathways | back 4 "biosynthetic pathways" - consume energy to build complicated molecules from simpler ones ex. linking of amino acids to form muscle protein in response to physical exercise |
front 5 energy | back 5 the capacity to do work / cause change - the ability to rearrange a collection of matter |
front 6 note about pathways | back 6 energy released from downhill reactions of catabolic pathways can be stored and then used to drive the uphill reactions of anabolic pathways |
front 7 bioenergetics | back 7 the study of how energy flows through living organisms |
front 8 kinetic energy | back 8 - associated with the relative motion of objects possessed by anything that is moving (moving objects can perform work by imparting motion to other matter) |
front 9 thermal energy | back 9 kinetic energy associated with the random movement of atoms or molecules |
front 10 heat | back 10 - thermal energy in transfer from one object to another |
front 11 light | back 11 also a type of energy - can be harnessed to perform work, such as powering photosynthesis in green plants |
front 12 potential energy | back 12 - energy that matter possesses due to its location or structure |
front 13 chemical energy | back 13 - potential energy available for release in a chemical reaction - stored in molecules - amount of this energy a molecule possesses depends on its chemical bonds |
front 14 biochemical pathways... | back 14 - enable cells to release chemical energy from food molecules and use the energy to power life processes |
front 15 organisms are... | back 15 - energy transformers |
front 16 thermodynamics | back 16 the study of energy transformations that occur in matter |
front 17 first law of thermodynamics | back 17 the energy of the universe is constant - energy can be transferred and transformed, but it cannot be created or destroyed |
front 18 second law of thermodynamics | back 18 - in every energy transfer the potential energy of the final state is less than the potential energy of the initial state - every energy transfer or transformation increases the entropy of the universe energy cannot be recycled (some energy is converted into thermal energy and released as heat - becomes unavailable to do work) living things must have a constant inflow of energy |
front 19 each energy transfer or transformation makes... | back 19 the universe more disordered |
front 20 entropy | back 20 a measure of molecular disorder or randomness |
front 21 spontaneous process | back 21 - energetically favorable - leads to an increase in entropy - do not require energy to occur |
front 22 nonspontaneous | back 22 - leads to decrease in entropy - will only happen if energy is supplied |
front 23 living systems... | back 23 increase the entropy of their surroundings |
front 24 free energy | back 24 - the part of a system's energy that is able to perform work (when the temperature and pressure of a system are uniform) - measure of a system's instability; tendency to change to a more stable state |
front 25 Gibbs free energy used in biology... | back 25 to predict which kinds of change can happen without an input of energy - such spontaneous changes can be harnessed by the cells to perform work |
front 26 a process is spontaneous and can perform work only when... | back 26 it is moving toward equilibrium |
front 27 exergonic reaction | back 27 energy is released - occur spontaneously - release free energy into the system G <0 |
front 28 endergonic reaction | back 28 requires energy to proceed - absorb free energy - require free energy from the system G>0 |
front 29 metabolism at a whole... | back 29 is never at equilibrium (this is one of the defining features of life) |
front 30 energy coupling | back 30 - a key feature in the way that cells manage their energy resources to do cell work - the use of a rxn that releases energy to drive a reaction that requires energy (exergonic -> endergonic) |
front 31 ATP | back 31 - primary source of energy in cells - when a phosphate group is hydrolyzed, energy is released in an exergonic reaction - mediates energy coupling in cells |
front 32 ATP structure | back 32 - nitrogenous base adenine - bonded to ribose - chain of three phosphates |
front 33 work in the cell is done by... | back 33 the release of a phosphate group from ATP - exergonic release of the phosphate group is used to do endergonic work of the cell |
front 34 When ATP transfers one phosphate group through hydrolysis, it becomes... | back 34 ADP |
front 35 three types of cellular work | back 35 chemical work, transport work, and mechanical work |
front 36 chemical work | back 36 the pushing of endergonic reactions that would not occur spontaneously |
front 37 transport work | back 37 pumping of substances across membranes against the direction of spontaneous movement |
front 38 mechanical work | back 38 such as the beating of cilia, the contraction of muscles, and the movement of chromosomes during cellular reproduction |
front 39 phosphorylation | back 39 - the transfer of a phosphate group from ATP to some other molecule |
front 40 how can ATP be regenerated? | back 40 - by the addition of the phosphate to ADP |
front 41 catalysts | back 41 - substances that can change the rate of reaction without being altered in the process |
front 42 enzymes | back 42 - macromolecules that are biological catalysts - speed up metabolic processes by lowering energy barriers |
front 43 activation energy | back 43 - the amount of energy it takes to start a reaction - the amount of energy it takes to break the bonds of the reactant molecules |
front 44 substrate | back 44 the reactant that an enzyme acts on |
front 45 active site | back 45 - the part of the enzyme that binds to the substrate |
front 46 enzyme-substrate complex | back 46 what the enzyme and substrate form when bonded together - generally held together by weak interactions |
front 47 products | back 47 - substrate converted into this - released from enzyme |
front 48 factors that can affect enzyme activity | back 48 -changes in pH - changes in temperature (any changes in the precise shape of the enzyme usually mean the enzyme will not be as effective) |
front 49 denatured | back 49 - enzyme has lost its folded structure, is no longer able to function |
front 50 enzymes have... | back 50 optimal temperatures and pHs in which they function best at |
front 51 cofactors | back 51 - nonprotein enzyme helpers - function in some crucial way to allow catalysis to occur |
front 52 coenzymes | back 52 - organic cofactors ie. vitamins |
front 53 how are enzymes regulated? | back 53 - can be turned on and off |
front 54 competitive inhibitors | back 54 - molecules that compete with the substrate for the active site on the enzyme - may bind reversibly or irreversibly to the active site - often very similar to the normal substrate molecule and reduce the efficiency of the enzyme as it competes for the active site |
front 55 noncompetitive inhibitors | back 55 - do not directly compete with the substrate molecule to bind to the active site - they impede enzyme activity by binding to another part of the enzyme - causes the enzyme to change its shape, often rendering the active site nonfunctional |
front 56 concentration of enzymes and substrates... | back 56 - can also affect the efficiency of an enzymatic reaction assuming abundant substrate, an increase in enzyme concentration will lead to an increase in the production of the final product |
front 57 enzymes regulate biological activities by... | back 57 - increasing the rates of their reactions |
front 58 allosteric site | back 58 - a specific binding site on an enzyme that is not the active site - enzyme regulators bind to this - once bound, the shape of the enzyme is changed and this can either simulate or inhibit enzyme activity |
front 59 feedback inhibition | back 59 - increases the efficiency of a pathway by turning it off when the end product accumulates in the cell - the end product on an enzymatic pathway can switch off its pathway by binding to the allosteric site of an enzyme in the pathway |