| A | B |
|---|
| metabolism | the totality of an organism's chemical processed |
| catabolic pathways | release energy by breaking down complex molecules to simpler compounds, ex. cellular respiration, energy becomes available to do work in the cell, downhill |
| anabolic pathways | consume energy to build molecules from simpler ones, uphill |
| bioenergetics | study of how organisms manage their energy resources |
| energy | the capacity to do work |
| potential energy | the energy that matter possesses because of its location or structure |
| thermodynamics | the study of the energy transformations that occur in a collection of matter |
| first law of thermodynamics | the energy of the universe is constant, also called conservation of energy |
| second law of thermodynamics | every energy transfer of transformation increases the entropy of the universe |
| free energy | energy available to preform work when temperature is uniform throughout the system |
| exergonic reaction | net release of free energy, -deltaG is the maximum amount of work the reaction can perform, downhill (catabolic) |
| the amount of energy given off by the exergonic process, cellular respiration | -686 kcal/mol |
| endergonic reaction | absorbs free energy from surroundings, +deltaG, nonspontaneous, uphill (anabolic), ex. photosynthesis |
| metabolic disequilibrium | since deltaG cannot = 0 (death), it is a defining feature fo life |
| energy coupling | the use of an exergonic process to drive an endergonic one, mediated mostly by ATP |
| ATP | adenosine triphosphate, made of nitrogenous base adenine bonded to a ribose bonded to three phosphate groups (the tail which can be easily hydrolyzed) |
| phosphorylated intermediate | the reciepient of a phosphate group which is more reactive (less stable) than originally |
| enzymes | catalytic proteins |
| catalyst | chemical agent that changes the rate of a reaction without being used up |
| free energy activation, activation energy | energy that initiates the reaction, breaks bonds in the reactant molecules |
| substrate | the reactant an enzyme acts on |
| active site | restricted region where enzyme binds to the substrate |
| induced fit | substrate induces the enzyme to change its shape it fit better which enhances its catalytic abilities |
| cofactors | requi9red by some enzymes for catalytic activity, nonprotein, inorganic, ex. metals zinc, iron, copper |
| coenzyme | organic enzyme helper, ex. vitamins |
| conpetitive inhibitors | mimics that reduce the productivity of enzymes by blocking the active site, reversible |
| noncompetitive inhibitors | impede enzymatic reactions by binding to another part of the enzyme causing enzyme to change shape |
| allosteric site | where molecules that regularly regulate enzyme activity binds, like reversible noncometitive inhibitors |
| feedback inhibition | switching off of a metabolic pathwayby its end product, acts as inhibitor of an enzyme within the pathway |
| cooperativity | when one substrate molecule primes an enzyme to accept additional substrate molecules by changing the shape of the enzyme |
| fermentation | partial degredation of sugars without the help of oxygen |
| cellular respiration | catabolic, oxygn is consumed along with the organic fuel, usually in mitoc. |
| redox reactions | electron transfers where a substances loses an electron (oxidation) and another gains electrons (reduction) |
| reducing agent | the electron donor |
| oxidizing agent | the electron acceptor |
| NAD+ | nicotinamide adenine dinucloetide, oxidizing agent during respiration, a coenzyme |
| electron transport chain | break the fall of electrons to oxygen into several energy releasing steps |
| Glycolysis | first metabolic stage, catabolic pathway that decomposes glucose and other organic fuels, occurs in cytosol, breaks glocose into pyruvate |
| Krebs cycle | second metabolic stage, catabolic pathway that decomposes glucose and other organic fuels, occurs in mitoch. matrix, decomposes a derivative of pyruvate to carbon dioxide |
| oxidative phosphorylation | fnal metabolic stage, mode of ATP synthesis powered by redox reactions that transfer electrons from food to oxygen |
| substrate-level phosphorylation | mode of ATP synthesis that occurs when an enzyme transfers a phosphate group from a substract to ADP |
| acetyl CoA | formed from pyruvate upon entering the mitoch. |
| ATP synthase | found in inner membrane of mitoch., copies of a protein complex, actually makes ATP, works like an ion pump in reverse |
| chemiosmosis | coupling method for oxidative phosphorylation |
| proton-motive force | creates the capacity of the gradient to perform work |
| aerobic, anaerobic | with oxygen, without oxygen |
| alcohol fermentation | pyruvate is converted to ethanol in two steps |
| lactic acid fermentation | pyruvate is reduced directly by NADH |
| facultative anaerobes | organisms that can make enough ATP to survive either by fermentation or respiration (ex. yeasts, many bacteria) |
| beta oxidation | metabolic sequence that breaks down fatty acids into 2-carbon fragments which enter the Krebs cycle as CoA |
| autotrophs | self-feeders, producers |
| heterotrophs | live on compounds others produce, consumers |
| mesophyll | tissue in interior of leaf, where chloroplasts are |
| stomata (sing. stoma) | pores in leaf by which o2 exists and co2 enters |
| net photosynthesis rxn | CO2 + H2O = CH2O + O2 |
| light reactions | stage of photosynthesis that converts solar energy to chemical energy |
| Calvin cycle | stage fo photosyn. that converts 3CO2 to G3P using ATP and NADHP from light reactions |
| NADP+ | electron acceptor in photosyn., shuttle |
| photophosphorylation | mode of ATP synthesis driven by photosyn. |
| carbon fixation | initial incorporation of C into organic cmpds |
| wavelength | distance between crests of electromagnetic waves |
| electromagnetic spectrum | entire range fo radiation |
| visible light | range we can detect, 380-750 nm |
| photons | discrete particles of light |
| spectrophotometer | measures the ability of a pigment to absorb various wavelenghts of light |
| absorption spectrum | graph plotting a pigment's light absorption vs wavelength |
| action spectrum | profiles the relative performance of the different wavelengths more accurately thatn the absorption spectrum, plots wavelenght vs some measure of photosynthetic rate |
| chlorophyll a | participates directly in the light reactions that convert solar E to chemical E, blue-green |
| chlorophyll b | accessory pigment, yellow-green, transfers its absorbed photons to chlo. a |
| carotenoids | hydrocarbons, accessory pigments, yellow and organge, broaden spectrum of colors and serve in photoprotection |
| photosystems | antenna complex (chlorophylls/carotenoids), proteins, sm organic molecules |
| primary electron acceptor | accepts the excited electrons from reaction center |
| reaction center | center chlor. a molecule, where first light-driven chemical reactions occur |
| photosystem I | P 700, gives its elctied electrons to its primary acceptor, they then fall and reduce NAPD+ |
| photosystem II | gives excited electron to its primary electron acceptor, they then fall making ATP by chemiosmosis and fill the "hole" in photosystem I |
| noncyclic electron flow | use of photosystems I and II to create ATP (noncyclic photophosphorylation) and NADPH + H+ |
| cyclic electron flow | use of only photosystem I to make only ATP (cyclic photophosphorylation) |
| glyceraldehyde 3-phosphate | carb produced by Calvin cycle from 3CO2 |
| phases of Calvin cycle | carbon fixation, reduction, regeneration of RuBP |
| rubisco | enzyme that catalyzes the incorporation of CO2 by attaching it to a 5C called ribulose bisphosphate (BuBP) |
| C3 plants | plants that fix C via rubisco by adding CO2 to RuBP producing two 3-phosphoglycerate |
| photorespiration | when CO2 is scarce rubisco will accept O2 in its place, the product splits into a 2C cmpd which is exported to the mitoch. and peroxisomes where they are broken into CO2 (process consumes O2 and occurs in light), generates no ATP or food, decreases photosyn. output |
| C4 plants | alternate mode of C fixation that forms a $c cmpd as its first element |
| bundle-sheath cells | arranged in tightly packed sheaths around the leaf veins, Calvin cycle confined to the chloroplasts here for C4 plants |
| mesophyll cells | b/w bundle-sheath cells and leaf surface, more loosely arranged, where CO2 is fixed in C4 plants |
| PEP carboxylase | enzyme that adds CO2 to PEP (3C) in C4 plants to produce a 4C molecule |
| crassulacean acid metabolism, CAM | mode of carbon fixation adapted to arid conditions, take up CO2 at night theough stomata which close during the day |
| CAM plants | mesophyll cells store the organic acids made at night, release CO2 from organic acids during the day |
