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107 Cards in this Set
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species
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A population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups
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cladogenesis
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A process in which a new species arises and the new and parental species coexist
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speciation
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An evolutionary process in which one species splits into two or more species
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biological species concept
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Defines a species as a group of individuals who interbreed or have the potential to interbreed in nature; by this definition a new species exists when individuals of a population become sufficiently different and can no longer interbreed
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morphological species concept
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Defines a species as a group of individuals with shared morphologies (appearances); by this definition, if a group of organisms appears distinct from other groups, it constitutes a separate species
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evolutionary species concept (aka phylogenetic species concept)
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Defines a species as a group of organisms with a shared evolutionary history; by this definition, two species might actually be able to interbreed, yet because they have different histories they are considered different species
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reproductive isolation
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The existence of biological factors (barriers) that impede members of two species from producing viable, fertile offspring
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prezygotic barrier
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A reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted
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postzygotic barrier
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A reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults
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habitat isolation
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Case where two species occupy overlapping territory but use different habitats
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temporal isolation
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Prezygotic barrier where two species are receptive to mating at different times of the day (or different seasons)
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behavioral isolation
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Prezygotic barrier where two species do not interbreed because they exhibit different behaviors
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gametic isolation
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Prezygotic barrier where gametes do not form a zygote; for any number of reasons (morphological, chemical, or environmental) the fusion of gametes does not occur
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mechanical isolation
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Prezygotic barrier where differences in size and shape of genitalia (or flower structures) prevent successful mating
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reduced hybrid viability
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Postzygotic barrier in which hybrids lack vigor and rarely, if ever, reach sexual maturity; these offspring are nonviable because they are ultimately unable to reproduce
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reduced hybrid fertility
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Postzygotic barrier in which interbreeding between species occurs and hybrids are formed, but the hybrids themselves are usually sterile
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hybrid breakdown
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Postzygotic barrier in which hybrids are capable of reproducing but their offspring have either reduced fertility or reduced viability
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allopatric speciation
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The formation of new species in populations that are geographically isolated from one another
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sympatric speciation
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The formation of new species in populations that live in the same geographic area
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adaptive radiation
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Period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities
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polyploidy
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A chromosomal alteration in which the organism possesses more than two complete chromosome sets; it is the result of an accident of cell division
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exaptations
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Structures that arise and are used in one context but in another context have different or additional functions
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evo-devo
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Evolutionary developmental biology; a field of biology that compares developmental processes of different multicellular organisms to understand how these processes have evolved and how changes can modify existing organismal features or lead to new ones
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homeotic genes
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The master regulatory genes that control placement and spatial organization of body parts in animals, plants, and fungi by controlling the developmental fate of groups of cells
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homeosis
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The general term for any mutation that results in a misplaced organ
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heterochrony
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An alteration in time, or a change in order, of one or more events
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paedomorphosis
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Describes a condition in which the timing of sexual maturity is altered (compared to the parental group)
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allometric growth
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Disproportionate growth; not all parts of the organ and/or organism grow at the same rate; results in an adult structure that is shaped differently than the juvenile structure
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plate tectonics
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The theory that the continents are part of great plates of Earth's crust that float on the hot, underlying portion of the mantle. Movements in the mantle cause the continents to move slowly over time
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continental drift
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The phenomenon in which the continents are constantly rearranging themselves
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Pangaea
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The supercontinent that all of the landmasses were joined as 250 million years ago
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fossil
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A preserved remnant or impression of an organism that lived in the past
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sedimentary rock
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Formed by layers of minerals that settle in water
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geological time scale
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Fossils are divided into age groups according to this, whereby explosions of life or mass extinctions mark the general age of Earth
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Precambrian, Paleozoic, Mesozoic, Cenozoic
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The four great eras of the geological time scale
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isotope
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One of several atomic forms of an element, each with the same number of protons but a different number of neutrons, thus differing in atomic mass
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radiometric dating
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A method for determining the absolute age of rocks and fossils, based on the half-life of radioactive isotopes
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radiocarbon dating (aka carbon-14 dating)
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Radiometric dating using carbon-14
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dendrochronology
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An absolute dating technique that uses growth rings in trees
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stromatolites
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Formations of sedimentary rock with a characteristic pattern
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abiotic
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Nonliving; referring to the physical and chemical properties of an environment
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monomers
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Small organic molecules
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protobiont
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Aggregates of polymers that are distinguishable from their surroundings
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metabolism
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The totality of an organism's chemical reactions, consisting of catabolic and anbolic pathways, which manage the material and energy resources of the organism
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energy
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The capacity to cause change, especially to do work (to move matter against an opposing force)
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kinetic energy
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The energy associated with the relative motion of objects. Moving matter can perform work by imparting motion to other matter
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potential energy
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The energy that matter possesses as a result of its location or spatial arrangement (structure)
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work
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The act of moving matter
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thermodynamics
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The study of energy transformations that occur in a collection of matter
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first law of thermodynamics
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The principle of conservation of energy: Energy can be transferred and transformed, but it cannot be created or destroyed
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second law of thermodynamics
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The principle stating that every energy transfer or transformation increases the entropy of the universe. Usable forms of energy are at least partly converted to heat
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free energy (G)
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The portion of a biological system's energy that can perform work when temperature and pressure are uniform throughout the system. The change in free energy of a system is deltaG=deltaH-TdeltaS
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endergonic reaction
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A nonspontaneous chemical reaction, in which free energy is absorbed from the surroundings
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exergonic reaction (delta G is negative)
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A spontaneous chemical reaction, in which there is a net release of free energy
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exothermic
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Describes a reaction with negative deltaH (heat is released)
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endothermic
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Describes a reaction with positive deltaH (heat is absorbed)
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mechanical, transport, chemical
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Three types of work
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adenosine triphosphate (ATP)
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An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive reactions in cells
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energy coupling
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The use of an exergonic (energy-releasing) process to drive an endergonic (energy-requiring) process
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cellular respiration
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The catabolic pathways of aerobic and anaerobic respiration, which break down organic molecules and use an electron transport chain for the production of ATP
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redox
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The transfer of electrons that occurs during many chemical reactions (reduction-oxidation)
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electronegativity
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Affinity for electrons
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NAD+
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Nicotinamide adenine dinucleotide, a coenzyme that cycles easily between oxidized (NAD+) and reduced (NADH) states, thus acting as an electron carrier.
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cytosol
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The semifluid portion of the cytoplasm; where glycolysis takes place
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glycolysis
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A series of reactions that ultimately splits glucose into pyruvate. It occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration
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substrate-level phosphorylation
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The enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism
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fermentation
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A catabolic process that makes a limited amount of ATP from glucose (or other organic molecules) without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid
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alcohol fermentation
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Glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD+ and releasing carbon dioxide
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lactic acid fermentation
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Glycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide
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Krebs Cycle
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A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA to carbon dioxide; occurs within the mitochondrion in eukaryotic cells and in the cytosol of prokaryotes; together with pyruvate oxidation, the second major stage in cellular respiration
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mitochondrion
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An organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP
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electron transport chain
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A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP
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terminal electron acceptor
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Oxygen acts as this during the electron transport chain
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mitochondrial matrix
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The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the citric acid cycle, as well as ribosomes and DNA
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chemiosmosis
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An energy-coupling mechanism that uses energy stored in the form of a hydrogen ion gradient across a membrane to drive cellular work, such as the synthesis of ATP. Under aerobic conditions, most ATP synthesis in cells occurs by this
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ATP synthase
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A complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. These are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes
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oxidative phosphorylation
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The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration
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activation energy
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The amount of energy that reactants must absorb before a chemical reaction will start
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catalyst
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A chemical agent that selectively increases the rate of a reaction without being consumed by the reaction
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enzyme
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A macromolecule serving as a catalyst, a chemical agent that increases the rate of a reaction without being consumed by the reaction; most are proteins
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substrate
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The reactant on which an enzyme works
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active site
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The specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs
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enzyme-substrate complex
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A temporary complex formed when an enzyme binds to its substrate molecule(s)
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coenzyme
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An organic molecule serving as a cofactor; most vitamins function as these in metabolic reactions
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feedback inhibition
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When a reaction's end products inhibit the reaction itself by halting it when a certain amount of product has accumulated
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allosteric regulation
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When an inhibitor binds to a site distant from the active site and causes a conformational change in the enzyme thereby decreasing its ability to bind with the substrate and hence catalyze the reaction
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allosteric enzymes
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Intricate molecules, composed of at least two protein subunits; conformational changes occur when allosteric sites are filled thereby changing the shape of the active site itself
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phosphofructokinase (PFK)
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An important enzyme that is involved in the early stages of glycolysis
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kinases
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A family of enzymes that move phosphate groups from energy-containing molecules to other organic molecules
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endosymbiosis
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When one organism began living within the body of another
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serial endosymbiosis
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Sequential endosymbiotic events
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extant
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Currently existing
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photosynthesis
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The process by which plants convert light energy into chemical energy (they use light, water, and CO2 to make sugars)
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photochemistry
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The sun's energy is transformed into electrical energy
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thylakoid
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A flattened, membranous sac inside a chloroplast
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chloroplast
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An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water
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photosystem
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A light-capturing unit located in the thylakoid membrane of the chloroplast or in the membrane of some prokaryotes, consisting of a reaction-center complex surrounded by numerous light-harvesting complexes
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photosystem I
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A light-capturing unit in a chloroplast's thylakoid membrane or in the membrane of some prokaryotes; it has 2 molecules of P700 chlorophyll a at its reaction center
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photosystem II
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A light-capturing unit in a chloroplast's thylakoid membrane or in the membrane of some prokaryotes; it has 2 molecules of P680 chlorophyll a at its reaction center
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NADP+
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An electron acceptor that, as NADPH, temporarily stores energized electrons produced during the light reactions
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photophosphorylation
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The process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated across the thylakoid membrane of the chloroplast or the membrane of certain prokaryotes during the light reactions of photosynthesis
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ribulose biphosphate (RuBP)
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The recycled molecule in the Calvin cycle; a five-carbon compound that joins with a carbon dioxide to form a six-carbon compound that quickly breaks into two
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chromatography
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The technique that Calvin used to determine which molecules had incorporated the carbon-14
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rubisco
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The most abundant protein on Earth; an enzyme that helps join one molecule of CO2 with one molecule of RuBP
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stomata
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Pores in the leaves that carbon dioxide comes in through
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glyceraldehyde 3-phosphate (G3P)
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A 3-carbon molecule that the two 3-carbon molecules from RuBP are reduced to in the Calvin cycle
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carbon cycle
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The relationship where carbon dioxide is constantly being fixed into sugars which are then oxidized back into CO2
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