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Bio Ch. 4-7 Flashcards

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1047036495Absorption spectrumRange of wavelengths that a given type of pigment can absorb.1
1047036496Accessory pigmentA pigment that absorbs and transfers light energy to a photo system; extends the range of light wavelengths for photosynthesis.2
1047036497ATP synthasesA type of membrane-bound active transport protein that also catalyzes the formation of ATP.3
1047036498AutotrophsAn organism that synthesizes its own food.4
1047036499C3 plantsType of plant in which three carbon PGA is the first stable intermediate to form after carbon fixation.5
1047036500C4 plantsType of plant in which four-carbon oxaloacetate is the first stable intermediate to form after initial carbon fixation; in these plants, carbon is fixed twice, in two different types of photosynthetic cells.6
1047036501Calvin-Benson cycleCyclic reactions that form sugar and regenerate RuBP in the second stage of photosynthesis. The reactions require carbon (from carbon dioxide). They use energy from ATP and hydrogens and electrons from NADPH, both of which form in the first stage7
1047036502CAM PlantsType of plant that conserves water by opening stomata only at night, when it fixes carbon by repeated turns of the C4 pathway; stand for crassulacean acid metabolism.8
1047036503Carbon fixationProcess by which any autotrophic cell incorporates carbon atoms into a stable organic compound. Different cells get carbon dioxide from the air or dissolved in water.9
1047036504CartenoidsOne of a class of accessory pigments in photosynthesis that reflected red, orange, and yellow light. One kind, beta-carotene, is a precursor of vitamin A.10
1047036505Chlorophyll aIn plants and algae, a pigment that is a receptor for the photon energy required to start photosynthesis; it absorbs mainly violet and red light and reflects or transmits green light.11
1047036506Chlorophyll bAn accessory pigment that absorbs mainly blue and orange light.12
1047036507ChloroplastsOrganelle of photosynthesis in plants and algae. Two outer membranes enclose a semifluid interior, the stroma. A third membrane forms a compartment inside that functions in ATP and NADPH formation; sugars form in the stroma13
1047036508CuticleOf plants, a cover of transparent waxes and cutin on the outer wall of epidermal cells. Of annelids, a thin and flexible coat. Of arthropods, a lightweight exoskeleton hardened with chitin.14
1047036509Cycle pathwaysOld photosynthetic pathway. Photon energy forces electrons out of membrane-bound photosystems to transfer systems, which return them to the photosystems. Electron flow across the membrane sets up H+ gradients that drive ATP formation.15
1047036510Electromagnetic spectrumAll wavelengths of photon energy from gamma rays less than 10-5 nanometers long to radio waves more than 10 kilometers long.16
1047036511Electron transfer chainsArray of enzymes and other molecules in a cell membrane that accept and give up electrons in sequence; operation of chain releases the energy of the electrons in small, usable increments.17
1047036512HeterotrophsOrganism that cannot make its own food.18
1047036513Light-dependent reactionFirst stage of photosynthesis. Pigments trap photon energy, which is transduced to ATP chemical energy. In a noncycle pathway, a reduced coenzyme, NAPDH, also forms.19
1047036514Light-independent reactionSecond stage of photosynthesis. Involves carbon fixation and cyclic reactions that form sugars and regenerate an organic compound that is the cycle's entry point. ATP from the first stage delivers energy that drives the reactions. NADPH from the first stage donates electrons and hydrogen building blocks. The carbon and nitrogen come from CO2.20
1047036515Noncyclic pathwayThe light-dependent reactions of photosynthesis that produce both ATP and NADPH; its oxygen by-product is the basis of Earth's oxygen-rich atmosphere21
1047036516PhotolysosReactions that split water molecules, which release electrons for the noncyclic pathway of photosynthesis; oxygen is a by-product.22
1047036517PhotosynthesisThe process by which photoautotrophs capture sunlight energy and use it in the formation of ATP and NADPH, then in the formation of sugars from carbon dioxide and water. ATP gives up energy that drives the sugar-building reactions, and NADPH donates electrons and hydrogen building blocks.23
1047036518PhotosystemsIn photosynthetic cells, a cluster of membrane-bound pigments and other molecules; it converts light energy to chemical energy.24
1047036519PigmentsAny light-absorbing molecule.25
1047036520Reaction centerAt a photosystem's center, a special pair of chlorophyll a molecules; the center loses electrons on absorption of photon energy, thereby initiating the lightdependent reactions of photosynthesis.26
1047036521StomataA gap between two plumped guard cells that lets water vapor and gases diffuse across the epidermis of a leaf or primary stem; diffusion stops when the cells lose water and collapse.27
1047036522StromaThe semifluid matrix between the thylakoid membrane system and two outer membranes of a chloroplast were sucrose, starch, cellulose, and other end products of photosynthesis are built.28
1047036523Thylakoid membraneA chloroplast's inner membrane system, often folded as flattened secs, that forms a continuous compartment in the stroma. In the first stage of photosynthesis, pigments and enzymes in the membrane function in the formation of ATP and NADPH29
1047036524WavelengthThe distance between the crests of two successive wavelike forms of energy in motion.30
1047036525Activation energyMinimum amount of energy required to start a reaction; enzyme action lowers this energy barrier. Reactions differ in the amount required.31
1047036526Active sitesChemically stable crevice in an enzyme where substrates bind and a reaction can be catalyzed repeatedly.32
1047036527ADPAdenosine disphosphate. A nucleotide with in adenine bind and two phosphate groups.33
1047036528AntioxidantsAny enzyme or cofactor that helps neutralize free radicals before than damage tissues.34
1047036529ATPAdenosine triphosphate. A type of nucleotide that functions as the main energy carrier between reaction sites in cells. Consists of the base adenine, the five-carbon sugar ribose, and three phosphate groups.35
1047036530ATP/ADP cycleHow a cell regenerates its ATP supply. ADP forms when ATP gives up a phosphate group, then ATP forms as ADP binds to inorganic phosphate or a phosphate group split from a molecule36
1047036531Binding energyEnergy released as weak bonds form between a substrate, enzyme, and any cofactor37
1047036532BioluminescenceFluorescent light formed when certain organisms convert chemical bond energy to photon energy.38
1047036533Biosynthetic pathway (anabolic)Any metabolic pathway by which one or more organic compounds are synthesized39
1047036534Chemical energyPotential energy in the bonds between atoms in molecules40
1047036535Chemical equilibriumNo net change in concentrations of reactants and products in a reversible chemical reaction.41
1047036536CoenzymesAn organic molecule that is a necessary participant in some enzymatic reactionsl helps catalysis by donating or accepting electrons or functional groups; e.g., a vitamin, ATP, NAD+42
1047036537CofactorsA metal ion or a coenzyme that assists an enzyme in catalysis by accepting or donating electrons or functional groups.43
1047036538Degradative pathway (catabolic)Any of the stepwise series of metabolic reactions that break down organic compounds.44
1047036539Endergonic reactionA chemical reaction that requires a net energy input and converts more stale reactants into less stable products; not spontaneous.45
1047036540EntropyMeasure of how much and how far a concentrated form of energy has been dispersed after an energy change.46
1047036541EnzymesA type of protein that catalyzes (speeds) a chemical reaction. Some RNAs also show catalytic activity.47
1047036542Exergonic reactionAny chemical reaction with a net energy loss.48
1047036543FADFlavin adenine dinucleotide. A tyoe of nucleotide coenzyme; transfers electrons and H+ from one reaction site to another.49
1047036544Feedback inhibitionMechanism by which a change that results from some cellular activity triggers responses that decrease or shut down the activity.50
1047036545First law of thermodynamicsEnergy cannot be created or destroyed51
1047036546Free radicalsAny unbound molecular fragment with an unpaired electron.52
1047036547Induced-fit modelExplanation of how some enzymes work; their shape changes and fits a bound substrate more closely, and the tension destabilizes substrate bonds so that they can break.53
1047036548IntermediatesA substance formed between the started and end of a metabolic pathway.54
1047036549Kilocalorie1,000 calories of heat energy; amount needed to raise the temperature of 1 kilogram of water by 1°C. Standard unit of measure for food's caloric content.55
1047036550Kinetic energyEnergy of morion56
1047036551Metabolic pathwaysA stepwise sequence of enzyme-mediated reactions.57
1047036552MetabolismAll the controlled, enzyme-mediated chemical reactions by which cells acquire and use energy as they synthesize, store, degrade, and eliminate substances.58
1047036553NAD+Nicotinamide adenine phosphate. A phosphorylated nucleotide coenzymel after it accepts electrons and H+, abbreviated as NADH59
1047036554NADP+Nicotinamide adenine dinucleotide phosphate. A phosphorylated nucleotide coenzyme; after it accepts electrons and H+, abbreviated NADPH2.60
1047036555Oxidation-reduction reactions (redox)Transfer of electrons between reactant molecules.61
1047036556PhosphorylationEnzyme-mediated transfer of a phosphate group to an organic compound.62
1047036557Potential energyAn object's capacity to do work owing to its position in space or the arrangement of its parts.63
1107543738actinProtein monomer of microfilaments that functions in contraction, cell division, and reinforcing or reconfiguring the shape of a cell or its contents.64
1107543739adhering junctionsComplex of adhesion proteins that anchors cells to each other and to extracellular matrixes.65
1107543740ArchaeaDomain of prokaryotic species; one of two lineages that evolved shortly after life originated. Archaeans have many unique molecular and biochemical traits but also share some traits with bacteria and other traits with eukaryotic species.66
1107543741BacteriaDomain of prokaryotic species; the first kinds of cells that formed after life originated. Collectively, bacteria are the most metabolically diverse organisms. Most kinds are chemoheterotrophs.67
1107543742basal bodyAn organelle that started out as a centriole, the source of a 9+2 array of microtubules in a cilium or flagellum. It remains below the finished array.68
1107543743cellSmallest unit that still displays the properties of life; it has the capacity to survive and reproduce on its own.69
1107543744cell cortexA dynamic mesh of crosslinked cytoskeletal elements just underneath the plasma membrane and attached to it.70
1107543745cell junctionsOf a tissue, any molecular structure that connects adjoining cells physically, chemically, or both at their plasma membranes.71
1107543746cell theoryAll organisms consist of one or more cells, the cell is the smallest unit of organization still displaying the properties of life, and life's continuity arises directly from growth and division of single cells.72
1107543747cell wallOf many cells (not animal cells), a semirigid but permeable structure that surrounds the plasma membrane; helps a cell retain its shape and resist rupturing.73
1107543748central vacuoleIn many mature, living plant cells, an organelle that stores amino acids, sugars, and some wastes; when it enlarges during growth, it forces the cell to enlarge and increase its surface area.74
1107543749centrioleA barrel-shaped structure that arises from a centrosome and organizes newly forming microtubules into a 9+2 array inside a cilium or flagellum.75
1107543750chloroplastsOrganelle of photosynthesis in plants and algae. Two outer membranes enclose a semifluid interior, the stroma. A third membrane forms a compartment inside that functions in ATP and NADPH formation; sugars form in the stroma.76
1107543751chromatinAll of the DNA molecules and associated proteins in a nucleus.77
1107543752chromosomesIn eukaryotic cells, a linear DNA double helix with many histones and other proteins attached. See also Bacterial chromosome78
1107543753cilium, ciliaA motile structure with a 9+2 array of microtubules that projects from the plasma membrane of certain eukaryotic cells. Modified cilia, such as those of hair cells, have sensory functions.79
1107543754cyanobacteriaA type of single-celled photoautotroph; the first to use a noncyclic pathway of photosynthesis, which slowly enriched the early atmosphere with oxygen.80
1107543755cytoplasmAll cell parts, particles, and semifluid substances between the plasma membrane and the nucleus or nucleoid.81
1107543756cytoskeletonIn a eukaryotic cell, the dynamic framework of diverse protein filaments that structurally support, organize, and move the cell and internal structures. Prokaryotic cells have a few similar protein filaments.82
1107543757endomembrane systemEndoplasmic reticulum, Golgi bodies, and transport vesicles concerned with modification of many new proteins, lipid assembly, and their transport within the cytoplasm or to the plasma membrane for export.83
1107543758endoplasmic reticulumER. Organelle that extends from the nuclear envelope through cytoplasm. Ribosomes coat the cytoplasmic side of rough ER, which modifes many new polypeptide chains in its lumen. Membrane lipids are assembled, fatty acids are broken down, and some toxins are inactivated in the lumen of smooth ER.84
1107543759endosymbiosisAn intimate, permanent ecological interaction in which one species lives and reproduces in the other's body to the benefit of one or both.85
1107543760flagellum, flagellaOf many eukaryotic cells, a long, whip-like motile structure with an inner 9+2 array of microtubules. Prokaryotic flagella do not have this array and are not whiplike; they rotate like a propeller.86
1107543761gap junctionsCylindrical arrays of proteins in the plasma membrane of adjoining cells; they pair up as open channels for rapid flows of ions and small molecules.87
1107543762Golgi bodiesOrganelle of endomembrane system; its enzymes modify many new polypeptide chains, assemble lipids, and package both inside vesicles for secretion or for use inside cell.88
1107543763intermediate filamentsCytoskeletal element that mechanically strengthens some cells.89
1107543764ligninGluelike polymer deposited in secondary cell walls; makes some plant parts stronger, more waterproof, and less vulnerable to attacks.90
1107543765lipid bilayerStructural basis of all cell membranes; mainly phospholipids arranged tail-to-tail in two layers, with hydrophilic heads of one dissolved in cytoplasmic fluid and heads of the other in extracellular fluid.91
1107543766lysosomeVesicle filled with enzymes that functions in intracellular digestion.92
1107543767microfilamentsThe thinnest cytoskeletal element; consists of actin subunits that function in cell contraction, movement, and structural support.93
1107543768microtubulesLargest cytoskeletal element; a filament of tubulin subunits. Contributes to cell shape, growth, and motion.94
1107543769motor proteinsA type of accessory protein that interacts with microfilaments or with microtubules to move cell structures or the whole cell; e.g., myosin.95
1107543770myosinAn ATP-energized motor protein that moves cell components on cytoskeletal tracks. Interacts with actin in sarcomeres to bring about contraction.96
1107543771nuclear envelopeA double membrane that is the outer boundary of the nucleus.97
1107543772nucleoidThe portion of a prokaryotic cell where DNA is physically organized but not enclosed in a membrane.98
1107543773nucleolusIn an interphase nucleus, a mass of material from which RNA and proteins are assembled into the subunits of ribosomes.99
1107543774nucleusLarge organelle with an outer envelope of two pore-ridden lipid bilayers that separates eukaryotic chromosomes from the cytoplasm.100
1107543775organellesOne of the membrane-bound compartments that carry out specialized metabolic functions in eukaryotic cells; e.g., a nucleus, mitochondria.101
1107543776peroxisomesEnzyme-filled vesicle that breaks down amino acids, fatty acids, and toxic substances such as ethanol.102
1107543777phospholipidA lipid with a phosphate group in its hydrophilic head. The main constituent of cell membranes.103
1107543778plasma membraneOuter cell membrane; the structural and functional boundary between cytoplasm and extracellular fluid.104
1107543779plasmodesma, plasmodesmataA plant cell junction that connects the cytoplasm of adjoining cells.105
1107543780primary wallThe first thin, pliable wall of young plant cells.106
1107543781prokaryotesA single-celled organism, often walled, that does not have the organelles characteristic of eukaryotic cells. Only bacteria and archaeans are prokaryotic.107
1107543782pseudopodsA dynamic lobe of membrane enclosed cytoplasm; functions in motility and phagocytosis by amoebas, amoeboid cells, and many white blood cells.108
1107543783ribosomesThe site of polypeptide chain synthesis in all cells. An intact one has two subunits of rRNA and proteins.109
1107543784secondary wallA rigid, permeable wall inside the primary wall of many plant cells; forms after the first growing season.110
1107543785stromaThe semifluid matrix between the thylakoid membrane system and two outer membranes of a chloroplast where sucrose, starch, cellulose, and other end products of photosynthesis are built.111
1107543786tight junctionsAn array of many strands of fibrous proteins collectively joining the sides of cells that make up an epithelium; the array prevents solutes from leaking between the cells.112
1107543787vesiclesA small, membrane-bound sac in the cytoplasm; different sacs transport or store substances or hold enzymes that digest their contents.113
1107543788active transportPumping of a specific solute across a cell membrane against its concentration gradient, through the interior of a transport protein. Requires energy input, as from ATP.114
1107543789adhesion proteinsOf multicelled species, a plasma membrane protein that helps cells stick together in tissues and to extracellular matrixes such as basement membrane.115
1107543790biofilmsLarge microbial populations that anchored themselves to epithelium, rocks, or other surfaces by their own secretions.116
1107543791bulk flowThe mass movement of one or more substances in the same direction, most often in response to pressure.117
1107543792calcium pumpActive transport protein; pumps calcium ions across a cell membrane against their concentration gradient.118
1107543793communication proteinsA membrane protein that helps form an open channel between the cytoplasm of adjoining cells.119
1107543794concentration gradientNet movement of like ions or molecules from a region where they are most concentrated to an adjoining region where they are less concentrated; they move down their concentration gradient.120
1107543795electric gradientA difference in electric charge between adjoining regions.121
1107543796endocytosisCell uptake of substances by forming vesicles from patches of plasma membrane. Three modes are receptor-mediated endocytosis, phagocytosis, and the bulk transport of extracellular fluid.122
1107543797exocytosisFusion of a cytoplasmic vesicle with the plasma membrane; as it becomes part of the membrane, its contents are released to extracellular fluid.123
1107543798fluid mosaic modelA cell membrane has a mixed composition (mosaic) of lipids and proteins, the interactions and motions of which impart fluidity to it.124
1107543799hydrostatic pressurePressure exerted by a volume of fluid against a cell wall, membrane, or some other structure that contains it; also called turgor pressure.125
1107543800hypertonic solutionOf two fluids, the one with the higher solute concentration.126
1107543801hypotonic solutionOf two fluids, the one with the lower solute concentration.127
1107543802isotonic solutionAny fluid having the same solute concentration as another fluid to which it is being compared.128
1107543803osmosisDiffusion of water across a selectively permeable membrane from a region where the water concentration is higher to a region where it is lower.129
1107543804osmotic pressureThe amount of pressure which, when applied to a hypertonic fluid, will stop osmosis from occurring across a semipermeable membrane.130
1107543805passive transportDiffusion of a solute across a cell membrane, through the interior of a transport protein.131
1107543806phagocytosis"Cell eating," a common endocytic pathway by which various cells engulf food bits, microbes, and cellular debris.132
1107543807pressure gradientDifference in pressure between two adjoining regions.133
1107543808recognition proteinsOne of a class of glycoproteins or glycolipids that project above the plasma membrane and that identify a cell as nonself (foreign) or self (belonging to one's own body tissue).134
1107543809selective permeabilityBuilt-in capacity of a cell membrane to prevent or allow specific substances from crossing it at certain times, in certain amounts.135
1107543810sodium-potassium pumpCotransporter that, when energized, actively transports sodium out of a cell and helps potassium passively diffuse into it at the same time.136
1107543811tonicityRelative solute concentrations of two fluids.137
1107543812transport proteinsMembrane protein that passively or actively assists specific ions or molecules into or out of a cell. The solutes move through the protein's interior.138

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