Bio 171 Ch 8, 9, 10

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Question Answer
Activation energyThe amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation.
ADPAbbreviation for adenosine diphosphate, a nucleotide essential in photosynthesis and glycolysis.
aerobic respirationA form of cellular respiration that requires oxygen in order to generate energy.
anaerobic respirationA form of respiration using electron acceptors other than oxygen. Although oxygen is not used as the final electron acceptor, the process still uses a respiratory electron transport chain; it is respiration without oxygen.
Alcoholan organic compound in which the hydroxyl functional group (-OH) is bound to a carbon atom. This carbon center should be saturated, having single bonds to three other atoms.
Alcohol fermentationGlycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD+ and releasing carbon dioxide.
AMPAbbreviation for adenosine monophosphate.
Anabolism(from Greek: ανά "upward" and βάλλειν "to throw") is the set of metabolic pathways that construct molecules from smaller units. These reactions require energy. One way of categorizing metabolic processes, whether at the cellular, organ or organism level is as "anabolic" or as "catabolic", which is the opposite. Anabolism is powered by catabolism, where large molecules are broken down into smaller parts and then used up in respiration. Many anabolic processes are powered by the hydrolysis of adenosine triphosphate (ATP).
Autotrophs or producersOrganisms that are capable of sustaining life without relying on materials produced by other living systems.
ATPAn adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolized. This energy is used to drive endergonic reactions in cells.
C3 plantA plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate.
C4 plantA plant in which the Calvin cycle is preceded by reactions that incorporate CO2 into a four-carbon compound, the end product of which supplies CO2 for the Calvin cycle.
Calvin Cycle/Calvin Benson CycleThe second of two major stages in photosynthesis (following light reactions), involving fixation of atmospheric CO2 and reduction of the fixed carbon into carbohydrate.
CAM plantsA plant that utilizes the Crassulacean acid metabolism (CAM) as an adaptation for arid conditions. CO2 entering the stomata during the night is converted into organic acids, which release CO2 for the Calvin Cycle during the day, when the stomata are closed.
Catabolic pathwayA sequence of degradative chemical reactions that break down complex molecules into smaller units, usually releasing energy in the process.
Catabolic reactionA metabolic pathway that releases energy by breaking down complex molecules to simpler molecules.
CelluloseA structural polysaccharide of plant cell walls, consisting of flucose monomers joined by ß glycosidic linkages.
Chemical SpecificityThe ability of a protein's binding site to bind specific ligands. The fewer ligands a protein can bind, the greater its specificity.
ChemiomosisAn 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 ___________.
ChemoautotrophsRely on reductive potential of their environment to build organic molecules.
Citric acid cycleA chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules begun in glycolysis by oxidizing acetyl CoA (derived from pyruvate) 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.
CO2A naturally occurring chemical compound composed of two oxygen atoms each covalently double bonded to a single carbon atom.
CoenzymeAn organic molecule serving as a cofactor. Most vitamins function as coenzymes in metabolic reactions.
Coenzyme AA coenzyme, notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle.
Cofactorsmolecules that bind to enzymes and are required for normal enzyme activity. May be permanently bound by the enzyme or reversibly bound.
Condensation reactionAlso commonly referred to as dehydration synthesis, it is a chemical reaction in which two molecules or moieties (functional groups) combine to form a larger molecule, together with the loss of a small molecule. Possible small molecules lost are water, hydrogen chloride, methanol, or acetic acid.
Cyclic phosphorylationIn cyclic electron flow, the electron begins in a pigment complex called photosystem I, passes from the primary acceptor to ferredoxin, then to cytochrome b6f (a similar complex to that found in mitochondria), and then to plastocyanin before returning to chlorophyll. This transport chain produces a proton-motive force, pumping H+ ions across the membrane; this produces a concentration gradient that can be used to power ATP synthase during chemiosmosis.
Electron Transport Chain or System (ETS)A sequence of electron carrier molecules (membrane proteins) that shuttle electrons down a series of redox reactions that release energy used to make ATP.
ElectronegativityThe attraction of a given atom for the electrons of a covalent bond.
Electronegative energyThe tendency of electrons to move from one atom or molecule to another.
EndergonicReactions that absorb energy.
ExergonicReactions that release energy. A spontaneous chemical reaction in which there is a net release of free energy.
Exergonic reactionA nonspontaneous chemical reaction, in which free energy is absorbed from the surroundings.
EndothermicReferring to organisms that are warmed by heat generated by their own metabolism. This heat usually maintains a relatively stable body temperature higher than that of the external environment.
Exothermic("outside heating") describes a process or reaction that releases energy from the system, usually in the form of heat
Engleman's Experiement
FAD+A derivative of riboflavin that functions in certain oxidation-reduction reactions in the body as a coenzyme of various flavoproteins.
FADH2The reduced form of flavin adenine dinucleotide.
FermentationA 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.
First Law of ThermodynamicsEnergy changes location and form, but is not created or destroyed.
Free EnergyThe 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 (delta G) is calculated by the equation delta G = delta H - T delta S, where delta H is the change in enthalpy (in biological systems, equivalent to total energy), T is the absolute temperature, and delta S is the change in entropy.
G3P (glyceraldehyde 3-phosphate)A three-carbon carbohydrate that is the direct product of the Calvin cycle; it is also an intermediate in glycolysis.
GlycolysisA series of reactions that ultimately splits glucose into pyruvate. __________ occurs in almost all living cells, serving as the starting point for fermentation or cellular respiration.
Gradient energyThe tendency of molecules to move down their concentration gradient.
Heterotrophs or consumersOrganisms that rely on organic molecules that have been produced by other living systems for their energy.
Hydration reaction
Hydrogen bondA type of weak chemical bond that is formed when the slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule or in another region of the same molecule.
HydrolysisA chemical reaction that breaks bonds between two molecules by the addition of water; functions in disassembly of polymers to monomers.
Hydrolysis reaction
HydrophilicHaving an affinity for water.
Krebs Cycle
Lactic acid
Lactic acid fermentationGlycolysis followed by the reduction of pyruvate to lactate, regenerating NAD+ with no release of carbon dioxide.
Law of Thermodynamics
Light energy (photosynthesis)Can be absorbed by electrons and allow them to move to less electronegative substances.
Light dependent reactionThe light reactions use light energyto energize electrons. The energy in the electrons is then used to create a proton gradient, then the electrons are harvested and sent to the light independent reactions. The proton gradient is used to make ATP, which is also sent to the light independent reactions. The light dependent reactions: Use the water that is consumed in the photosynthetic chemical reaction.
Light independent reaction_____ ___________ reactions use ATP and electrons from the light dependent reactions to create chains of carbon that are 3 carbons long. This 3-carbon chain is used as a starting point to make a wide variety of subunits for macromolecules (carbohydrates, lipids, amino acids and nucleotides) and thus indirectly enables the plant to make macromolecules such as lipids, polysaccharides, proteins and nucleic acids. The dark reactions:
Light reactionThe first of two major stages in photosynthesis (preceding the Calvin cycle). These reactions, which occur on the thylakoid membranes of the chloroplast or on membranes of certain prokaryotes, convert solar energy to the chemical energy of ATP and NADPH, releasing oxygen in the process. Produce two 3-carbon sugars that are combined to form glucose at a product of the photosynthetic chemical reactions.
LipidAny of a group of large biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water.
MaltoseA disaccharide of glucose formed by the enzymic hydrolysis of starch: used in bacteriological culture media and as a nutrient in infant feeding.
MetabolismThe totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism.
NAD+Nicotinamide adenine dinucleotide, a coenzyme that cycles easily between oxidized (____) and reduced (NADH) states, thus acting as an electron carrier.
NADHThe reduced form of nicotinamide adenine dinucleotide.
NADPHNicotinamide adenine dinucleotide phosphate, an electron acceptor that temporarily stores energized electrons produced during the light reactions.
Nucleic acidsA polymer (polynucleotide) consisting of many nucleotide monomers; serves as a blueprint for proteins and, through the actions of proteins, for all cellular activities. The two types as DNA and RNA.
NucleotideThe building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.
OxidationThe complete or partial loss of electrons from a substance involved in a redox reaction.
ReductionAny of a class of chemical reactions in which the number of electrons associated with an atom or group of atoms is increased. The electrons taken up by the substance reduced are supplied by another substance, often hydrogen (H), which is thereby oxidized.
Oxidative phosphorylationThe production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.
Peptide bondThe covalent bond between the carboxyl group on one amino acid and the dehydration reaction.
Photoautotrophs Rely on light to provide the energy that they need to build organic molecules.
PGALAcronym for Phosphoglyceraldehyde, a chemical compound that serves as an intermediate in several central metabolic pathways in all organisms.
PhosphofructokinaseAn important enzyme in virtually all living cells. It performs the committed step in the glycolytic pathway, namely, the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate.
Phosphofrucktokinase regulationVarious molecules that indicate the metabolic needs of the cell affect the activity of enzymes. Because PFK is involved in a very important metabolic step, it is heavily regulated by a number of small molecules that are involved in energy metabolism. These molecules include high-energy metabolic intermediates such as phosphoenolpyruvate (PEP), which inhibits the activity of PFK. This makes sense because high levels of PEP indicate a sufficient cellular energy supply. Intermediates such as adenosine diphosphate (ADP), which indicate a need for cellular energy, activate PFK.
PhotophosphorylationThe process of generating ATP from ADP and phosphate by means of chemiomosis, 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.
PhotosynthesisThe conversion of light energy to chemical energy that is stored in sugars or other organic compounds.
P (subscript) i
Positional energyThe tendency of closely positioned atoms with the same charge to repel each other.
PyruvateThe end product of gylcolysis. In anaerobic respiration, ________ is used as the starting point for fermentation, yielding either ethanol or lactate.
Redox reactionA chemical reaction involving the complete or partial transfer of one or more electrons from one reactant to another; short for REDuction-OXidation reaction.
Cellular respirationThe set of the metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.
RubiscoRibulose biphosphate (RuBP) carboxylase, the enzyme that catalyzes the first step of the Calvin cycle (the addition of CO2 to RuBP).
Second Law of ThermodynamicsWhen energy changes form, energy is lost.
StarchA storage polysaccharide in plants, consisting entirely of glucose monomers joined by _a_ glycosidic linkages.
SomaThe cell body.
Substrate-level phosphorylationThe enzyme-catalyzed formation of ATP by direct transfer of a phosphate group to ADP from an intermediate substrate in catabolism.
Three main stages of respirationGlycolysis, the Krebs Cycle and the Electron Transport Chain.