Chapter 5 Vocabulary Test Questions – Flashcards
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| Activation energy |
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| The energy required to start a chemical reaction |
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| Active site |
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| Area on the surface of an enzyme to which its substrate binds |
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| Aerobe |
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| An organism that uses oxygen |
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| Aerobic respiration |
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| Process in which aerobic organisms gain energy from the catabolism of organic molecules via the Krebs cycle and oxidative phosphorylation |
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| Alcoholic fermentation |
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| Fermentation in which pyruvic acid is reduced to ethyl alcohol by electrons from reduced NAD (NADH) |
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| Allosteric site |
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| The site at which a noncompetitive inhibitor binds |
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| Amphibolic pathway |
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| A metabolic pathway that can yield either energy or building blocks for synthetic reactions |
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| Anabolic pathway |
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| A chain of chemical reactions in which energy is used to synthesize biologically important molecules |
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| Anabolism |
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| Chemical reactions in which energy is used to synthesize large molecules from simpler components (also called synthesis) |
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| Anaerobe |
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| An organism that does not use oxygen, includes the organisms killed by exposure to oxygen |
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| Anaerobic respiration |
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| Respiration in which the final electron acceptor in the electron transport chain is an inorganic molecule other than oxygen (i.e., a sulfate or nitrate) |
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| Apoenzyme |
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| The protein portion of an enzyme that MUST combine with a nonprotein coenzyme or cofactor to form an active holoenzyme |
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| Autotrophs |
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| Organisms that can get their carbon from inorganic sources and manufacture their own nutrition (self-feeding) via photosynthesis or inorganic chemicals |
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| Autotrophy |
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| The classification of organisms that are able to obtain their nutrition and carbon via self-feeding methods (i.e. photosynthesis and from carbon dioxide) |
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| Beta oxidation |
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| A metabolic pathway that breaks down fatty acids into 2-carbon pieces |
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| Catabolic pathway |
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| A chain of chemical reactions that capture energy by breaking down large molecules into simpler components |
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| Catabolism |
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| The chemical breakdown of molecules in which energy is released |
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| Chemical equilibrium |
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| A steady state in which there is no net change in the concentrations of substrates or products |
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| Chemiosmosis |
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| Chemoautotroph |
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| An autotroph that obtains energy by oxidizing simple inorganic substances such as sulfides and nitrites |
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| Chemoheterotroph |
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| A heterotroph that obtains energy from breaking down ready made organic molecules |
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| Citric acid cycle |
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| Coenzyme |
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| A nonprotein organic molecule bound to or loosely associated with an enzyme. Â Many are synthesized from vitamins, essential nutrients that are required to make coenzymes |
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| Cofactor |
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| Usually an inorganic ion that improve the fit of an enzyme with its substrate. Â Examples include: magnesium, zinc, manganese. Â They can be essential in allowing the reaction to proceed. |
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| Competitive inhibitor |
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| A substrate-like molecule that can bind to the active site of an enzyme while making the enzyme unable to perform any of its actions |
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| Cyclic photophosphorylation |
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| Cytochrome |
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| Electron acceptor |
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| AKA oxidizing agent because by accepting the electron it is causing another molecule to be oxidized, yet this causes the electron acceptor to be reduced. |
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| Electron donor |
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| AKA reducing agent because when it gives up an election it's causing another molecule to be reduced while at the same time causing itself to be oxidized. |
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| Electron transport |
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| Electron transport chain |
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| Endoenzyme |
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| Intracellular enzymes |
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| Enzyme |
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A special category of proteins found in all living organisms that act as catalysts to speed up biochemical reactions without raising body temperature to levels unconducive  to life |
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| Enzyme-substrate complex |
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| What forms when a substance collides with the active site of its specified enzyme. Â This weakens the chemical bonds in the substrate. |
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| Exoenzyme |
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| Extracellular enzymes are synthesized in the cell but cross the cell membrane to act in the periplasmic space or in the cell's immediate environment |
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| FAD |
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| Feedback inhibition |
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| A reversible noncompetitive inhibition that regulates the rate of many metabolic pathways, i.e. when the end product of a pathway accumulates and then binds to and inactivates the enzyme that catalyzed the first reaction in the pathway. |
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| Fermentation |
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| One process by which pyruvic acid is metabolized in the absence of oxygen. Â It is the result of having to recycle limited amount of NAD by passing the electrons of reduced NAD off to other molecules. Two types: homolactic acid fermentation and alcoholic fermentation - does NOT capture energy in ATP from the metabolism of pyruvic acid |
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| Flavoprotein |
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| Glycolysis |
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| glyco (sugar)-lysis(splitting) means to split the sugar.  Does NOT require oxygen but can take place in the presence of oxygen AKA the Embden-Meyerhof pathway is the metabolic pathway used by most autotrophic and heterotrophic organisms whether or not they are anaerobes or aerobic to break down glucose for energy |
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| Heterotrophy |
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| "Other feeding" the use of carbon atoms from organic compounds for the synthesis of biomolecules |
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| Heterotrophy |
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| Holoenzyme |
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| A functional enzyme consisting of an apoenzyme and a coenzyme or a cofactor |
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| Homolactic acid fermentation |
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| Simplest pathway for pyruvic acid metabolism in which only lactic acid is made using electrons from reduced NAD. Â Produces NO gas. Â Some organisms that use this are used to make cheese |
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| Krebs cycle |
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| Light-dependent reactions |
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| Light-independent reactions |
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| Metabolic pathway |
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| A series of chemical reactions in which the product of one reaction serves as a substrate for the next: A -> B -> C -> D -> E, and so on. A = initial substrate, E = final product, and B, C, and D are intermediates |
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| Metabolism |
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| The sum of all the chemical processes carried out by living organisms |
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| NAD |
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| Noncompetitive inhibitor |
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| Substances that can attach to the enzyme at its allosteric site thereby distorting the tertiary protein structure and alter the shape of the active site making the true substrate unable to attach to the enzyme and thereby inhibiting the enzyme |
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| Noncyclic photoreduction |
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| Oxidation |
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| The loss or removal of an electron, yet oxygen need not be present if another electron acceptor is available |
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| Oxidative phosphorylation |
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| Permease |
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| Phosphorylation |
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| The addition of a phosphate group to a molecule, often from ATP to increase the molecule's energy thus this serves as energy carriers in biochemical reactions |
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| Phosphotransferase system |
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| Photoautotroph |
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| An autotroph that obtains energy from light |
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| Photoheterotroph |
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| Â A heterotroph that obtains energy from light |
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| Photolysis |
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| Photosynthesis |
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| Porin |
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| Quinone |
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| Reduction |
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| The gain of electrons |
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| Redox reactions |
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| Due to oxidation and reduction often occur simultaneously the reactions between them are called redox reactions |
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| Subtrate |
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| The substance on which an enzyme acts in order to produce a chemical reaction so that a specific product may be produced |
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| Carrier molecule |
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| Carry hydrogen atoms or electrons in many oxidative reactions |
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Optimum temperature and Optimum pH |
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| The temperature and pH at which an enzyme functions at its best, meaning when it catalyzes a reaction most rapidly. Â Changes in temperature or pH affect the enzyme activity (the rate at which an enzyme catalyzes a reaction) |
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| Four events of the glycolysis pathway |
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1. Substate-level phosphorylation 2. Breaking of a six-carbon molecule (glucose) into two three-carbon molecules 3. The transfer of two electrons to the coenzyme NAD 4. The capture of energy into ATP |
