Chapter 9 Cellular Respiration: Harvesting Chemical Energy Flashcards
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| 609139128 | catabolic pathways | metabolic pathways that release stored energy by breaking down complex molecules; do not directly move flagella, pump solutes across membranes, polymerize monomers, or perform other cellular work | |
| 609139129 | fermentation | Catabolic process; a partial degradation of sugars that occurs without the help of oxygen | |
| 609139130 | cellular respiration | the most prevalent and efficient catabolic pathway; oxygen is consumed as a reactant along with the organic fuel; mitochondria in eukayrotic cells; replenishes the ATP supply by powering the Phosphorylation of ADP | |
| 609139131 | triphosphate tail | on ATP; chemical equivalent of a loaded spring; the close packing of the three negatively charged phosphate groups is an unstable, energy-storing arrangement. releases energy by losing the terminal phosphate | |
| 609139132 | phosphorlylation | a compound that has had a transfer of a phosphate group from ATP to other compounds; primes a molecule to undergo some kind of change that performs work, and the molecule loses its phosphate group in the process | |
| 609139133 | Phosphate group transfer | the mechanism responsible for most types of cellular work; Enzymes shift a phosphate group from ATP to some other molecule, and this phosphorylated molecule undergoes a change that performs work ex-active transport and motor proteins | |
| 609139134 | oxidation reduction reactions (redox) | release energy stored in food molecules when electrons move closer to electronegative atoms, and this energy is used to synthesize ATP; transfer electrons or covalent sharing; in moving an electron from less elecneg. to more elecneg, chemical energy is released | |
| 609139135 | oxidation | the loss of electrons from one substance in a redox reaction | |
| 609139136 | reduction | the addition of electrons to another substance | |
| 609139137 | reducing agent | in a redox reaction, this substance is the electron donor (usually hydrogen) | |
| 609139138 | oxidizing agent | in a redox reaction, this substance is the electron acceptor; oxygen is best because its most electronegative | |
| 609139139 | burning | the rapid oxidation of fuel accompanied by an enormous release of energy as heat; activated when enzymes lower barrier of activation energy | |
| 609139140 | NAD+ (nicotinamide adenine dinucleotide) | coenzyme that functions as an oxidizing agent during respiration; electon acceptor; consists of two nucleotides joined together | |
| 609139141 | dehydrogenases | enzymes that remove a pair of hydrogen atoms from the substrate, a sugar or some other fuel; delivers these 2e's to NAD+ | |
| 609139142 | NADH | the reduced form of NAD+ that is electrically neutral; electrons transferred lose very little PE; represents stored energy that can be tapped to make ATP when the electrons complete their "fall" from NADH to oxygen | |
| 609139143 | Nicotinamide | a nitrogenous base not found in DNA or RNA | |
| 609139144 | ETC (electron transport chain) | of a number of molecules, mostly proteins, built into the inner membrane of a mitochondrion; accepts electrons from NADH and FADH2 and passes these electrons from one molecule to another; uses some of the released energy in a form that pumps H+ against its concentration gradient; rest released as heat; | |
| 609139145 | explosion | when oxygen captures the NADH electrons along with hydrogen nuclei to form water; an exergonic reacgition that releases a large amount of energy | |
| 609139146 | terminal electron accepter | oxygen; instead of explosive energy being released and wasted in a single explosive step, electrons cascade down the chain from one carrier molecule to the next, losing a small amount of energy with each step until they finally reach it; has a very great affinity for electrons and pulls them like gravity | |
| 609139147 | glycolysis | a metabolic process that breaks down glucose into 2 pyruvate molecules and release energy for the body in the form of ATP; occurs in cytosol; catabloic pathway; means "splitting of sugar,"; no CO2 is released | |
| 609139148 | pyruvate | Organic compound with a backbone of three carbon atoms. Two molecules form as end products of glycolysis; crosses the double membrane of the mitochondrion to enter the matrix, where the Krebs cycle decomposes it to carbon dioxide; the ionized form of a three-carbon acid | |
| 609139149 | NADH (or) FADH2 | transfers electrons from molecules undergoing glycolysis and the Krebs cycle to electron transport chains, which are built into the inner mitochondrial membrane | |
| 609139150 | Krebs cycle | in all plants and animals: enzymatic reactions in mitochondrial matrix after glycolysis involving oxidative metabolism of acetyl compounds to produce high-energy phosphate compounds; catabolic pathway; releases less than 1/4 of the chemical energy stored in glucose | |
| 609139152 | oxidative phosphorylation | The mode of ATP synthesis where energy released at each step of the ETC is stored in a form the mitochondrion can use to make ATP; powered by the redox reactions that transfer electrons from food to oxygen; occurs in the inner membrane of the mitochondrion ; accounts for almost 90% of the ATP generated by respiration | |
| 609139154 | substrate-level phosphorylation | mechanism in a few of the reactions of glycolysis and the krebs cycle where A smaller amount of ATP is directly formed This mode of ATP synthesis occurs when an enzyme transfers a phosphate group from a Bsubstrate molecule to ADP | |
| 609139156 | Bsubstrate molecule | an organic molecule generated during the catabolism of glucose | |
| 609139158 | phosphoenolpyruvate | Some ATP is made by direct enzymatic transfer of a phosphate group from a this phosphate donor to ADP; formed from the breakdown of sugar during glycolysis | |
| 609139159 | glucose | a six-carbon sugar; split into two three-carbon sugars that are then oxidized and their remaining atoms rearranged to form two molecules of pyruvate | |
| 609139160 | pyruvic acid | three carbon acid that is inoized into pyruvate | |
| 609139161 | junction step | step between Glycolysis and Krebs cycle; upon entering the mitochondrion, pyruvate is first converted to a compound called acetyl coenzyme A, or acetyl CoA | |
| 609139162 | Chemiosmosis | the ETC makes no ATP directly, so the mitochondrion couples ETC and energy release to ATP synthesis with this mechanism;the process where an H+ gradient across a membrane couples the redox reactions of the electron transport chain to ATP synthesis | |
| 609139163 | ATP synthase | resides in mitochondrial and chloroplast membranes of eukaryotes and in plasma membranes of prokaryotes; synthase uses the energy of an existing ion gradient to phosphorylate ADP to ATP; its power is a difference in the concentration of H+ (PH) on opposite sides of the inner mitochondrial membrane pumped by ETC; has three main parts: a rotor, a rod, and a knob; oxidative | |
| 609139164 | cylindrical rotor | hydrogen ions flow through this down their gradient and cause the attatched rod to rotate a stream to a watermill | |
| 609139165 | knob | portrudes into the mitochondrial matrix; spinnig rod changes this and activates catalytic sites where ADP and inorganic phosphate combine to make ATP | |
| 609139166 | proton motive force | The potential energy stored in the form of an electrochemical gradient, generated by the pumping of hydrogen ions across biological membranes during chemiosmosis. | |
| 609139167 | Fermentation | an extension of glycolysis that can generate ATP solely by substrate-level phosphorylation -- as long as there is a sufficient supply of NAD+ to accept electrons during the oxidation step of glycolysis | |
| 609139168 | Anaerobic catabolism | glucose is broken down in the absence of oxygen in the cytoplasm through a series of chemical reactions, first into pyruvic acid and then into lactic acid; fermentation | |
| 609139169 | aerobic catabolism | NAD+ is recycled productively from NADH by the transfer of electrons to the electron transport chain | |
| 609139170 | alcoholic fermentation | releases carbon dioxide from the pyruvate, which is converted to the two-carbon compound acetaldehyde; acetaldehyde is then reduced by NADH to ethanol. This regenerates the supply of NAD+ needed for glycolysis. ex- yeast | |
| 609139171 | lactic acid fermentation | pyruvate is reduced directly by NADH to form lactate as a waste product, with no release of CO2 | |
| 609139172 | lactate | ionized form of lactic acid; accumulates and causes fatigue and pain, but is taken from blood to liver and converted back to pyruvate by liver cells | |
| 609139173 | facultative anaerobes | organisms, including yeasts and many bacteria, can make enough ATP to survive using either fermentation or respiration; also our muscles function as these on the cellular level | |
| 609139174 | deamination | to use excess proteins in body for cellular respiration, their ammino groups are removed in this process; the nitrogen base is secreated as urea or ammonia | |
| 609139175 | beta oxidation | a metabolic sequence that breaks the fatty acids down to two-carbon fragments, which enter the Krebs cycle as acetyl CoA | |
| 609139176 | phosphofructokinase | pacemaker of cell respiration; It is stimulated by AMP , but it is inhibited by ATP and by citrate |