| Term | Definition |
|---|
| metabolism | involves processing nutrients to 1)transform energy to use for cellular work and 2)build cellular components. |
| universal property of cells | exchange with the environment. |
| metabolism | sum of all the chemical reactions of organism. |
| chemical reactions | occur at the cellular level; rearrangements of atoms. |
| catabolism | breaking down of complex molecules. (bonds broken, energy released) |
| anabolism | building of complex molecules from smaller components. (bonds formed, energy input) |
| exergonic reaction | bonds are broken, energy released. |
| endergonic reaction | bonds are formed, energy input. |
| metabolic pathway | series of chemical reactions. (2 types: anabolic/catabolic) |
| catalyst | any substance that increases the rate of a chemical reaction. |
| enzymes | organic catalysts utilized by biological systems to increase the rate of metabolic reactions. (made of protein) |
| specificity | enzymes exhibit to substrate and fit together like lock and key. |
| enzymes | neither reactants nor products of chemical reactions and not permanently altered by the reaction. |
| energy of activation | the initial amount of energy needed to start a chemical reaction. (barrier that prevents the reaction from proceeding) |
| enzymes | binding to substrate lowers the energy barrier and allows the reaction to proceed at a higher rate. |
| labile | enzymes are delicate and will unravel or change shape when exposed to harsh environmental conditions. (heat, pH, chemicals, radiation, etc.) |
| denaturation | results in loss of function; destroys metabolism and catalytic function. |
| optimal temperature | temperature in which enyzme can function. |
| simple enzyme | consists of protein only. |
| holoenzymes | conjugated enzymes that contain protein and nonprotein molecules. |
| apoenzyme | protein portion of holoenzyme. |
| cofactors | nonprotein portion of holoenzyme. (metallic cofactors or coenzymes) |
| metallic cofactors | inorganic molecules; minerals - iron, copper, magnesium. |
| coenzymes | organic molecules; vitamins. (derivative of NIACIN - NAD) |
| exoenzyme | breaks down large food molecules or harmful chemicals; breaks down host tissues, facilitates invasion. (transported extracellularly) |
| endoenzyme | internal metabolic functions; retained intracellularly. |
| exoenzymes | 1)cellulase 2)amylase 3)penicillinase 4)keratinase |
| endoenzymes | 1)catalase 2)oxidase 3)reductase |
| oxidase | adds electrons (and hydrogen) to oxygen. |
| reductase | reduces (ex. nitrate to nitrite) |
| catalase | breaks down hydrogen peroxide. |
| cellulase | degrades wood, converts to cellulose. |
| amylase | breaks down starch. |
| REDOX | oxidation reduction reaction. |
| polymerase | synthesis (ex. DNA) |
| proteinase, protease, peptidase | enzyme that hydrolizes peptide bonds of a protein. |
| lipase | digests fats and lipids. |
| virulence factors | the ability exoenzymes have to cause harm and contribute to pathogenicity. |
| 3 categories of virulence factors | 1)helping bacteria avoid host defense 2)assisting in invasion of tissues and promoting multiplication 3)toxic effect on host cells (exotoxins) |
| Streptococcus pyogenes (exoenzyme) | streptokinase - digests blood clots, helps invade wounds. |
| Pseudomonas aeruginosa (exoenzyme) | electase, collagenase - breakdown proteins in connective tissue and assist in invasion of tissues. |
| Clostridium perfringens (exoenzyme) | lipase - damages cell membranes, cell lysis and results in necrosis of tissues. |
| penicillinase | exoenzyme that inactivates penicillin. (example of virulence factor) |
| cellular respiration | catabolism of glucose. |
| reduction reaction | energy captured and transferred to ATP. |
| oxidation reaction | chemical energy released when bonds broken. |
| aerobic cellular respiration | oxygen is a reactant in the overall pathway and it functions as final electron acceptor. |
| anaerobic cellular respiration | uses inorganic molecule (not O2) (some bacteria use nitrate or sulfate) |
| fermentation | uses organic molecule in place of oxygen. |
| OILRIG | oxidation is lost; reduction is gained. |
| coenzymes | role is to capture and deliver electrons during REDOX. |
| NAD | coenzyme, carrier of electrons. (oxidized form after losing electron) |
| Oxygen | strongest oxidizing agent, picks up electrons. |
| cellular respiration | glucose + O2 --> 6 CO2 + H2O + ATP |
| cellular respiration | breaks down carbons as oxygen pulls electrons --> produces H2O + ATP |
| purpose of cellular respiration | 1)release energy 2)carbon made available |
| REDOX reactions | involved in extracting and harvesting energy from cellular fuel. |
| glycolysis | first stage of respiratory pathway in aerobic and anaerobic respiration and fermentation. |
| glycolysis | glucose is converted to pyruvate. |
| pyruvate | organic molecule used in fermentation. |
| pyruvate | converted to lactic acid (C3) or ethanol (C2 + CO2). |
| cellular respiration (Eukaryotes) | occurs in mitochondria. |
| glycolysis | occurs in cytoplasm, produces pyruvate. |
| oxidase | reduction reaction in which electrons are transferred O2 --> H2O. (ex. Pseudomonas- aerobe) |
| catalase | detoxifies H2O2 --> H2O + O2. (Staphylococcus is cat + ; Streptooccus, Enterococcus are cat -) |
| nitrate reductase | reduction reaction that transfers electrons NO3 --> NO2 + H2O . (ex. E. coli) |
| denitrification | further reduction to release N2 (nitrogen gas) (ex. Pseudomonas) |
| desulferase | some bacteria reduce SO4 to H2S. (proteus) |
| fermentation | alternate catabolic pathway utilized by some organisms in the absence of oxygen. |
| glycolysis | glucose + NAD+ + 2 ATP --> Pyruvate + NADH + 4ATP |
| fermentation pathway | NADH + Pyruvate --> NAD+ + ethanol + CO2 |
| fermentation | glucose is oxidized at higher rate, low yield. |
| glycolysis | produces 2 ATP. |
| Kreb's cycle | produces 2 ATP. |
| ETS | produces 32 to 34 ATP. |
| cellular respiration | altogether produces 36 to 38 ATP. (prokaryotes may be higher) |
| fermentation pathway | produces 2 ATP. |
| alcohol fermentation | ethanol and carbon dioxide are produced. (yeasts) |
| acid fermentation | yields organic acids. (homolactic or heterolactic) |
| homolactic | lactic acid only, bacteria like. (ex. Streptococcus, Lactobacillus - souring of milk - lactose is fermented) |
| heterolactic | lactic acid, acetic acid, CO2 - fermentation of glucose. |
| mixed acid fermentation | enzymes that can simultaneously produce many different acids. |
| enteric bacteria | produce intestinal gases. (CO2 and H2) |
| pyruvate | important metabolite, product of glycolysis, used to make many molecules - biosynthetic pathways. |
| regulation of enzymes | results in regulation of metabolism. |
| examples of regulation of metabolism | 1)enzyme activity may be blocked by competition for active site 2)enzymes may be switched on or off by regulatory molecules 3)enzyme production may be induced by substrate |
| constitutive enzyme | always present, produced in equal amounts or at equal rates, regardless of amount of substrate present. |
| regulated enzyme | not constantly present, production is turned on (induced) or turned off (repressed) in response to changes in concentration of the substrate. |
| feedback mechanisms | cause either induction or repression of synthesis of enzymes. |
| efficient use of energy | does not produce enzyme for which no substrate is available. |
| enzyme repression | build up of product represses enzyme synthesis. |
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