Microbial Metabolism

Microbial Metabolism - chapter 8

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