《微生物学》课程教学课件（PPT讲稿）chapter 7 metablism1

Chapter/ Microbial metablism Catabolism anabolism Fermentation Respiration Nitrogen fixtation The synthesis of peptiglydogen

Chapter7 Microbial metablism Catabolism, anabolism Fermentation Respiration Nitrogen fixtation The synthesis of peptiglydogen

7.1 An overview of metabolism Metabolism may be divided into two major parts: catabolism and anabolism Catabolism: larger and more Waste products complex molecules are broken Nutrients for Biosynthesis down into smaller, simpler molecules with the release of Energy ehergy S Energy Anabolism: the synthesis of complex molecules from simpler ones with the input of energy E Igy sonce

7.1 An overview of metabolism • Metabolism may be divided into two major parts: catabolism and anabolism. • Catabolism: larger and more complex molecules are broken down into smaller, simpler molecules with the release of energy. • Anabolism: the synthesis of complex molecules from simpler ones with the input of energy

Amino acids Monosaccharides TThe Stage 2 NADH three stages AcotyI-CoA of ATP catabolism FADH Tricarboxylic acid cycle Electron Cytochromes Figure 9.3 The Three Stages of Catabolism. A general diagram of aerobic catabolism in a chemoorganoheterotroph showing the three stages in this process and the central position of the tricarboxylic acid cycle. Although there are many different proteins, polysaccharides, and lipids, they are degraded through the ctivity of a few common metabolic pathways. The dashed lines show the flow of electrons, carried by NADH and FADH2. to the electron transport chain

The three stages of catabolism

7.2 Fermentation The Embden-Meyerhof Pathway a fermentation is an internally balanced oXidation-reduction reaction in which some atoms of the energy source(electron donor become more reduced whereas others become more oxidized, and energy is produced by substrate-level phosphorylation

7.2 Fermentation : The Embden-Meyerhof Pathway A fermentation is an internally balanced oxidation-reduction reaction in which some atoms of the energy source (electron donor) become more reduced whereas others become more oxidized, and energy is produced by substrate-level phosphorylation

ADP (a) Substrate-level phosphorylation Energized membrane 子++十十十十十十+ ADP P Less energized membrane (b) Oxidative phosphorylation Energy conservation in fermentation and respiration

Energy conservation in fermentation and respiration

Embden-Meyerhof pathway Glycolysis: A common biochemical pathway for the fermentation of glucose is glycolysis, also named the Embden-Meyerhof pathway for its major discoverers. Can be divided into three major stages Stage I: A series of preparatory rearrangements: reactions that do not involve oxidation -reduction and do not release energy but that lead to the production from glucose of two molecules of the key intermediate, glyceraldehyde 3 phosphate Stage I: Oxidation-reduction occurs, energy is conserved in the form of aTP, and two molecules of pyruvate are formed Stage Il: A second oxidation-reduction reaction occurs and fermentation products(for example, ethanol and co2 or lactic acid)are formed

Embden-Meyerhof pathway Glycolysis: A common biochemical pathway for the fermentation of glucose is glycolysis, also named the Embden-Meyerhof pathway for its major discoverers. Can be divided into three major stages. Stage I : A series of preparatory rearrangements: reactions that do not involve oxidation-reduction and do not release energy but that lead to the production from glucose of two molecules of the key intermediate, glyceraldehyde 3- phosphate. Stage II: Oxidation-reduction occurs, energy is conserved in the form of ATP, and two molecules of pyruvate are formed. Stage III: A second oxidation-reduction reaction occurs and fermentation products (for example, ethanol and CO2, or lactic acid) are formed

NADH Lactate Pyruvate NADH Acetaldehyde Ethanol pyruvate co Oxaloacetate acetolactate NADH Acetyl-C。A Form Co NADH H co Malate Acetyl-(P)Acetaldehyde Acetoin HO 上烨P~叫 NADH Acetate Ethanol Fumarate 2. 3-butanediol Acetoacetyl-CoA NADH co Succinate Acetone Butyryl-c。A NADH NADH c。A 。 Co Butyraldehyde Butyryl-OP NADH Propionate Isopropanol Butanol Butyrate 1.Lactic acid bacteria (Streptococcus, Lactobacilus), Bacillus 2. Yeast,zym。 nonas 3. Propionic acid bacteria (Propionibacterium) 4. Enterobacter, serratia, Bacilus 5. Enteric bacteria(Escherichia, Enterobacter, salmonella, Proteus) 6. Clostridium

Three type fermentation of Saccharomyces cerevisiae I: pyruvate>acetaldehyde>ethanol II: pH7: glycerol Ill: NaHSO3

Three type fermentation of Saccharomyces cerevisiae I: pyruvate→acetaldehyde→ethanol II: pH7: glycerol III: NaHSO3

Lactic acid fermentation The reduction of pyruvate to lactate Homofermentative(同型发酵的) group: produces only lactic acid as sole pl roduct Heterofermentatiⅳve(异型发酵的 group: produces ethanol, CO2 and lactic acid

Lactic acid fermentation • The reduction of pyruvate to lactate • Homofermentative（同型发酵的） group: produces only lactic acid as sole product • Heterofermentative（异型发酵的） group: produces ethanol, CO2 and lactic acid

6.6 Respiration and Electron Transport Respiration: in which molecular oxygen or some other oxidant serves as the terminal electron acceptor The discussion of respiration deals with both the carbon and electron transformations (1) the biochemical pathways involved in the transformation of organic carbon to CO2 (2) the way electrons are transferred from the organic compound to the terminal electron acceptor, driving ATP synthesis at the expense of the proton motive force

6.6 Respiration and Electron Transport The discussion of respiration deals with both the carbon and electron transformations: • (1) the biochemical pathways involved in the transformation of organic carbon to CO2. • (2) the way electrons are transferred from the organic compound to the terminal electron acceptor, driving ATP synthesis at the expense of the proton motive force. Respiration : in which molecular oxygen or some other oxidant serves as the terminal electron acceptor