Chapter 5 Microbial Metabolism Critical Thinking

Presentation on theme: "Microbial Metabolism Chapter 5 1."— Presentation transcript:

1 MicrobialMetabolismChapter 51

2 Metabolism Metabolism is all the chemical reactions to sustain life.
Metabolism = Catabolism + AnabolismDriven by energy, ATP2

3 Metabolism Metabolism = Catabolism + Anabolism Catabolism makes ATP.
Anabolism consumes ATP.Where does ALL this energy come from?3

4 REVIEW TIME IS UP !! 10 seconds left !!
Where does ALL energy on earth originate?A. plant lifeB. fossil fuelsC. the sunD. volcanic forcesE. it’s man made.TIME IS UP !!10 seconds left !!4

5 Groups based on metabolism
Autotroph1 - can make own food from CO2.Heterotroph - needs organic source of C.Phototroph - uses light for energy.Chemotroph- uses chemicals for energy.1 Troph means “to feed or to eat”.5

6 Groups based on metabolism
Photoautotroph - can make own food from CO using light. ex. plants, algaeChemoautotroph - can make own food from CO2 using inorganic chemicals. ex. sulfur and nitrogen bacteriaPhotoheterotroph - uses light for energy needs + organic source of C. ex. green and purple nonsulfur bacteriaChemoheterotroph - uses chemicals for both energy and source of C.ex. most organisms here -animals, fungi, bacteria, protozoa.6

7 Groups based on metabolism
7

8 Enzymes Catalytic PROTEINS Act ON Substrate(s)
Coenzymes (vitamins) accessory“lock and key” function~ structure8

9 Enzymes Act ON Substrate(s) Coenzymes (vitamins) accessory
“lock and key” function~ structure9

10 EnzymesMost CoEnzymes are VITAMINS.10

11 EnzymesCatalytic because they lower the activation energy required for a reaction to occur.11

12 Enzymes Catalytic Proteins
Re-useable - NOT consumedActive site“lock and key” functionThe turnover number is generally 1-10,000 molecules per second. Once they reach maximum rate, they won’t go higher.12

13 Enzymes Enzyme reactions : Both substrates must bind.
Any cofactors must bindFunctional group is moved with the aid of the cofactor.Both products are released.Enzyme free to catalyze another reaction.13

14 Enzymes Is this reaction catabolic or anabolic? A. Anabolic
Enzyme reactions :Condensation.Both substrates bind.Water is removed as molecules are covalently bound.Both products are released.Enzyme free to catalyze another reaction.Is this reaction catabolic or anabolic?A. AnabolicB. Catabolic14

15 Enzymes Is this reaction catabolic or anabolic? A. Anabolic
Enzyme reactions :Hydrolysis.Single substrate and H2O binds.Water is added as covalent bond is broken.Both products are released.Enzyme free to catalyze another reaction.Is this reaction catabolic or anabolic?A. AnabolicB. Catabolic15

16 EnzymesCartoon Vs. real molecular model. The groove in the model (left) is the “active site”.16

17 Glucose-6-phosphate + ADP
Enzyme CatalysisSome reactions are reversible, some NOT.1. Glucose + ATPGlucose-6-phosphate + ADPhexokinasecatalase2. 2 H2O22 H2O + O2ALL substrates must be present for reaction to occur.IF you have 5 µmoles of glucose and 10 µmoles of ATP,reaction #1 will proceed to produce 5 µmoles ofglucose 6-phosphate and then stop.17

18 Enzyme Catalysis Each enzyme has : Sometimes a set of inhibitors.
Optimum temperature.Optimum pH.Optimum [substrate] concentration.Sometimes a set of inhibitors.18

19 Enzyme Catalysis Optimum temperature
As temperature rises so does activityOnce you go over optimum, the rate decreases due to protein denaturation.19

20 Enzyme Denaturation Proteins have 3D structure (lock)
Destruction of 3D structure destroys functionalityDenature by:heat, (think of cooked egg)pH, (think of curdled milk)solvents -alcohol, acetone, etc.chemicals, oxidizers, aldehydes, etc20

21 Control of Enzymes Competitive Inhibitors ~similar to substrate.
Binds to Active site.Non-competitive (feedback) inhibitorUsually an end-product - binds to allosteric site.Gene expression - genetics (Chapter 7).21

22 Inhibition of Metabolism
SulfonamidessyntheticBroad spectrumGram –BacteriostaticSimilar to PABA, inhibits folic acid formation.X22

23 Feedback of Enzymes Occurs in a metabolic pathway
Pathway is usually anabolic.End products of pathway inhibit enzymes at the beginning (feedback).Prevent over- production.Conserve energy, resources.STOPPED23

24 Oxidation - Reduction Reduction- gain of electrons
Oxidation - loss of electronsMust have both.One chemical gains - one loses e-.24

25 ATP Nucleic acid base - adenine 5 carbon sugar - ribose
3 phosphate groups- aligned2nd and 3rd bonds are high energyCan add and remove phosphate groups25

26 Ways to make ATPSubstrate level - requires another high energy compound.Oxidative phosphorylation - uses high energy electrons.Photophosphorylation - uses light as energy source.26

27 Respiration vs Fermentation
In Fermentation NO oxygen present.Fermentation produces less ATP (2 vs 38 ).In Fermentation Carbon compound is the final electron acceptor, not O2.Study27

28 Glycolysis -EMP Glucose- 6C sugar Use 2 ATP to “kick-start”
Split into 2 3C moleculesGlyceraldehyde 3-phosphateEMP~ Embden Meyerhof Parnas28

29 Glycolysis -EMP Reduce NAD+ to NADH Make 2 ATP. Make high energy PEP
Make 2 more ATPNet Gain = 2 ATP*** Substrate level phosphorylation.29

30 Alternatives to Glycolysis
Pentose PhosphateMakes pentoses for:Nucleic acidsSome Amino acidsNADPH + ATPEntner Doudoroff2 NADPH + ATPUsed for biosynthesis30

31 Krebs (TCA) Cycle 2Pyruvate converted to 2AcetylCoA + 2 NADH
AcCoA condensed with oxalacetate (OAA) to make citric acid.Acids -decarboxylated to extract energy.Final product OAA.6 NADH made + 2 FADH2 + 2ATP + 4 CO2.Besides energy- acids used for carbon skeletons.TCA~TriCarboxylic AcidSubstrate level phosphorylation.*31

32 Electron Transport Chain
***cytochromesEvery NADH produces 3 ATPEvery FADH2 produces 2 ATPElectrons passed from one cytochrome to another - each extracting energy.Final electron acceptor is O2End product is H2O.* Oxidative phosphorylation.32

33 ATP Synthase ATP synthase imbedded in CM.
Protons transported across cell membraneChemiosmosisAs they pass back through, their energy makes ATP.33

34 ATP Synthase34

35 Overall ReactionsStudy35

36 Fermentation Glycolysis proceeds as usual. Pyruvic acid final product.
Pyruvate converted to other compounds to oxidize NADH to NAD+ so glycolysis can proceed.36

37 Fermentation Pyruvate converted to lactic acid.
Pyruvate converted to ethanol.MOST important NADH + H+ oxidized to NAD+Sometimes CO2 and other gases given off.makes bread rise,carbonates beer.37

38 Aerobic Respiration Vs. Fermentation
Aerobe - Glycolysis + Kreb’s + Electron Transport.Anaerobe - only glycolysis and fermentation.Facultative anaerobe - both.Aerobic respirationFermentationPseudomonasE. coli38

39 Lipid CatabolismLipid broken down to glycerol and fatty acids ~LIPASE (lie - pace).Glycerol enters EMP.Fatty acids broken down 2 C at a time to make AcCoA.AcCoA enters Kreb’s.Makes NADH, FADH2They go to Electron Transport —> ATP.39

40 Lipid CatabolismLipid broken down to glycerol and fatty acids ~LIPASE (lie - pace).Glycerol enters EMP.Fatty acids broken down 2 C at a time to make AcCoA.AcCoA enters Kreb’s.Makes NADH, FADH2They go to Electron Transport —> ATP.40

41 Catabolism41

42 Catabolism42

43 Photophosphorylation
Sunlight excites chlorophyllEnergized chlorophyll passes high energy electrons down electron transport.ATP made.43

44 Calvin Benson Cycle CO2 in.
Energy (ATP) from photophosphorylation used to make glucose from glyceraldehyde-3- phosphate.* REVERSE of Glycolysis*44

45 Synthesis of Carbohydrates
45

46 Synthesis of Lipids Glycerol from EMP. Fatty Acids from AcCoA.
Reverse Beta Oxidation46

47 Synthesis of Amino Acids
Acids from EMP, Krebs’ Cycle, and ED pathways are aminated.47

48 Transamination Amino group transferred from one compound to another.
Reversible48

49 Synthesis of Nucleotides
DO NOT Memorize.49

50 Integration of Metabolism
ALL pathways are interconnected !50

51 What to remember ? EVERYTHING ! (just kidding)
Basic characteristics of Enzymes & reactions.Major Pathways - purpose.Catabolic or anabolic ?How are they controlled?EMPBridging reactionKrebs CycleElectron TransportPentose PhosphateEntner DuodoroffCalvin BensonBeta Oxidation51

52 THE END52

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