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Metabolism of Microorganism

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Presentation on theme: "Metabolism of Microorganism"— Presentation transcript:

1 Metabolism of Microorganism

2 Why do we must know the metabolism of bacteria ?
Because we want to know how to inhibit or stop bacteria growth and want to control their metabolism to prolong shelf-life of food products.

3 Metabolism The Greek metabole, meaning change
Metabolism: all the biochemical reactions that take place in a cell Purpose: for reproduction more cellular components -

4 (lipid, protein, Carbohydrate) Cytoplasm (enzyme, ribosome, RNA)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Outer membrane (lipid, protein, Carbohydrate) Cytoplasm (enzyme, ribosome, RNA) Glycogen (carbohydrate) Nucleoid (DNA) Cell wall (peptidoglycan) Plasma Membrane(lipid, protein) Flagellum (protein) Pili (protein)

5 Tipe Metabolisme Anabolisme - biosintesis Katabolisme - degradasi
Pembentukan molekul komplek dari molekul yang sederhana Memerlukan energi (ATP) Katabolisme - degradasi Pemecahan molekul komplek menjadi molekul yang sederhana Menghasilkan energi (ATP)



8 Tasks of metabolic Bringing nutrients into the cell
Catabolism  convert nutrient into organic compound Biosynthesis  make small molecules from precursor metabolites Polymerization  monomer are chemically polymerized to produce macromolecules (protein, DNA, RNA, peptidoglycan, polysaccharides) Assembly  to assemble macromolecules into organel

9 What are nutrients that bacteria want?
C Sugar, Lipid Energy, Biosynthesis N Protein Biosynthesis O Air Energy

10 Nutrients transfer 1. Outer membrane
- Porins (protein) simple diffusion Only small molecules (not larger than trisaccharide) Concentration outside > inside cell 2. Cell wall 3. Cytoplasmic membrane Transporters  facilitated diffusion (active transport), pumping Concentration outside < inside cell

11 Catabolism Glucose  commonly used source of carbon and energy  catabolism Product  - 12 precursor metabolites (starting materials) - ATP, reducing power (energy)

12 METABOLISME perlu katalisator !!!!


14 Struktur Enzim Enzim sederhana – protein saja
Enzim konjugasi or holoenzim – protein dan nonprotein Apoenzim (bagian protein) Cofactor (bagian nonprotein) cofactor logam – besi, tembaga, magnesium coenzim - molekul organik - vitamin

15 Enzyme-substrate interactions

16 Enzim menurut lokasi kerja
Exoenzim – dikirim ke luar sel (extraseluler), memecah molekul makanan besar atau bahan kimia bahaya; selulase, amilase, penicillinase Endoenzim – tetap berada dalam sel, dan berfungsi di dalam sel.


18 Precursor metabolites by 3 pathway (central metabolism)
Glycolysis, 6 precursor metabolites TCA cycle (tricarboxylic acid), 4 precursor metabolites Pentose phosphate pathway, 2 precursor metabolites

19 Reducing power

20 Oxidation- Reduction Reactions
The production of ATP occurs by oxidation-reduction reactions Oxidation-reduction reactions: when one or more electrons are transferred from one substance to another

21 Figure 5.9

22 Oxidation-Reduction reactions
Oxidation: the loss of electrons Reduction: the gain of electrons Redox reactions: when both occur at the same time

23 Fe  Fe3+ + 3e- (teroksidasi  kehilangan 3 elektron) O2 + 4e-  O2- (tereduksi  mendapatkan 4 elektron)

24 When electrons removed from a compound protons often follow (H+)
Oxidation: loss of a hydrogen atom Reduction: gain of a hydrogen atom H+ + e-  H Proton Elektron Atom hidrogen

25 NAD(P)+ + 2H  NAD(P)H + H+
NADP teroksidasi NAD(P)H tereduksi : NAD(P)+ + 2H  NAD(P)H + H+

26 Stored Energy (ATP)

27 ATP Adenosine Triphosphate Energy currency of the cell
Releases free energy when it’s phosphate bonds are broken Allows cells to do work It takes work to stay alive Therefore, without ATP, there is no life

28 Using ATP for energy - 28

29 ATP formation Substrate-level Phosphorylation :
During glycolisis/Krebs cycle Adding single phosphate group to ADP PEP + ADP  pyruvate + ATP Oxidative phosphorylation/Chemiosmosis: by means of ATPase during respiration: uses an electrochemical or chemiosmotic gradient of protons (H+) across the inner mitochondrial membrane to generate ATP from ADP


31 Aerobic Respiration

32 Formula for Aerobic Respiration
C6H12O6 +6O CO2 + 6H2O +38 ATP

33 Steps of Aerobic Respiration
Glycolysis (glucose oxidation into pyruvate)  2 ATP Transition Step Krebs Cycle (convertion of pyruvate into CO2 & H2 in the presence of O2 or fermentation without O2)  2 ATP Electron Transport (hydrogen is oxidized by oxygen forming water)  34 ATP

34 Glycolysis Primary pathway used by nearly all organisms to convert glucose to pyruvate Contain 10 step pathway 1 molecule of glucose split into 2 molecules of pyruvate Generates 2 molecules of ATP and 2 molecules of NADH Glucose (6C) + 2NAD+ + 2ADP +2Pi  2 pyruvate (3C) + 2NADH + 2H+ + 2ATP


36 Glycolysis Net Yield of glycolysis: 2 ATP 2 NADH 2 pyruvate

37 Transition Step Links Glycolysis to Krebs Cycle
Pyruvate converted to acetyl Co-A NADH generated Net Yield of Transition Step: 2 NADH

38 Krebs Cycle 8 steps of Krebs cycle complete the oxidation of glucose
Incorporates the acetyl groups from transition step, releasing CO2 Does not directly use oxygen


40 TCA/Krebs Cycle Net Yield of Krebs Cycle: 1 ATP 3 NADH 1 NADPH 1 FADH2

41 Pentose Phosphate Pathway
Start with glucose 6-phosphate to phosphoglyceraldehyde Alternate route 2 precursor metabolites No ATP, 2 NADPH (oxidative phae) and Pentose (non-oxidative phase) Glucose 6-phosphate + 2 NADP+ + H2O → ribulose 5-phosphate + 2 NADPH + 2 H+ + CO2

42 The primary results of the Pathway are:
The generation of reducing equivalents, in the form of NADPH, used in reductive biosynthesis reactions within cells. (e.g. fatty acid synthesis) Production of ribose-5-phosphate (R5P), used in the synthesis of nucleotides and nucleic acids. Production of erythrose-4-phosphate (E4P), used in the synthesis of aromatic amino acids.


44 Electron transport system
Occurs in cell membrane Makes use of integral proteins called cytochromes, flavoproteins, quinones Series of Redox reactions Requires FADH2 and NADH O2 is final electron acceptor Water is final product ATP is produced via oxidative phosphorylation

45 Electron Transport Chain

46 Electron Transport Chain
As electrons fall from carrier to carrier, energy is used to form ATP This is done by pumping protons out of the cell as electrons move along This creates a proton gradient (proton motive force) Energy represented in this gradient used to synthesize ATP (ATP synthase is used)

47 Figure 5.16 (2 of 2)

48 Electron Transport Chain
Oxidative phosphorylation in electron transport chain yields: Each NADH generates 3 ATPs Each FADH2 generates 2 ATPs

49 Net ATP yield from Aerobic Respiration:
Glycolysis: 2 ATP, 2 NADH Transition Step: 2 NADH TCA cycle: 6 NADH, 2 FADH2, 2 ATP Electron Transport Chain: Add all NADH: 10 X 3= 30 Add all FADH2: 2 X 2=  38 ATP Add ATP from above = 4

50 Anaerobic Respiration
The same as aerobic respiration, generating ATP by phosphorylation, but uses inorganic molecule other than O2 , such as sulfate, nitrate, fumarate as terminal electron acceptor Anaerobic respiration produces less ATP than aerobic respiration

51 Fermentation Fermentation Produces ATP Using an Organic Electron Donors and Acceptors Fermentation is used when oxygen and other alternative electron acceptors are unavailable Generates 2 ATP by substrate level phosphorylation Also generates 2 NADH- must be recycled to NAD+ Different end products based on which microorganism

52 Products of fermentation

53 Lactic Acid Fermentation

54 Eukaryotes also perform fermentation, such as the yeast used in alcoholic fermentation to create alcoholic beverages

55 Regulation of Metabolism
Optimal amount of end products Only synthesized enzyme for the best available substrate Efficiency

56 Two major types of Metabolic Regulation
Genetic level  Regulation of gene expression (transcription)Regulates the amount of enzyme or protein Cellular levelRegulates enzyme activityallosteric proteins

57 Allosteric  different sites
Allosteric enzymes - Substrate site - Allosteric site  effector site (increase/decrease the rate of enzymatic reaction) Mechanism: change the conformation (shape) of enzyme influence the catalytic site


59 Negative Effectors

60 Positive Effectors


62 Feedback Inhibition (end-product inhibition)
End products (effector) bind the enzyme  inhibit the its catalytic activity A large amount of end products  synthesis slowed down A small amount of end products  synthesis speeds up



65 Cellular level- metabolic pathway controls through:
Isozymes A number of separate enzymes initially carry out the same conversion, each of which is sensitive to inhibition by a different end product.

66 The common pathway leading to the synthesis of the aromatic amino acids contains three isozymes. Each of these enzymes is specifically feedback-inhibited by one of the aromatic amino acids. Note how an excess of all three amino acids is required to completely shut off the synthesis of DAHP.

67 - Concerted feedback inhibition
More than one end product or all end products must be present in excess to repress the first enzyme.


69 - Sequential feedback inhibition
The common steps are inhibited by the product before the branch, and the first enzyme of each branch is inhibited by the branch product. High levels of P1 and P2 inhibit enzyme E3 and E4, respectively → M3 will accumulate →the pathway is inactivated if both P1 and P2 are high. M1 M2 M3 M4 M5 P1 P2 X E3 E1 E2 E4

70 Sequential Feedback Inhibition

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