1. Microbial
Metabolism
Chapter 5 1

2. Metabolism Metabolism is all the chemical reactions to sustain life.
Metabolism = Catabolism + Anabolism
Driven by energy, ATP 2

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 life
B. fossil fuels
C. the sun
D. volcanic forces
E. 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, algae
Chemoautotroph - can make own food from CO2 using inorganic chemicals. ex. sulfur and nitrogen bacteria
Photoheterotroph - uses light for energy needs + organic source of C. ex. green and purple nonsulfur bacteria
Chemoheterotroph - uses chemicals for both energy and source of C.
ex. most organisms here -animals, fungi, bacteria, protozoa. 6

7. Groups based on metabolism7

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

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

10. Enzymes
Most CoEnzymes are VITAMINS. 10

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

12. Enzymes Catalytic Proteins
Re-useable - NOT consumed
Active site
“lock and key” function
The 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 bind
Functional 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. Anabolic
B. Catabolic 14

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. Anabolic
B. Catabolic 15

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

17. Glucose-6-phosphate + ADP
Enzyme Catalysis
Some reactions are reversible, some NOT.
1. Glucose + ATP
Glucose-6-phosphate + ADP
hexokinase
catalase
2. 2 H2O2
2 H2O + O2
ALL 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 of
glucose 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 activity
Once 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 functionality
Denature by:
heat, (think of cooked egg)
pH, (think of curdled milk)
solvents -alcohol, acetone, etc.
chemicals, oxidizers, aldehydes, etc 20

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

22. Inhibition of Metabolism
Sulfonamides
synthetic
Broad spectrum
Gram –
Bacteriostatic
Similar to PABA, inhibits folic acid formation. X 22

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.
STOPPED 23

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

25. ATP Nucleic acid base - adenine 5 carbon sugar - ribose
3 phosphate groups- aligned
2nd and 3rd bonds are high energy
Can add and remove phosphate groups 25

26. Ways to make ATP
Substrate 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.
Study 27

28. Glycolysis -EMP Glucose- 6C sugar Use 2 ATP to “kick-start”
Split into 2 3C molecules
Glyceraldehyde 3-phosphate
EMP~ Embden Meyerhof Parnas 28

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

30. Alternatives to Glycolysis
Pentose Phosphate
Makes pentoses for:
Nucleic acids
Some Amino acids
NADPH + ATP
Entner Doudoroff
2 NADPH + ATP
Used for biosynthesis 30

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 Acid
Substrate level phosphorylation. * 31

32. Electron Transport Chain* * *
cytochromes
Every NADH produces 3 ATP
Every FADH2 produces 2 ATP
Electrons passed from one cytochrome to another - each extracting energy.
Final electron acceptor is O2
End product is H2O.
* Oxidative phosphorylation. 32

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

34. ATP Synthase 34

35. Overall Reactions
Study 35

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 respiration
Fermentation
Pseudomonas
E. coli 38

39. Lipid Catabolism
Lipid 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, FADH2
They go to Electron Transport —> ATP. 39

40. Lipid Catabolism
Lipid 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, FADH2
They go to Electron Transport —> ATP. 40

41. Catabolism 41

42. Catabolism 42

43. Photophosphorylation
Sunlight excites chlorophyll
Energized 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 Carbohydrates45

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

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.
Reversible 48

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?
EMP
Bridging reaction
Krebs Cycle
Electron Transport
Pentose Phosphate
Entner Duodoroff
Calvin Benson
Beta Oxidation 51

52. THE END 52