Microbial Metabolism (Ch. 5) Before we start in on the details of metabolism you should make sure you understand the importance of enzymes and how they function. The following is a study guide. Enzymes: Why are they necessary? Speed of Reactions- Slow without help!!!! How do they work? (Explain)

Enzymes- proteins sometimes with a cofactor or coenzyme Cofactors- not organic: zinc, calcium, magnesium Coenzymes-organic NADH NADPH FMN FADH2 coenzyme a

Mechanism of Enzymatic Activity substrate + enzyme--› substrate enzyme complex--› products + enzyme substrate- the reactant(s) active site- where the substrate(s) bind to the enzyme induced fit- change in the shape of an enzyme when the substrate binds

Environment affects Enzymatic Activity (Explain how these factors affect enzyme activity) 1). Quantity of enzyme and substrate 2). Temperature 3). PH 5). inhibitors- inhibit the action of specific enzyme competitivenon-competitive or allosteric-

Feedback inhibition and Control of Metabolic Pathways: (Understand this!)

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Microbial Metabolism (Ch. 5) Metabolism- totality of an organism's chemical processes (manage the matter and energy resources ) energy- Ability to do work Cells work: living is work transport, movement, build complex chemicals, maintenance of order………………..

Metabolic pathways: anabolic pathways simple molecules are built into big, complex molecules consume energy, endergonic

catabolic pathways complex molecules are broken down into simpler ones release energy, exergonic

Energy Coupling-exergonic reactions drive endergonic reactions Role of ATP (adenosine triphosphate)?

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Energy Production: 1) ATP regeneration 2) Oxidation- Reduction Reactions 1) ATP regeneration: ADP + P → ATP

endergonic- requires energy

Three ways to regenerate ATP: 1) Substrate level phosphorylation- direct transfer of phosphate 2) Oxidative phosphorylation- energy is captured from chemicals (food) and used to add a phosphate to ADP 3) Photophosphorylation-energy from sunlight is used to add phosphate to ADP

2) Oxidation- Reduction Reactions (REDOX Reactions) Oxidation- loss of electrons Reduction- gain of electrons Remember- LEO the lion says GER

To determine who has been reduced: More negative charge or less positive (has more electrons!) Have more hydrogen(s)

Has less oxygen(s)

“Invisible”

Purpose of REDOX Reactions in cells: To capture and transfer energy Often use the captured energy to regenerate ATP

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Metabolic Diversity Among Organisms Classify by nutritional pattern: Energy source: phototrophs chemotrophs Carbon source: autotrophs heterotrophs

Catabolic processes: harvesting chemical energy aerobic respiration- The enzymatically controlled “burning’ of food with oxygen as one of the reactants. The complete oxidation of a “glucose” molecule. C6H12O6 + O6 ------> CO2 + H2O + energy

Three Parts to Aerobic Respiration: 1.) Glycolysis

2.) Krebs cycle

3.) Electron Transport Chain

Aerobic Respiration in total: C6H12O6 + O2 -------› CO2 + H2O + 36- 38 ATP + heat

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Anaerobic Respiration-Final electron acceptor is an inorganic compound but NOT O2 Many versions including: SO42→ H2S NO3- → NO2CO32-→ CH4

Less energy is recaptured as ATP

Fermentation- Partial Oxidation of a food molecule; results in an organic compound Many versions including: glucose → 2 pyruvate→

ethanol and CO2 lactic acid

Aerobic respiration, anaerobic respiration and fermentation compared: aerobic respiration: 36 to 38 ATP anaerobic: less than 36 more than 2 ATP fermention- 2 ATP Facultative anaerobes- both fermentation and aerobic respiration Examples?

Carbohydrates, fats, and proteins can all be used as fuel for cellular respiration. Feed into glycolysis and Krebs cycle need extracellular enzymes Carbohydrate polymers: fats: proteins:

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Anabolic processes: Building-up needed materials, Energy consuming Photosynthesis- make sugars Chemosynthesis-make sugars Polysaccharide Biosynthesis Lipid Biosynthesis Amino Acid and Protein synthesis Nucleotide Synthesis

Photosynthesis- - conversion of light energy into chemical bond energy (energy capture). Energy is used to reduce CO2 into organic compounds (anabolic process). Energy capture: Light reactions- Photophosphorylation Anabolic process: The Calvin Benson Cycle (Light Independent Reactions)

Oxygenic photosynthesis: H2O + CO2 + light energy → (CH2O)n + O2

Anyoxygenic Photosynthesis H2S + CO2 + light energy → (CH2O)n + S2

Chemosynthesis: using chemical energy to make sugars Organisms that make sugars then use some form of respiration to release the energy from the sugars.

Anabolic and Catabolic Processes are Interconnected:

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