Metabolism Catabolism-Glycolysis (Kreb Cycle

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Metabolism

• Catabolism-Glycolysis (Kreb Cycle)
• Anabolism-Photosynthesis

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Metabolism

• Sum of all chemical reactions
• Catabolism
• Exergonic reaction
• Most of energy in ATP last phosphate bond

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Metabolism

• Anabolism
• Consume more energy than produce
• Use ATP for energy

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Enzymes

• Biological catalysts
• Energy of activation
• Specificity
• Primary structure
• Secondary structure
• Tertiary structure
• Quaternary structure

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Components of Enzymes

• Apoenzyme-protein only
• Cofactor-nonprotein
• Trace elements
• Coenzyme-organic cofactor
• Carriers of electrons etc
• NAD

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Enzyme-substrate Complex

• Active site on enzyme
• Transformation in substrate
• Products released
• Enzyme orients substrate
• Lowers energy of activation

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Denaturation

• Structure of enzyme is disrupted
• No longer active
• Temperature
• pH
• Substrate concentration
• Enzyme becomes saturated

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Inhibitors

• Competitive inhibitors
• Noncompetitive inhibitors
• Allosteric site

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Feedback Inhibition

• End product inhibition
• Series of enzymes end product

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Energy Production

• Oxidation-reduction reactions
• Generation of ATP
• Phosphorylation
• Used for metabolism, binary fission, endospore
  formation movement

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Types of Phosphorylation

• Substrate level
• Oxidative phosphorylation
• Photophosphorylation

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Carbohydrate Metabolism

• Glucose as an example
• Two energy processes
• Cellular respiration
• Fermentation
• Glycolysis
• Respiration-Krebs cycle electron transport
  chain

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Glucose Metabolism

• C6H12O6 6O2 38 ADP 38 P
• 6CO2 6H2O 38 ATP

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Glycolysis

• Summary of glycolysis
• 2 molecules of pyruvate (3 C)
• Production of 2 NADH 2H
• Net of 2 ATP
• Substrate phosphorylation
• Takes place in cytosol of bacteria eukaryotes
• No oxygen is required
• Alternate pathways

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Cellular Respiration

• Cellular respiration
• Final electron acceptor is inorganic molecule
• Two types based on final electron acceptor

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Aerobic Respiration

• Krebs cycle
• Mitochondria of eukaryotes-matrix
• Cytosol in prokaryotes
• Intermediary step- production of acetyl CoA
• 2 CO2 2 NADH

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Aerobic Respiration

• Acetyl Co enters Krebs cycle
• 4 carbons of glucose released as CO2
• 6 NADH 2 FADH2 produced
• 2 ATP by substrate phosphorylation

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Electron Transport Chain

• Series of redox reactions
• Stepwise release of energy
• Oxygen final acceptor of electrons
• Inner membrane of mitochondria in eukaryotes
• Foldings of plasma membrane or thylakoid
  infoldings( photosynthesis)
• Occurs only in intact membranes

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Carrier Molecules

• Some carry both electrons protons (H)
• Cytochromes transfer electrons only
• Oxygen is last link of chain

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Chemiosmosis

• ATP generation
• Proton pumps
• Proton motive force
• Protein channels with ATP synthases

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ATP Production

• Protons release energy as rush through pore
• ATP produced via oxidative phosphorylation
• Damage to membrane ceases proton movement

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Anaerobic Respiration

• Final electron acceptor is an inorganic molecule
  other than oxygen
• Some use NO3 - ,SO42-
• Important in nitrogen and sulfur cycles
• ATP varies, less than 38
• Only part of Krebs cycle ETC used

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Fermentation

• Pyruvate converted to organic product
• NAD regenerated
• Doesnt require oxygen
• Does not use Krebs cycle or ETC
• Shut down
• Organic molecule is final electron acceptor
• Produces 2 ATP max

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Photosynthesis

• Conversion of light energy into chemical energy
• Anabolism (carbon fixation)-produce sugars from
  CO2
• Two stages

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Overall Reaction

• 6CO2 6H2O ATP
• C6H12O6 6O2 ADP P

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Light Reactions

• Photophosphorylation-production of ATP
• Only in photosynthetic cells
• Light energy (electromagnetic radiation) absorbed
  by chlorophylls
• Chlorophyll a
• Located in membranous thylakoids of
  chloroplasts-plants algae
• Infoldings of plasma membrane of cyanobacteria

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Light Reactions

• Electrons flow through ETC
• Electron carrier is NADP
• ATP produced by chemiosmosis

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Noncyclic Photophosphorylation

• Plants, algae, cyanobacteria
• 2 photosystems
• Produce both ATP via chemiosmosis
• Produce NADPH
• Used to reduce CO2 in dark reactions
• Able to produce sugars

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Summary

• ATP produced by chemiosmosis
• Uses energy released in ETC
• Oxygen produced from splitting of water
• H2O? 2H 2 e O
• Replace electrons lost from chlorophyll
• NADPH produced in second photosystem

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Dark Reactions

• Calvin-Benson Cycle
• Requires no light
• Uses energy from ATP (light reactions) to reduce
  CO2 to sugars
• Carbon fixation

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Summary

• Light H20 CO2

Calvin Cycle
Photosystems ETC Chlorophyll a Chemiosmosis
NADP ADP P ATP NADPH
Cellular respiration Organic cpds
sugars
O2