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Evolution of Oxygen Levels in Earth’s Atmosphere. Carboniferous. Jurassic. Volume % Oxygen. Cenozoic era. Permian. Cambrian. Precambrian . Ordovician. Devonian. Silurian. Triassic. Millions of Years before Present. Evolution of Oxygen Levels in Earth’s Atmosphere. Carboniferous.

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Presentation Transcript
slide1

Evolution of Oxygen Levels in Earth’s Atmosphere

Carboniferous

Jurassic

Volume % Oxygen

Cenozoic era

Permian

Cambrian

Precambrian

Ordovician

Devonian

Silurian

Triassic

Millions of Years before Present

slide2

Evolution of Oxygen Levels in Earth’s Atmosphere

Carboniferous

Jurassic

Volume % Oxygen

Cenozoic era

Permian

Cambrian

Precambrian

Ordovician

Devonian

Silurian

Triassic

Millions of Years before Present

why is oxygen important
Why is oxygen important?

Glycolysis

Glucose + 2 NAD+ + 2 Pi + 2 ADP → 2 pyruvate+ 2 NADH + 2 ATP + 2 H+ + 2 H2O + heat

Oxidativephosphorylation

mitochondria and oxygen
Mitochondria and oxygen

Electron transport chain

Q cytochrome c reductase (complex III)

produces a radical intermediate and

can be leaky releasing electrons in the cell

slide5
The leaky system produces Reactive Oxygen Species that include:superoxide, hydrogen peroxidehydroxyl radicals

Evolution has coopted some as important signaling molecules:

  • Hydrogen peroxide
  • Nitric oxide
  • Hydrogen sulfide
  • Carbon monoxide
valency flexibility
Valency flexibility
  • Sulfur
  • Phosphorus
  • Selenium
  • Nitrogen
slide8

Atomic Number:16 Atomic Radius: 104 pm

Atomic Weight:32.06 Electron Configuration: [Ne]3s23p4

Oxidation States: 6, 4, 2, -2

# cysteines

in genome

Biological complexity

200,000 cysteines in

human proteome

slide9

Nitrogen

Atomic Number:17Covalent Radius: 71 pm

Atomic Weight:14.01 Electron Configuration:[He] 2s22p3 2, 5Oxidation States: 5, 4, 3, 2, 1, −1, −2, −3

Nitric Oxide

slide10

Atomic Number:34 Atomic Radius: 120 pm

Atomic Weight:78.97 Electron Configuration:[Ar] 3d10 4s24p4 2, 8, 18, 6

Oxidation States: 6, 4, 2, 1, -2

slide11

Atomic Number:15 Atomic Radius: 107 pm

Atomic Weight:30.97 Electron Configuration:[Ne] 3s23p3 2, 8, 5

Oxidation States: 5, 4, 3, 2, 1, −1, −2, −3

0.7 kg of phosphorus

Human genome has ~500 protein kinase genes (2% of genome].

~30% of all proteins may be modified by kinases, regulating many signal transduction pathways.

cycles provide regulatory control
Cycles provide regulatory control

Post-translational alterations in signaling proteins can add a layer of regulatory control. Two examples of which are:

  • Kinase and phosphatases
  • Glutathione S-transferases and glutaredoxins
  • These pathways can control cell growth/division and as such make logical targets for pharmaceutical interventions
some examples of drug targets
Some examples of drug targets
  • Sulfur - protein folding machinery
  • Phosphorus - protein kinases
  • Nitrogen – nitric oxide vasodilators
  • Selenium – chemoprevention in cancer