AGA 0316 Aula 11 Sigam o Carbono -1

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AGA 0316 Aula 11 Sigam o Carbono -1
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• RÁPIDO BALANÇO DA MATÉRIA ATÉ AQUI
• O que é a Astrobiologia?
• O que é vida? Quaestão Bio
• O Universo condições Astro
• Complexidade
• Complexidade Princípio Antrópico
• Evolução da vida na Terraem 4 milhões de anos,
  cérebro humano passa de 0,5 a 1,4 kg!
• O satélite CoRoT busca por exoplanetas (Brasil)
• Buscando a vida a) busque a água! Planetas...
• b) Busque a água a atmosfera terrestre
• c) Busque o carbono astroquímica-astrobio

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FOLLOW THE LIFE

• Follow the water
• Follow the carbon
• Follow the nitrogen
• Follow the energy
• Follow the entropy
• Follow the information

?
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Universo Orgânico!

• 0.5 da matéria bariônica visível está na
  forma molecular. (Fraser, McCoustra Willians,
  2002, AG, 43, 2.11).
• gt 150 Moléculas detectadas no espaço (50
  orgânicas CHON).

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Como as biomoléculas são encontradas?
IR-Telescopes (vibrational lines)
Radiotelescopes (rotational lines)
VLA
Itapetinga, SP
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Onde são encontradas as biomoléculas?
Key hole Nebula
Gaseous Pillars Eagle Nebula
Hale-Bopp
Murchinson
Titan
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151 interstellar and circumstellar molecules
H2
C6H6
NH3
CO
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Carbon in human body
Element Percent by mass
Oxygen 65
Carbon 18
Hydrogen 10
Nitrogen 3
Calcium 1.5
Phosphorus 1.2
Potassium 0.2
Sulfur 0.2
Chlorine 0.2
Sodium 0.1
Magnesium 0.05
Iron, Cobalt, Copper, Zinc, Iodine lt0.05 each
Selenium, Fluorine lt0.01 each
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Carbon in the Universe
Element Parts per million
Hydrogen 739,000
Helium 240,000
Oxygen 10,700
Carbon 4,600
Neon 1,340
Iron 1,090
Nitrogen 950
Silicon 650
Magnesium 580
Sulfur 440
All Others 650
2.3
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Why Carbon?

• Carbon atom can form up to 4 chemical bonds with
  many other atoms can form long and complex
  molecules
• Carbon can form compounds that readily dissolve
  in water.

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Hydrogen
Outer shell/orbits
Typically only electrons from the outer shell
(valent electrons) engage in chemical bonds
Carbon
There is an optimal number of electrons per
shell. S-shell 2 electrons P-shell 8
electrons
S-shell
P-shell
Helium
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Chemical bonds

• Covalent
• Ionic
• Hydrogen

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Carbon has 4 valent electrons can form up to 4
bonds
Methane
Ethane
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ethene
benzene
ethanol
fullerene
diamond
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Polymerization

• A polymer is a substance composed of molecules
  with large molecular mass composed of repeating
  structural units, or monomers, connected by
  covalent chemical bonds. Well known examples of
  polymers include plastics and DNA.

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2º TRABALHO DE AGA 0316 Fazer resenha sobre o
artigos Finding a second sample of life on
Earth, de Davies Lineweaver
www.astro.iag.usp.br/janot/
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Silicon life?

• Si is abundant and also can form four bonds at
  once (like C). But!
• Si bonds are much weaker complex molecules
  based on Si will be fragile
• Si does not form double bonds less variety

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Organic and Inorganic Carbon C can be in
reduced or oxidized forms. Organic
carbon Inorganic carbon (reduced)
(oxidized) CH2O CO2 carbon
dioxide H2CO3 carbonic acid Example HCO3?
bicarbonate ion Glucose -- C6H12O6 CO3
carbonate ion
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Inorganic carbon (C-O bonds only)
Organic carbon (has C-H and C-C bonds)
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Coal
Oil
JENNY HAGER/ THE IMAGE WORKS
http//www.nationalfuelgas.com
Organic carbon
http//www.upl.cs.wisc.edu/stroker/jungle.jpg
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Inorganic carbon
Seashells
http//www.cmas-md.org/Images/Sanjay/UnivTop4.jpg
Coral
http//www.summerclouds.com/Vero/Sea20Shells.jpg
http//educate.si.edu/lessons/currkits/ocean/
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Four types of organic macromoleculesin living
systems.

• Most of the molecules in the living systems are
  water (H2O) and large organic macromolecules
• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids

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Carbohydrates (sugars, starches)

• Representatives
• Glucose, Fructose
• Many hydroxyl
• groups (-OH)
• Soluble in water
• Form Polysaccharides
• Good energy source
• Structural support for
• organisms (cellulose
• - the main constituent of wood)

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Glucose
Fructose
Table sugar
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Glucose polymerization
H2O
Linked by dehydration reaction
Polysaccharides
In starch molecule (potato) there can be 100s
thousands of glucose units
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Lipids (fats and oils)

• Representatives fatty acids and cholesterol
• Poorly soluble
• Good (concentrated)
• energy source
• Flexible
• (cell membrane material)

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Proteins

• Proteios primary
• Long trains of amino acids
• Different proteins have different sequence of
  amino acids
• 20 amino acids used in any organism
• Some provide structure (fingernails, hair)
• Some serve as catalysts
• Enzymes proteins with catalitic properties

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L-Alanine
Glycine
Linked by dehydration reaction
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Catalysts in Chemistry

• Suppose chemical reaction
• A B ? AB is a slow reaction
• The same reaction can be accelerated with
  catalyst (D)
• A D ? AD fast step
• B AD ? AB D fast step
• The net result is still
• A B ? AB but it is much faster

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Proteins (continued)

• Even though there are 70 amino acids any known
  life uses only 20
• Amino acids derived abiotically are a mix of both
  left-handed and right-handed ones. Biological
  amino acids are only left-handed.
• Chirality
• Was there a common ancestor for all life?

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Biology uses only left-handed Alanine
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Qual a Origem do Carbono?
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Credit Y.Pendleton
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Nebulosas Planetárias

• O Sol vai morrer assim
• Estrelas com massas menores que 8 vezes a massa
  do Sol
• Núcleo ??anã branca
• Camadas exteriores ???nebulosa planetária
• C, N
• Tempos até varios Ganos
• Promovem as condições pré-bióticas.

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Large carbonaceous molecules in space
Diamond ltlt
Graphite ?
Fullerenes 0.5
PAHs 15
C-chains 0.1
gt 50 ??
C-onions
Soot
Nanotubes
Ehrenfreund Charnley 2000
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Meteorites

• A meteorite is a natural object originating in
  outer space that survives an impact with the
  Earth's surface without being destroyed.
• Chondrites 86
• (5 Carbonaceous Chondrites)
• Achondrites 8
• Iron meteorites 5

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Meteorites represent the only extraterrestrial
material which can be studied on Earth !
Insoluble C-fraction 60-80 aromatic
carbon highly substituted small aromatic moieties
branched by aliphatic chains
Murchison (1969, Australia)
Volatile fraction
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Abundances of soluble organic compounds in the
Murchison meteorite (Botta Bada 2002, Sephton
2002, 2004)

Compound Class Concentration(ppm) Amino
Acids CM 17-60 CI 5 Aliphatic
hydrocarbons gt35 Aromatic hydrocarbons
3.3 Fullerenes gt 1 Carboxylic acids gt
300 Hydroxycarboxylic acids 15 Dicarboxylic
acids Hydroxydicarboxylic acids 14 Purines
Pyrimidines 1.3 Basic N-heterocycles
7 Amines 8 Amides linear gt 70 cyclic gt
2 Alcohols 11 Aldehydes Ketones 27 Sulphonic
acids 68 Phosphonic acids 2

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2º TRABALHO DE AGA 0316 Fazer resenha sobre o
artigo Finding a second sample of life on
Earth, de Davies Lineweaver
www.astro.iag.usp.br/janot/
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QUESTÕES SOBRE A AULA 11 1) Onde há Carbono no
Universo? 2) Porque o C e um elemento-chave para
a vida? 3) Dê exemplos de compostos de C que
encontramos habitualmente. 4) Porque a
quiralidade é um elemento-chave para a descoberta
de vida extraterrestre?