How is life synthesized from non-living ingredients?

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How is life synthesized from non-living
ingredients?

• Examining the processes of photosynthesis and
  cellular respiration

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Do all autotrophs photosynthesize?

• Autotrophs are producers that can make their own
  food from inorganic substances, using sunlight or
  other energy to fuel the reaction.

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Do all autotrophs photosynthesize?

• There are two main types of autotrophs
• Photoautotrophs- require photons from the sun to
  carry out their oxidative reactions,
• cyanobacteria and plants are most famous
• Chemoautotrophs- do not require the sun to carry
  out their oxidative reactions,
• Bacteria that live in extreme conditions (sulfur
  vents etc.)

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Chemiosynthesis came first

• Bacteria (prokaryotes no nucleus) were first
  form of life on Earth.
• Early Earth environment very extreme conditions.
• Probably used inorganic molecules such as sulfur
  and iron compounds to fuel energy production
  through internal chemical reactions (metabolism).
• In the struggle for survival (the winners
  reproduce most) efficient use of energy is vital.

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Photosynthesis wins out

• Many complex organic molecules form from simpler
  molecules.
• Cells that produce a molecule like chlorophyll
  that can harvest the suns energy provide a huge
  survival advantage.
• Natural selection organisms that have favorable
  traits in a particular environment are more
  likely to produce more offspring and pass on the
  favorable trait.

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Photosynthesis changes the Earth

• Photosynthetic organisms out compete
  chemosynthetic organisms at the Earths surface.
• Waste oxygen produced by photosynthetic organisms
  (cyanobacteria) makes the Earths atmosphere
  poisonous to the chemosynthetic organisms.

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Endosymbiotic Theory

• This theory proposes that eukaryotic cells arose
  from symbiosis among several prokaryotic cells.
• What evidence is there to support this idea?
• Mitochondria and chloroplasts contain DNA that is
  similar to bacterial DNA.
• They also have ribosomes similar to bacterial
  ribosomes
• Like bacteria, mitochondria and chloroplasts
  reproduce through binary fission, but eukaryotic
  cells divide by mitosis.

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One bacteria engulfs another
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Endosymbiotic Theory
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Consider how life and the environment are
interconnected

• Changes in the contents of the atmosphere
• Changes in habitable places as the ability to
  photosynthesize became common-place

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Adaptations

• As conditions on the planet changed, populations
  needed to adapt in order to survive.
• Adaptations are inherited character-istics that
  increase an organisms chance of survival.

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Examples of adaptations
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Photosynthesis

• is a process
• involves CO2, H2O and sunlight as reactants in a
  chemical reaction
• produces C6H12O6 and O2 as products.
• Where and how does this take place?

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Inside the leaf of a plant

• Use your textbook, pg 596 to label these parts
• xylem
• Phloem
• Epidermis
• Palisade mesophyll
• Cuticle
• Stoma
• Spongy mesophyll
• Guard cells

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Plant Cell Structure
Does this look familiar? Working with your table
partners, identify each cell part and summarize
the function of each.
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Photosynthesis

• inside the chloroplast of a eukaryotic plant
  cell
• the structure of the chloroplast is adapted in
  ways that facilitate the photosynthetic process,
• pigments in the chloroplast absorb and reflect
  different wavelengths of sunlight to make
  photosynthesis possible.

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Inside the chloroplast

• ___ CO2 ___ H2O Sunlight
  ___ C6H12O6 ___ O2
• (reactants) (products)
• Can you balance the chemical equation?
• Because sunlight is such an essential ingredient
  in this equation, cells have adapted structures
  that help to absorb the sunlight and use it to
  trigger the chemical reaction above
• Use the concept map to help you map the steps of
  this reaction-

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Examples of adaptations

• Is the ability to photosynthesize an example of
  an adaptation?
• If so, how?
• If not, why not?
• How does photosynthesis increase an autotrophs
  chance of survival?

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How did producers evolve?

• Amino acids -gt polypeptides (precursors of
  proteins) -gt coacervate molecules (clusters of
  macromolecules surrounded by a shell of water
  molecules) -gt nucleic acids (self-replicating and
  subject to natural selection) -gt lots more time
• Prokaryotic autotrophs
• Lack an inner membrane around nucleus, small ex
  bacteria
• Eukaryotic autotrophs
• Have membrane organelles like chloroplasts
  ex plants

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Last one
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How is this adapted?
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How is this adapted?
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How are these adapted?