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Biogenesis and Origin of Life

Biogenesis and Origin of Life. Chapter 14 -1 Pg. 279-281 and 284-290. Where did these mice come from?. Origin of Life. Biogenesis : life comes from other living organisms Spontaneous generation : early theory that life comes from non-living organisms.

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Biogenesis and Origin of Life

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  1. Biogenesis and Origin of Life Chapter 14 -1 Pg. 279-281 and 284-290

  2. Where did these mice come from?

  3. Origin of Life • Biogenesis: life comes from other living organisms • Spontaneous generation: early theory that life comes from non-living organisms

  4. Evidence Against Spontaneous Generation • Redi’s experiment • Indicated that maggots didn’t come from rotting meat because flies couldn’t land

  5. Evidence Against Vital Force • Early Idea • Vital force: Something in the air that gave rise to life • Spallanzani’s experiment: Disproved that organisms came from “vital force” by preventing air contact

  6. Evidence Against Vital Force • Pasteur’s experiment: Showed that micro-organisms in the air contaminated the flasks disproving “vital force”

  7. First Life Forms/First organic compounds • Spontaneous Origin: the process of life developing from non-living chemical interactions • Ex. “Primordial Soup”

  8. Evidence Supporting Spontaneous Origin • Oparin: (1920) Hypothesized that primitive Earth’s atmosphere was • NH3, H2, H2O, and CH4 • [No Oxygen] • Miller-Urey: (1953) Produced organic compounds based on the hypothesized composition

  9. Primordial Soup: Water • Water has a positive (+) and a negative (-) pole • This makes it polar • Polar substances like water will dissolveother polar substance • Like dissolves like • Pulls apart ionic molecules like NaCl

  10. Water bonding • Hydrogen bonds: bonds BETWEEN water molecules (the hydrogen from one water molecule bonds with the oxygen from another water molecule)

  11. Molecules to cell-like structures • Non-polar molecules start to group up to avoid water • Leading to cell-like structures beginning to form • Coacervates: Droplets that are made of different macromolecules • Microspheres: small spheres that are made of many protein molecules organized into a membrane

  12. First Life FormsRole of RNA • Amino acids linked to make a chain that could make shapes like ribozymes (early ribosome) which could replicate itself

  13. First Life Forms- The First Cells • Prokaryotes before eukaryotes • 3 major trends all interrelated: • Anaerobic  Aerobic • Heterotrophic  Autotrophic • Chemosynthetic  Photosynthetic

  14. The First Eukaryotes • Endosymbiosis Theory • Mitochondria (aerobic prokaryote) and chloroplasts (photosynthetic prokaryote) are thought to be prokaryotic cells that were engulfed by a bigger prokaryote • Created mutually beneficial relationship • Safer environment in exchange for energy source • Supporting evidence: • They have their own DNA • DNA is circular like other prokaryotes • Replicate on their own

  15. Sequence of First Cells Anaerobic Heterotrophic Prokaryotes Chemosynthetic Prokaryotes Photosynthetic Prokaryotes Endosymbiosis Occurs Here! Aerobic Eukaryotes Photosynthetic Eukaryotes

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