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abiogenesis or spontaneous generation
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jean von helmont
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origin of life

QuestionAnswer
abiogenesis or spontaneous generation life comes from nonliving things. ex: people believed that the Nile mud spawned snakes and frogs, and food waste was the direct cause of maggots.
jean von helmont tried to prove abiogenesis. he put a dirty shirt into a barn; 21 days later, he found mice there. he thought this proved the theory.
leeuwenhoek he discovered microorganisms.
needham boiled chicken for LESS than five minutes and then placed in a sealed flask. He found that microorganisms grew. (proving abiogenesis)
spallanzini boiled chicken for more than 5 minutes and then placed in a sealed flask. He found that NO microorganisms grew. (disproving abiogenesis)
francesco redi meat into a glass jar and found that flies were inside; then covered with an airtight top; found that no flies were there. people claimed he had killed the life (gives rise to flies) of airflow; so then, he covered jar with cheesecloth; still no flies.
louis pasteur took chicken broth and boiled it for more than 5 minutes. Then he made an S-shaped bottle to prove that the bacteria is caused by undercooked chicken, not out of the 'air' or by the chicken. microorganisms linked to disease.
biogenesis life comes from life
origin of life/organic soup theory discovered in the 1920s by Oparin and Haldane.
urey and miller 1953- duplicated the primitive atmosphere and after one week produced two amino acids.
Sidney Walter Fox took the Urey/Miller experiment further and produced proteins.
microspheres one type of molecule- like a ring of phospholipids
coacervates several types of molecules- ex, phospholipids with proteins throughout (NO DNA-meaning not a cell)
primitive earth, 4.5 billion years ago all hot magma; the atmosphere is cold, so the earth is slowly cooling.
primitive atmosphere had H2 (hydrogen gas), H20 (water vapor), NH3 (ammonia), CH4 (methane). There is no free oxygen. There is also no Ozone layer (O3) which means the sun is shining too brightly- radiation!
what types of energy convert primitive gases into ions... UV, heat, radioactive materials, and lightning
H20 turns from vapor into water as it rains for millions of years, meaning.. water pulls ions out of the atmosphere and into the newly collected water basins (since water has a polar covalent bond)
as the rain erodes crust, what enters the water basins? phosphorus and salts enter the water basins, meaning that important materials enter the water and can bond with ions to form the building blocks of life.
ions recombined forming WHAT simple organic molecules? monosaccharides, glycerol, fatty acids, amino acids, and nucleotides.
these simple organic molecules form more complex organic molecules such as... polysaccharides, lipids, proteins, DNA, and RNA.
phospholipids- important why? since the glycerol part of phospholipids are hydrophilic while the fatty acids are hydrophobic, they formed spheres called microspheres; eventually, proteins entered these spheres. this led to the formation of cell membranes.
DNA in the core of a microsphere/coacervate makes a cell
the first cell heterotrophic, anaerobic, and prokaryotic; anaerobic respiration led to CO2 being released into the air.
CO2 in the atmosphere means that.. chemosynthesis can occur
evolution leads to... photosynthesis being able to occur (more sun protection with Ozone layer); this means that free oxygen can also enter the atmosphere.
oxygen in atmosphere aerobic respiration can occur--> leads to Eukaryotic cells.
ozone finally forms fully life can leave the seas.
endosymbiosis the relationship (mutualism) between organisms like the mitochondria, chlorophyll and the ancient prokaryotic cells which eventually led to simple cells becoming complex and life finally evolving into actual organisms.
Created by: user-1735208
 

 



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