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Chapter 3

Biology 1202B Chapter Notes - Chapter 3: Polycyclic Aromatic Hydrocarbon, Louis Pasteur, Allan Hills 84001


Department
Biology
Course Code
BIOL 1202B
Professor
Richard Gardiner
Chapter
3

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Biology Text Book Notes
Lecture 1: Chapter 3 Origin of Life
Panspermia:
Asteroids (coming from mars) brining organic matter to earth proving that
there could have been life on MARS
ALH84001: found to be 4.5 billion years old
o Same age as our solar system (earth was formed 4.6 billion years
ago)(universe was formed 15 billion years)
Strong evidence that there was life on mars
o ALH84001 had been fractured and subsequently split by liquid H2O
o Fossilized prokaryotes found on ALH84001
o Found microscopic minerals “globules’; strong resemblance to
mineral alteration caused by primitive prokaryotes on earth
o Meteorite contains an abundance of polycyclic aromatic hydrocarbons
(PAH)
Formed when microorganisms die
What is life
Atoms found in living are no different then atoms in non living things
(abiotic)
Follow same fundamental laws of chem. And physics
7 Characteristics of Life:
1. Display order
2. Harness and utilize energy
3. Reproduce respond to stimuli
4. Exhibit homeostasis
5. Growth and development
6. Evolve
**Virus is not considered alive
lack the cellular machinery to synthesize their own proteins
Spontaneous Generation:
Living matter cannot generate spontaneously from non-living matter
o Louis Pasteur
Different in earlier earth; First cell arose where there had been no life
Louis Pasteur proved there is no spontaneous generation but not how the
first cell came alive
Cell theory
1. All organisms are composed of one or more cells
2. The cell is the smallest unit that has the properties of life
3. Cells arose only from the forth and division of preexisting cells
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Early Atmosphere
Very different then today
o Today is oxidizing atmosphere
o Today is colder then the early
The early atmosphere had
o No ozone (03) due to lack of O
o Abundance of H2O vapor
o Large quantizes of H2S, CO2, NH3, CH4
o Reducing atmosphere
No free O2
o Free hydrogen and Hydrides (CH4, NH3, H2O)
o Energy-electric discharge in storms or solar energy
No ozone layer
Oparin-Haldane Hypothesis
- Maximum number of H and electrons fully recued
o Rich electrons can be donated to make reaction occur which can lead
to the build up of complex organic molecules
Miller-Urey Experiment
- Oparin and Haldane hypothesized the ultra violet light and abundant of
lightening provide energy that combined with reducing condition lead to the
accumulation of building blocks required for life.
- Later Miller and Urey tested the hypothesis
o Recuing components into apparatus and exposed to continous sparks
H2O vapour was added
o After a week organic compounds were found
Urea
Amino acids
Lactic
Formic
Acetic acid
Others now also found
Hydrogen cyanide HCN
Formaldehyde CH2O
Polymers
- Nucleic acid are polymers or nucleotide
- Proteins are polymer of simple sugar
- Polymers wouldn’t have survived in the aqueous environment or primordial
earth as they would have hydrolyzed
o Hydrolyzed: break down by adding H2O
o Condensation: forming polymers by removing water
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