Lecture 16 - Origins of Life Flashcards
What are the 7 ways that life is defined?
- metabolism
- reproduction
- cellular organization
- homeostasis
- growth
- adaption
- response to stimuli
Evolution is a theory about the origin of life (T/F)
False
What did Darwin believe about all organisms?
They trace back to a single ancestor
Was life on earth possible at the beginning?
no
What happened 4.6 billion years ago?
formation of earth
What happened 4.2 BYA? What did that encompass?
- stable hydrosphere
1. bombardment ends
2. earth cools
3. oceans form
What is prebiotic chemistry? What years?
- 4.2-4.0 BYA
1. abiotic synthesis of small organic compounds
2. joining of small molecules into macromolecules
3. packaging of molecules into protocells
What are some examples of small organic compounds?
CH4
What is an organic compound?
C with H bonds
What is the Oparin-Haldane hypothesis?
- atmosphere was reducing (electron adding)
- catalyze reactions to form more complicated organic molecules from simpler molecules.
- energy for synthesis may have come from lightning + UV radiation
Who was Stanley Miller?
- Chicago student
- made contraption (added lightning to simple compounds)
- tested Oparin-Haldane hypothesis
- found amino acids after 7 days
What are 3 ways that organic compounds could have been formed?
- under volcanic or hydrothermal conditions
- hydrothermal conditions
- brought to Earth on meteorites
What year was the Miller Urey experiment?
1953
What are macromelcules
EX: amino acids into proteins
What serves as catalysis for macromolecule formation?
clay surfaces
What are protocells?
aggregates of abiotically produced molecules surrounded by a membrane/membrane-like structure
What do protocells exhibit?
- simple reproduction and metabolism
- maintain internal chemical environment
How are protocells formed?
could be spontaneous
When does vesicle self-assembly accelerate?
in the presence of a substrate
What happened 4.0 BYA
pre-RNA world
What happened 3.8 BYA
RNA world
What are 4 functions of RNA?
- catalyzes reactions (ribozymes)
- central to protein synthesis
- self-replicating
- stores information
What happened 3.7 BYA
first DNA/protein life
Why was the first DNA/protein life stage so important?
oldest possible life forms
When was earth formed?
4.6 billion years ago
What are stromalites?
- layers of rocks
- composed of layers of cynaobacteria separated by sediment
What is LUCA?
last universal common ancestor (3.6 billion years ago - present)
Was life possible 4.6 BYA? Why or why not?
- no
1. extreme heat
2. water vaporization
3. bombardment
What were 3 characteristics of the last universal common ancestor?
- thermophilic
- anaerobic
- autotrophic
What may have proceeded RNA as the genetic code?
peptide nucleic acid
