Lesson 2: Origin of cells Flashcards
What are protocells?
first cells
What was the atmosphere of pre-biotic earth like?
Reducing gasses: ammonia, methane, hydrogen and carbon dioxide
No ozone layer
Many electrical storms
Very hot (100C+)
UV and Solar radiation
What were the 4 requirements in the evolution of the first cells?
Catalysis
Self-Assembly
Self-Replication
Compartmentalisation
What was the conclusion drawn from the miller-urey experiment?
Biological molecules can be formed from simple inorganic molecules
What are some limitations to the miller-urey experiment?
There is still a debate of what earth’s early atmosphere was really like.
The experiment did not produce all of the organic molecules required for life such as nucleotides.
The simulation could not account for all conditions on the prebiotic Earth.
Added more methane there actually was.
What were the strengths of the experiment?
Modelled prebiotic Earth and its atmosphere.
Demonstrated that molecules such as amino acids can be generated spontaneously under certain conditions.
The design of the experiment allow it to be replicated by other scientists.
Why is a membrane important?
Allows the internal environment/chemistry of the cell to differ from the external environment.
What are some evidence for LUCA evolving from hydrothermal vents?
oldest fossils found there
reducing environment to form complex carbon compounds
modern organisms near thermal vents have similar genetic sequences suggesting a common ancestor.
What was the first genetic material?
RNA
Why was RNA the first genetic material?
RNA can both self-replicate and has catalytic activities.
why has DNA become the main genetic material?
more stable (double helix instead of singular).
Why has protein become the main catalytic molecule?
capable of more variation
What does LUCA stand for?
last universal common ancestor
What is the definition of LUCA?
The most recent common ancestor for all organisms on Earth.
How long ago was LUCA?
Appeared approximately 4 billion years ago
