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The Origin of Cells, Endosymbiosis - Coggle Diagram
The Origin of Cells
Origin of First Cells
A rule of cell theory:
Cells come from pre-existing cells
But the first ever cell must have arisen from non-living materials
Hydrocarbons molecules
At start the only living organisms are
simple prokaryotic cell
Unicellular
No membrane-bound organelles
Some cells have the ability to
absorb
other cells or bacteria
Absorbing bacterial cells with unique functions
i.e. photosynthesis, respiration, etc.
Eventually multiple cells living and working together in one cell
One organism living inside another
Pasteur's Experiments
Louis Pasteur
French Chemist and microbiologist
Discoveries on vaccination, microbial fermentation
Constructed the process of
Pasteurization
Swan-Neck Flask Experiment
Disproving the doctrine of
Spontaneous Generation
Spontaneous Generation
Living things develop from nonliving matter
Develop out of nothing
Life comes from other living things
A apparatus made to let air flow into the flask but block external particles by the curve neck design
Since the neck blocks off external materials getting in, the broth is previously sterilized and will not be contaminated
Later Pasteur breaks the neck open, leaving the flask open. Within a few days there's microbial growth
Thus disproving the idea of spontaneous generation
Spallanzani's Experiment
Bacteria can be destroyed by boiling
Microbes will not re-appear as long as the material was sealed away from air
People criticized Spallanzani about his experiment since no air is going in, bacteria can't grow and organisms cannot live without air
Endosymbiotic Theory
An explanation of how complex cells
evolved
How prokaryotic cells evolved into eukaryotic cells
Evidences of theory
Some organelles in cells divide or reproduce in a similar way as bacteria
Organelles have their own separate DNA
Some are similar to bacterial DNA
Sizes of organelles are similar to bacteria
Endosymbiosis
More and more bacteria get absorbed and became an eukaryotic cell with complex structure
Slowly the bacteria (prokaryotic cells) absorbed turn into the organelles in cells we know today
i.e. mitochondria, chloroplasts
