dp bio topic 1-5 the origin of cells
TRANSCRIPT
Cells can only be formed by division of pre-existing cells
Evidence:• No natural mechanism to
produce cells from simpler subunits• No example of cell number
increasing without cell division• Viruses are produced from
simpler subunits but not made of cells and can only reproduce inside host cells
The first cells must have arisen from non-living material
Where did the first cells come from?Hypothesis: • A series of stages over long
periods of time• Evolved over a period of
hundreds of millions of years
The origin of eukaryotic cells can be explained by the endosymbiotic theory
• Explanation for mitochondria, chloroplasts, and mDNA & ctDNA• Mitochondria & chloroplasts
were once free-living protists• Taken in by larger protists• Mutualistic relationship
Smaller cell supplied w/food or resources
Larger cell supplied w/ energy
Sources
Content Allott, Andrew, and David Mindorff. Biology: Course Companion. 2014 ed. Oxford: Oxford UP, 2014. Print. Oxford IB Diploma Programme.
Walpole, Brenda. Biology for the IB Diploma. 2nd ed. Cambridge: Cambridge UP, 2014. Print.
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