Prokaryotic vs.
Eukaryotic Cells
• All cells fall into one of the two major classifications of prokaryotes and eukaryotes.
Prokaryotes were here first and for billions of years were the only form of life.
• Prokaryotes are unicellular organisms, found in all environments. Prokaryotes are the largest group of organisms, mostly due to the vast array of bacteria which comprise the bulk of the prokaryote classification.

Characteristics:
• No nuclear membrane (genetic material dispersed throughout cytoplasm)
• No membrane-bound organelles
• Simple internal structure
• Most primitive type of cell (appeared about four billion years ago)

Examples:
• Staphylococcus
• Escherichia coli (E. coli)
• Streptococcus
– Note that all of the above are different strains of bacteria.
• Eukaryotes are generally more advanced than prokaryotes. There are many unicellular organisms which are eukaryotic, but all cells in multicellular organisms are eukaryotic.

Prokaryotic vs.
Eukaryotic Cells

Characteristics:
• Nuclear membrane surrounding genetic material
• Numerous membrane-bound organelles
• Complex internal structure
• Appeared approximately one billion years ago

Examples:
• Paramecium
• Dinoflagellates
• sapiens (Humans)

Prokaryotic vs.
Eukaryotic Cells
• It is hypothesized that a primitive bacterium once surrounded its food after releasing its digestive enzymes.
The membrane folded inward and pinched off, creating the first digestive membrane-bound organelle.

And now it's storytime!
• Once upon a time (about one billion years ago), the first eukaryotic cell came to be. There was a group of primitive bacteria going about their business when along came a big hungry phagocyte, who ate one of the bacterium.
– Mr. Phagocyte: Yum.Bacterium: Excuse me.Mr. Phagocyte:
What?
Bacterium: You know, why don't we join forces and I can help you and you can help me and we can become a 'eukaryotic' cell?
Whaddaya say?
Mr. Phagocyte: OK. The little engulfed bacterium evolved and became the mitochondria in present-day cells.
Obviously, they all lived happily ever after.

Prokaryotic vs.
Eukaryotic Cells
• Review

Assigned activities
• Read Pages 23-24 in McGraw Hill Ryerson
• Through an online search look up the definition of the term symbiosis. Answer the following Question:
– How is this term applicable to the development of the Eukaryotic Cell?

• Review
Test YourSelf