Cells and Cell Structures

“Cell”• Name means “small room”• Basic structural, functional

and biological unit of all KNOWN living organisms

• Smallest unit of life that can replicate independently

Microscopes were used as early as the 1600s to look at things.

• 1665 Hooke used a microscope to look at the bark of a Cork-bark oak

• Saw this and named them ‘cells’

• Snowflake

• 1838: Schleiden concluded all plants are made of cells

• 1839: Schwann stated all animals were made of cells

• 1855: Virchow concluded new cells can only be produced from existing cells

Spurred more interest… better technology

Cell Theory• All living things are made of

cells• Cells are the basic structural

and functional unit of living things

• New cells are produced from existing cells

Cell Theory• What IS a theory?• Why is it “Cell Theory” and not “Cell Law”?• Do we know about “ALL living things”?

• Two (broad) categories of cells

• NO membrane-bound organelles = Prokaryotes

• HAS membrane-bound organelles = Eukaryote

Prokaryotes and Eukaryotes

Scanning electron micrograph of E. coli in human intestine

www.listoid.com

Scanning electron micrograph of human brain neuron

www.scienceclarified.com

• Smaller and ‘simpler’

• Bacteria are prokaryotes

• MOST living things are prokaryotes

Prokaryotes

Prokaryotes

• Smaller and ‘simpler’

• Bacteria are prokaryotes

• MOST living things are prokaryotes

• MOST of ‘you’ is prokaryotic

• YOU are outnumbered 10:1 in/on YOU!!!!

Prokaryotes

American Society for Microbiology, June 5, 2008

Scale between human cells and bacterial cell

• Larger, more ‘complex’

• Eukaryotes have a nucleus

• MOST have other organelles

• Protists to animal/plant cells

Eukaryotes

Daphnia are NOT protists. They’re related to lobsters- Crustaceans

• Review your notes!!!!!!!!!!!!!!!

Homework