1. NOTES: 7.1 - Introduction to the Cell

2. Cell Theory All living things are composed of 1 or more cells.
Cells are the basic unit of structure & function in living things.
New cells are produced from
existing cells.

3. MICROSCOPES Light Microscope Electron Microscope (1940’s)
Scanning Electron Microscope
Transmission Electron Microscope

4. Light Microscope
works by passing visible light through a thin section of specimen and then through glass lenses
magnification about 1000x x

6. Electron Microscope (1940’s)
uses electron beams which have shorter wavelengths of light (so you can see smaller objects…more detail)
magnification up to 500,000x

7. Electron Microscope Scanning Electron Microscope
electron beam scans the surface of a specimen
useful for studying the surface of specimen in 3-D
Transmission Electron Microscope
electrons transmitted through specimen
used to study internal cell structure

9. Disadvantages to EM…
can only view dead cells (preparation steps kill living cells)
very expensive
zooxanthellae cells cultured from coral Aiptasia pulchella in a Scanning Electron Microscope

10. Cell Types
& Classification!

11. ALL CELLS: have a cell membrane have cytoplasm have ribosomes
can reproduce & contain genetic material

12. CELLS CAN BE CLASSIFIED AS:
1. PROKARYOTES
2. EUKARYOTES
See… no nucleus!!!
See… a nucleus!!!

13. PROKARYOTES EUKARYOTES
oldest cells (3.5 billion years)
“newer” cells (1.5 billion years)

14. PROKARYOTES EUKARYOTES
oldest cells (3.5 billion years)
single celled
“newer” cells (1.5 billion years)
single or multicellular

15. PROKARYOTES EUKARYOTES
oldest cells (3.5 billion years)
single celled
lack nucleus & membrane-bound organelles
“newer” cells (1.5 billion years)
single or multicellular
have a “true” nucleus & membrane-bound organelles

16. PROKARYOTES EUKARYOTES
oldest cells (3.5 billion years)
single celled
lack nucleus & membrane-bound organelles
genetic material in a single, circular molecule
“newer” cells (1.5 billion years)
single or multicellular
have a “true” nucleus & membrane-bound organelles
genetic material organized and in nucleus

17. PROKARYOTES EUKARYOTES
oldest cells (3.5 billion years)
single celled
lack nucleus & membrane-bound organelles
genetic material in a single, circular molecule
small (1-2 µm)
“newer” cells (1.5 billion years)
single or multicellular
have a “true” nucleus & membrane-bound organelles
genetic material organized and in nucleus
larger ( µm)

18. PROKARYOTES EUKARYOTES
oldest cells (3.5 billion years)
single celled
lack nucleus & membrane-bound organelles
genetic material in a single, circular molecule
small (1-2 µm)
Domains Bacteria & Archaea (bacteria)
“newer” cells (1.5 billion years)
single or multicellular
have a “true” nucleus & membrane-bound organelles
genetic material organized and in nucleus
larger ( µm)
Kingdoms Protista, Fungi, Plantae, Animalia

20. NUCLEUS • membrane-bound organelle in eukaryotic cells;
• contains the cell’s DNA
enclosed by a nuclear envelope
contains all of the information for cell to function