1. Discovering Cells…

2. Anton van Leenwenhoek Dutch scientist
The first person to look at water using a single-lens microscope in the mid-1600’s.
He was surprised to see the water was full of living things:
“animalcules”

3. van Leenwenhoek Microscope

4. Robert Hooke English scientist
Studied cork using a compound light microscope.

5. Hooke Microscope

6. CELLS
He observed tiny geometric shapes and named them “cells” because they reminded him of the small rooms monks lived in at the monastery.

7. Robert Hooke published 'Micrographia' in 1665
Robert Hooke published 'Micrographia' in It is his most famous work, and is notable for the stunning illustrations, drawn by Hooke himself.

8. The picture of the flea shown is one of his most famous images; the original is 18 inches across.

9. Additional Hooke drawings

10. Matthias Schleiden German scientist
Observed different plants and concluded that all plants are composed of cells in the 1830’s.

11. Theodore Schwann German scientist
Made observations that all animals are composed of cells.

12. Robert Brown Scottish scientist
Observed that all cells contained a prominent structure that appeared to be a “blob” in the center of the cell…the nucleus.

13. Rudolf Virchow
Concluded that the nucleus was the structure responsible for cell division.

14. Together, these men developed The Cell Theory:

15. The Cell Theory 1. All organisms are composed of one or more cells.
2. The cell is the basic unit of organization of organisms.
3. All cells come from preexisting cells.

17. Compound Light Microscopes
Uses 2 or more glass lenses to magnify objects.
Can magnify up to 1500 times.

18. Compound Light Microscopes

19. Scanning Electron Microscope
Sweeps a beam of electrons over the surface of a specimen causing electrons to be emitted from the specimen.
Produce a realistic, 3D image…but only on the surface.
Can magnify about 60,000 times.

20. Scanning Electron Microscope

21. Transmission Electron Microscope
Aims a beam of electrons through a specimen
Two-dimensional images are used to study details of cells
Can magnify hundreds of thousands of times.

22. Transmission Electron Microscope

23. Blood Cells
Compound Microscope
TEM
SEM

24. LOOKING AT CELLS FORM DEFINES FUNCTION VARIOUS SHAPES
A cell’s shape reflects its function.
VARIOUS SHAPES
Branched
Flat
Round
Rectangular
Irregular
Change shapes

25. CELL SIZE
Cell size is limited by a cell’s surface area-to-volume ratio
Cells get larger…need more nutrients…release more waste.
The substances have to move farther to reach their destination

26. CELL FEATURES (Venn Diagram?)
ALL cells share common structural features:
Cell membrane
Cytoplasm
Ribosomes
DNA

27. Two Types of Cells Prokaryotes Pro = before Karyon = nucleus
Lacks a nucleus
Pro = before
Karyon = nucleus
Eukaryotes
Has a nucleus
Eu = true
Karyon = nucleus

28. Two Types of Cells Prokaryotes Small, simple, single-celled organisms
BACTERIA
Eukaryotes
Complex, multi-celled organisms
PLANTS & ANIMALS

29. Internal compartments (membrane-bound organelles)
Two Types of Cells
Prokaryotes
Do NOT have:
Eukaryotes
DO have:
Internal compartments (membrane-bound organelles)

30. Eukaryotic cells can carry out more specialized functions because of their complex organization (organelles).

31. Cell Division Cell Membrane Ribosomes
Nucleus
No Nucleus
Complex, multi-celled organisms
Small, simple, single-celled organisms
DNA
Cell Division
Cell Division—
Binary Fission
Cell Division—
Mitosis
No Internal Compartments—membrane-bound organelles
Cell Membrane
Has Internal Compartments—membrane-bound organelles
Ribosomes
Earliest cells
Cells evolved later
Smaller ribosomes
Larger ribosomes