1. The cellular level of anatomical organization
Anatomy and Physiology
Brief history of cell theory
Cell membrane structure
Transport into /out of cell
Transport within the cell
Important organelles

2. Cell Theory:
1. All living things are made
of one or more cells
2. Cells are the basic units of
structure and function in
organisms
3. All cells arise from existing
cells

3. Development of the cell theory:
Robert Hooke in 1663, observed cork (plant): named the cell
Robert Brown observed and named nucleus
Theodor Schwann in 1800’s states: all animals are made of cells

4. Development of the Cell Theory
Matthias Schleiden in 1800’s states: all plants are made of cells
Louis Pasteur’s work with bacteria ~ 1860 disproved idea of spontaneous
generation (living things from nonliving)
Rudolf Virchow observes cells dividing and states all cells come from
preexisting cells

5. A cell is the simplest structural and functional unit of life.
There are no smaller subdivisions of a cell or organism that,
in themselves, are alive.
An organism’s structure and all of its functions are ultimately
due to the activities of its cells.
Importance of Cell Theory

6. Importance of Cell Theory
Cells come only from preexisting cells, not from nonliving matter. All life,
therefore, traces its ancestry to the same original cells.
Because of this common ancestry, the cells of all species have many
fundamental similarities in their chemical composition, and metabolic and
physiological mechanisms.

7. Why Cells are Small

8. Small cells are more efficient
Surface area to volume ratio must
remain high for materials to easily
reach all parts of the cell

10. Cell Membrane Structure and Transport

11. Cell Membrane
•Defines cell boundaries
•Controls interactions with other cells
•Controls passage of materials in and out of cell (contributes to homeostasis)
• Fluid-Mosaic model

13. Fluid Mosaic Model of Membranes

14. Membrane Proteins

15. Membrane Fluidity

16. Membrane Permeability
•Cell membranes are selectively permeable (semi-permeable)
•Some solutes cross the membrane freely, some cross with assistance, and
others do not cross at all.

19. The diffusion of water molecules through a selectively permeable membrane
Osmosis will continue as long as there are more water molecules on one side
of the membrane (“osmotic pressure”)
Water will continue to diffuse until there are equal numbers of molecules inside
and outside the cell (“osmotic balance”)
Osmosis

20. 60% H2O 90% H2O

21. Water will move out of to the left
across the membrane until osmotic
balance has been reached

23. 100% H2O
80% H2O

24. 90% H2O
90% H2O

25. 75% H2O
90% H2O
Water leaves
the cell and it
shrinks. This is
called
plasmolysis in
plant cells

27. Facilitated Diffusion
Involves carrier or channel proteins to transport substances that
otherwise could not pass the phospholipid bilayer (because of their
polarity or charge, like ions)

28. Active Transport and ATP Powered Pumps
Animal cells contain membrane vesicles
called lysosomes, filled with enzymes that
can degrade proteins, lipids, nucleic acids,
and other biomolecules. These enzymes
are most effective at acid pH, and it can be
experimentally shown that the pH inside
lysosomes is about 5.0, whereas the pH of
the cell cytoplasm is close to 7.0. The
diagram (at right) illustrates one lysosome
inside a cell.

31. Endocytosis Exocytosis