Cells

(Cooper, 1997 p .8-12)

The cell is the basic living unit of organization for all organisms.

Cell Theory - (middle of the nineteenth century)

All living organisms are composed of cells.
Cells are the functional units of life.
Cells can arise only from pre-existing cells.

What are the essential parts of the most simple living cell?

Cell membrane. Fig. 1
Cell wall. Fig. 2
Genetic material. (Mycoplasma)
Genetic material -> catalyst
(RNA catalyst not regulated. Protein catalyst can be regulated.)
Metabolism (get energy -> grow & divide)

Why are cells limited in size?

Concentration
Diffusion
Limitions can be overcome by cytoplasmic streaming

Exercise:
Move the cursor over the figure below (or click here to see a larger view) to determine the names and characteristic components of bacterial (a.), animal (b.), and plant (c.) cells. Hold the mouse down over highlighted components to gather further information. Collect and catalog the similarities and differences for each of the characteristics listed in Fig. 3?

Exercise Summary

References:
Cooper, Geoffrey M. (1997) The Cell: A Molecular Approach; ASM Press, Washington, D.C. / Sinauer Associates, Inc., Sunderland, MA.

Alberts, B., Bray, D., Johnson, A., Lewis, J., Raff, M., Roberts, K., and Walter, P. (1998) Essential Cell Biology, An introduction to the Molecular Biology of the Cell; Garland Publishing, Inc., New York / London.