The document discusses cell structure and function. It covers the cell theory, basic structures of the cell including the plasma membrane and organelles, and functions of the cell like communication and metabolism. It describes limits to cell size and provides details on the fluid mosaic model of the plasma membrane. It also summarizes the structure and roles of various organelles and discusses cell division and the life cycle.

1. Chapter 3 - Cell Structure

4. Limits to Cell Size: Why small is better! Surface area of a cell is proportional to the square of its diameter. Volume is proportional to the cube of its diameter. Thus, for any increase in diameter of the cell, the volume increases faster than surface area. E.g. Small Cell of 10  m diameter SA = 10  m x 10  m x 6 = 600  m 2 Vol = 10  m x 10  m x 10  m =1000 2  m --------------------------------------------------------- Large Cell of 20  m diameter SA = 20  m x 20  m x 6 = 2,400  m 2 Vol = 20  m x 20  m x 20  m =8000 2  m -------------------------------------------------------- Note, that the larger cell has 8 times as much cytoplasm needing nourishment and waste removal, but only 4 times as much membrane surface through which wastes and nutrients can be exchanged.

16. Membrane Junctions: Tight Junction Figure 3.5a

17. Membrane Junctions: Desmosome Figure 3.5b

18. Membrane Junctions: Gap Junction Figure 3.5c

24. Endomembrane System

25. Endoplasmic Reticulum

28. Role of the Golgi Apparatus Figure 3.21

34. Motor Molecules Figure 3.25a