Chapter 3, part 1
An Introduction to The Cellular Level of Organization
Learning Objectives
List the main points of the cell theory.
Describe the chief structural features of the cell membrane.
Describe the organelles of a typical cell, and give their specific functions.
Summarize the process of protein synthesis.
Describe the various transport mechanisms used by cells, and relate this to the transmembrane potential.
Describe the cell life cycle, mitosis and cellular differentiation.
SECTION 3-1 An Introduction to Cells
The cell theory states:
Cells are the building blocks of all plants and animals
Cells are produced by the division of preexisting cells
Cells are the smallest units that perform all vital physiological functions
Each cell maintains homeostasis at the cellular level
Homeostasis at higher levels reflects combined, coordinated action of many cells
Figure 3.1 The Diversity of Cells in the Human Body
Cell biology
Cytology, the study of the structure and function of cells
The human body contains both somatic and sex cells
Figure 3.2 The Anatomy of a Representative Cell
A typical cell
Is surrounded by extracellular fluid, which is the interstitial fluid of the tissue
Has an outer boundary called the cell membrane or plasma membrane
SECTION 3-2 The Cell Membrane
Cell membrane functions include:
Physical isolation
Regulation of exchange with the environment
Structural support
Figure 3.3 The Cell Membrane
The cell membrane is a phospholipid bilayer with proteins, lipids and carbohydrates.
Membrane proteins include:
Integral proteins
Peripheral proteins
Anchoring proteins
Recognition proteins
Receptor proteins
Carrier proteins
Channels
Figure 3.4 Membrane proteins
Membrane carbohydrates form the glycocalyx
Proteoglycans
Glycolipids
Glycoproteins
