Purpose and Perspective of the Chapter This chapter introduces the basic functions of the human cell to serve as background as students proceed to learn about nutrition and metabolism within the human body. Chapter Objectives The following objectives are addressed in this chapter: 1.1 Identify cellular components and their functions. 1.2 Describe the roles of cell receptors and enzymes. 1.3 Explain the mechanisms by which enzymatic reactions are regulated. 1.4 Discuss the need for and pathways involved in apoptosis. 1.5 Describe how energy is released and utilized in chemical reactions. [return to top] Chapter Outline I. Introduction 1. This chapter provides a brief review of the basics of a cell, including cellular components, biological energy, and an overview of a cell’s natural life span. 2. Key Terms a. Cells—basic living, structural, and functional units of the human body b. Eukaryotic cells—multicellular organisms c. Prokaryotic cells—primitive cells d. Plasma membrane—sheetlike structure that encapsulates and surrounds the cell, allowing it to exist as a distinct unit 3. Figures and Tables a. Figure 1.1—three-dimensional depiction of a typical mammalian liver cell II. Components of Cells A. Plasma Membrane 1. Sheetlike structure that encapsulates and surrounds the cell. It is asymmetrical and considered to be a fluid structure 2. Key Terms a. Hydrophobic—molecule or part of molecul