Seeley's Anatomy & Physiology - Chapter 3 - Cells | Questions and Answers with complete solution

organelles - These are specialized structures within a cell which perform specific functions. Also know as "little organs". cytoplasm - The living material surrounding the nucleus. It contains many types of organelles and is enclosed by the cell membrane, or plasma membrane. four main functions of cells - 1. Cell metabolism and energy use 2. Synthesis of molecules 3. Communication 4. Reproduction and inheritance cell membrane - The outermost component of a cell. It encloses the cytoplasm and forms the boundary between material inside the cell and material outside it. Also called the plasma membrane. plasma membrane - The outermost component of a cell. It encloses the cytoplasm and forms the boundary between material inside the cell and material outside it. Also called the cell membrane. extracellular - Substances outside of the cell. intracellular - Substance inside of the cell. The cell membrane is made up of what materials? - The major molecules are phospholipids and proteins. But, it also contains other molecules such as cholesterol and carbohydrates. fluid-mosaic model - The model that characterizes the structure of the cell membrane. The membrane is composed of a bilayer of phospholipids and cholesterol with proteins "floating" in the membrane. The nonpolar hydrophobic region of each phospholipid molecule is directed to the center ofthe membrane, and the polar hydrophillic region is directed toward the fluid environment either outside or inside the cell. membrane channels - large protein molecules that extend from one surface of the plasma membrane to the other