Cell Anatomy PDF

# 3. THE CELL The cell is the anatomical and physiological unit of living beings. It is the anatomical unit because it is the simplest form of life of an organism, and it is the physiological unit because it performs all the necessary tasks to remain alive (nutrition, reproduction, response to stim...

# 3. THE CELL The cell is the anatomical and physiological unit of living beings. It is the anatomical unit because it is the simplest form of life of an organism, and it is the physiological unit because it performs all the necessary tasks to remain alive (nutrition, reproduction, response to stimuli). The life of an organism is the sum of the vital activities of its cells. # 3.1 CELLULAR ANATOMY: The cell is composed of: * **Plasma membrane or cellular membrane:** It is a flexible covering that envelops the cell. It is formed by a double layer of lipids and proteins inserted into it, and some carbohydrates. Its functions are: * Separating the cell from its environment, maintaining constant physical and chemical conditions. * Controlling the passage of substances between the cell and the surrounding medium (selective permeability). **Diagram Description:** The diagram shows a cross-section of a cell membrane. The membrane appears as a double layer (bilayer) with various components embedded within it. Different types of molecules are clearly labeled, including phospholipids (forming the main bilayer), cholesterol molecules, and different types of proteins (some spanning the entire membrane, others embedded on one side). Carbohydrate chains, collectively known as glycoproteins, are also seen attached to some membrane proteins. The diagram clearly distinguishes the inside of the cell from the exterior environment.