Cell Biology Fundamentals

Cell Definition and Structure

• The cell is the basic structural and functional unit of all forms of life.
• Every cell consists of cytoplasm enclosed within a membrane and contains various organelles, including:
  • Nucleus
  • Endoplasmic reticulum
  • Golgi apparatus
  • Cytoskeleton
  • Ribosome
  • Centrosomes

Cell Classification

• Cells are classified into two main types based on the presence of a nuclear membrane: Eukaryotic and Prokaryotic cells.

Cell Membrane

• The cell membrane is a double layer of phospholipids, which are amphiphilic (partly hydrophobic and partly hydrophilic).
• The cell membrane has two main functions:
  • Regulating the movement of materials into and out of the cell through endocytosis and exocytosis.
  • Allowing large molecules, microorganisms, and waste products to pass through.

Inclusions

• Inclusions are metabolically inert substances that are stored in the cell and released as needed.
• Examples of inclusions include:
  • Masses of organic chemicals
  • Lipids
  • Glycogen
  • Melanin (stored in skin and oral mucosa cells and responsible for pigmentation)
  • Residual bodies (spent lysosomes and their digested material)

Cell Division (Mitosis)

• Mitosis is a complex process involving many organelles of the cell.
• Mitosis occurs during tissue growth or regeneration and is dependent on the length of the individual cell's lifespan.

Learn about the basic structure and functions of cells, including their components and classification into Eukaryotic and Prokaryotic cells.