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📚 > Physiology > General Physiology > Cells and Molecules_>

Introduction to the Cell

  • Cell is the smallest living unit in the body.

Structure of the Cell: Components and Their Main Functions

  • Cell Membrane: Makes the wall of the cell.

  • Cytoplasm: Base material that fills the cell. Organelles are suspended in it.

  • Nucleus: Control center of the cell. Contains genetic information.

  • Endoplasmic Reticulum: Site for protein synthesis and metabolic reactions.

  • Ribosome: Synthesise proteins.

  • Golgi apparatus: Further processing of synthesized proteins.

  • Secretory vesicles: Store secretory proteins.

  • Peroxisomes: Degrades toxic substances.

  • Lysosome: Digestive system of the cell.

  • Mitochondria: Powerhouse of the cell.

  • Cycockeletal: Structural support & cell movement.

Activities Going on Inside the Cell

Common Activities
  • are mostly common for all cells in the body.

  • e.g. activities related to cell's own survival i.e. maintaining a constant intracellular environment, taking in nutrients from surrounding, eliminating waste products, etc.

Special Activities
  • are the activities Related to cell's special functions in the body.

  • Examples of special functions of different cells:

  • White blood cells: Kill bacteria.

  • Muscle cells: Contract muscle.

  • Red blood cells: Transport oxygen.

  • Epithelial cells in the digestive tract: Secrete digestive enzymes.

  • The magnitude of different activities is controlled by gene expression.

  • If a cell need to perform certain activities, genes related to those activities are expressed in that cell.

  • Genes related to activities that are not required are not expressed.

Physiological Processes Involved in Performing Aforementioned Activities


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Cells and Molecules > ▶️ Cell Membrane
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