๐ > 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.
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
Endocytosis, exocytosis, etc.
Cell movement.
Changing the shape of cell.
Adaptation in response to changing environment.
Cell death.