CELLS
Structure and Function
The cell is the basic unit of structure and function in a living organism.
COMMON CELL STRUCTURES
Cell Membrane
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This is the outermost living structure of the cell which is also referred to as the plasma
membrane or the plasmalemma
It consists of a bilayer of fat (lipid) and protein molecules
The cell membrane and the protoplasm comprise of the living material of the cell ( the
protoplasm consists of the nucleus and the cytoplasm with all its contents)
Function
The cell membrane acts as a regulator by selectively allowing the pass of certain substances
e.g., food materials and waste products in and out of the cell
Hence, it’s described as selectively permeable or partially permeable
In this way a constant environment is maintained within the cell
Cell Wall
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Found in plant cells, fungal and bacteria cells
In plant cells it is composed of cellulose. It is fully permeable (cannot control what enters or
leaves the cell), rigid non-living structure
Function
It gives shape, support, strength and protection to the plant cell