1. Discovery of Cell
Cells were first discovered by Robert Hooke in 1665. The Cell Theory, proposed by
Schleiden and Schwann, states that all plants and animals are composed of cells and that the
cell is the basic unit of life.
2. Plasma Membrane and Cell Wall
- Plasma Membrane: Selectively permeable membrane that regulates movement
of substances via Diffusion and Osmosis.
- Cell Wall: Rigid outer covering found only in plant cells, made of
cellulose.
3. Nucleus and Cytoplasm
Nucleus: The control center of the cell containing genetic material (DNA).
Prokaryotic cells lack a defined nuclear region, while Eukaryotic cells have a
nuclear membrane.
Cytoplasm: The fluid content inside the plasma membrane containing
organelles.
4. Cell Organelles
- Mitochondria: Powerhouse of the cell (ATP production).
- Ribosomes: Sites of protein synthesis.
- Lysosomes: Suicide bags (digestive enzymes).
- Plastids: Found only in plant cells (e.g., Chloroplasts for
photosynthesis).