summary – Chapter 5 – class 9

Cell as the Fundamental Unit: The cell is the basic structural and functional unit of life.
Plasma Membrane: Cells are enclosed by a plasma membrane composed of lipids and proteins. It regulates the movement of materials between the cell’s interior and the outer environment.
Cell Wall in Plant Cells: In plant cells, a cell wall composed mainly of cellulose is located outside the plasma membrane. It provides structural support and prevents bursting in hypotonic environments.
Nucleus: In eukaryotic cells, the nucleus is separated from the cytoplasm by a double-layered membrane and directs the cell’s life processes.
Endoplasmic Reticulum (ER): Functions as both a passageway for intracellular transport and a manufacturing surface.
Golgi Apparatus: Consists of stacks of membrane-bound vesicles involved in the storage, modification, and packaging of substances manufactured in the cell.
Plastids: Membranous organelles in plant cells, including chloroplasts for photosynthesis and leucoplasts for storage.
Central Vacuole: Large vacuole in plant cells that helps maintain cell turgidity and stores important substances, including wastes.
Prokaryotic Cells: Lack membrane-bound organelles, have chromosomes composed of nucleic acid, and small ribosomes.
Cell Division: Cells divide for growth, replacing dead cells, and forming gametes for reproduction.