What Is A Cell Made Up Of? What Is The Structural Organisation Of A Cell?

Key Notes:

🔬 What is a Cell Made Up Of?

Basic Unit of Life:

• A cell is the basic structural and functional unit of life.
• All living organisms are made up of cells.

Cell Membrane (Plasma Membrane):

• It surrounds the cell and protects it.
• Controls the movement of substances in and out of the cell.
• It is semi-permeable (allows some materials to pass).

Cytoplasm:

• A jelly-like fluid inside the cell.
• It holds all the organelles and allows movement within the cell.

Nucleus:

• The control center of the cell.
• Contains DNA (genetic material).
• Surrounded by the nuclear membrane.
• Directs all activities of the cell like growth, reproduction, etc.

Cell Organelles (tiny organs inside the cell):

• Mitochondria – Powerhouse of the cell (releases energy).
• Endoplasmic Reticulum (ER) – Transports substances.
• Rough ER has ribosomes; Smooth ER does not.
• Ribosomes – Make proteins.
• Golgi Apparatus – Packs and sends proteins.
• Lysosomes – Clean up waste (suicide bags).
• Vacuoles – Store water, food, or waste.
• Plastids (only in plant cells) – Chloroplasts help in photosynthesis.
• Centrosome (only in animal cells) – Helps in cell division.

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🧱 What Is the Structural Organisation of a Cell?

Three Main Parts:

• Cell Membrane
• Cytoplasm
• Nucleus

Types of Cells:

• Prokaryotic Cells: Simple cells without a true nucleus (e.g., bacteria).
• Eukaryotic Cells: Complex cells with a true nucleus (e.g., plant and animal cells).

Plant Cell vs. Animal Cell:

Feature	Plant Cell	Animal Cell
Cell Wall	Present	Absent
Vacuole	Large and central	Small or absent
Chloroplast	Present (for photosynthesis)	Absent
Shape	Rectangular	Round/irregular

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🧠 Quick Facts:

• Cells come in different shapes and sizes.
• Unicellular organisms (like amoeba) have only one cell.
• Multicellular organisms (like humans) have many cells organized into tissues, organs, and systems.