Cells & Cell Structure

Definition of a Cell

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

Types of Cells

• Prokaryotic Cells: No nucleus (e.g., bacteria).


• Eukaryotic Cells: Nucleus present (plants, animals, fungi).

Cell Organelles and Functions

• Nucleus: Controls cell activities, stores DNA.
• Mitochondria: Site of respiration; produces energy (ATP).
• Ribosomes: Site of protein synthesis.
• Endoplasmic Reticulum (ER): Rough ER: protein synthesis; Smooth ER: lipid synthesis.
• Golgi Apparatus: Modifies, packages, and transports proteins.
• Chloroplast: Site of photosynthesis in plant cells.
• Vacuole: Storage of water, nutrients, and waste; large in plant cells.
• Lysosomes: Contains enzymes for digestion of waste.
• Cell Membrane: Controls entry and exit of substances.
• Cell Wall: Provides structure and protection (plants only).

Differences Between Plant and Animal Cells

Practice Questions

• Define a cell and state the cell theory. (6 marks)
• Differentiate between prokaryotic and eukaryotic cells. (4 marks)
• List ten organelles of a plant cell and state their functions. (10 marks)
• Draw and label a plant and an animal cell. (5 marks)
• Explain three differences between plant and animal cells. (3 marks)
• Short answer: What is the function of the mitochondria? (2 marks)