Cell Structures (Edexcel IGCSE Biology)

Spec point — 2.2 · describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuole

Cell Structures

• Cells are surrounded by a cell membrane, which separates them from their external environment

• Inside the cell membrane is the cytoplasm, a jelly-like substance of water with dissolved substances

• Eukaryotic cells have organelles within the cytoplasm

  • Organelles are sub-cellular structures that carry out specific functions within the cell

• Within the cytoplasm of eukaryotic cells the following organelles are present:

  • Nucleus

  • Ribosomes

  • Mitochondria

    • Watch out for the difference between the terms 'mitochondria' and 'mitochondrion'
    • Mitochondrion is used to refer to one organelle
    • Mitochondria is used to refer to more than one organelle eg. muscle cells contain many mitochondria

• Plant cells contain the following additional structures:

  • Cell wall
  • Chloroplasts
  • Permanent vacuole

• When viewed under a microscope, the structures inside a plant cell are visible

• Some cellular structures, like ribosomes and mitochondria, are too small to be viewed under a light microscope but are visible under an electron microscope

Cell Structures & Functions

Spec point — 2.3 · describe the functions of the nucleus, cytoplasm, cell membrane, cell wall, mitochondria, chloroplasts, ribosomes and vacuole

Cellular Structures & Functions Table