Electron Microscopy of Plant Cells (Edexcel International AS Biology): Revision Note

Electron Microscopy of Plant Cells

• It is important to be able to recognise various plant organelles from electron microscope images

  • Chloroplast

    • Has distinctive stacks of thylakoids

    • Double membrane

    • Has a roughly oval shape

    • Larger than mitochondria

    • Indicates the cell is a plant cell

  • Nucleus

    • Has a nuclear membrane and a dark nucleolus within

    • It has a roughly spherical shape

  • Vacuole

    • Occupies a large space within a cell

    • Often shows up as a very light shade (white) within an electron micrograph

    • Indicates the cell is a plant cell

  • Cell wall

    • Located around the perimeter of the cell

  • Mitochondria

    • Roughly oval-shaped

    • Double membrane

    • Sometimes observed with visible cristae (foldings of the inner membrane)

  • Cell membrane (plasma membrane)

    • Located just inside the cell wall, pressed against it

    • Appears as a thin, dark line following the inner edge of the cell wall

    • Often difficult to distinguish from the cell wall at low magnification, as the two run parallel and close together

    • Encloses the cytoplasm and all the cell's content

TEM electron micrograph of a plant cell showing key features