Cell Structure Revision Notes

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Cell Structure Revision Notes

Structure of a typical plant cell:

  • Contains cytoplasm and a nucleus. Rough and smooth ER found in the cytoplasm, along with Golgi. Mitochondria produce ATP
  • Nucleus is surrounded by a double membrane
  • Organelles in the cytoplasm are surrounded by one membrane

Plant cell wall:

  • Cell wall gives strength and support- made up of insoluble cellulose
  • In cellulose, the monomer units are beta glucose and held together by 1,4 bonds, where one monomer has to be turned around so the bonding can take place
  • This linking of beta glucose molecules means that the hydroxyl groups stick out on both sides of the molecule
  • This means hydrogen bonds can form between the partially positively charged hydrogen atoms of the hydroxyl groups and the negatively charged oxygen atoms in other areas of the glucose molecules
  • This is known as cross linking and it holds neighbouring chains firmly together
  • In the cell wall, cellulose molecules form microfibrils, which are laid down in layers held together by a matrix.
  • Contains a middle lamella which is made of pectin which helps hold adjacent cells together
  • Plasmodesmata are involved in cell to cell transport. Both cell walls are absent, lined with membrane and have a cytoplasm filled channel with ER extending through
  • Pits are also involved in cell to cell transport. Their secondary cell wall is absent and they are lined with membrane.

Plant cell organelles:


  • Enable plants to produce their own food
  • Large organelles- biconvex shape, 4-10mm long
  • Double membranes are present
  • Many internal membranes, some are arranged as stacks called grana
  • Loop of DNA found in the stroma


  • Double membrane present
  • Contains one type of starch called amylopectin
  • Amylopectin sometimes shows concentric rings
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  • Surrounded by a single membrane called the tonoplast
  • Contains cell sap

Plant stem structure and function:


  • Outer layer of the stem
  • Secrete cutin, a waxy substance that helps to prevent water loss from the stem surface and protects against the entry of pathogens
  • Cells may also form hairs, either as an extension of a single cell or from several modified epidermal cells

Parenchyma and collenchyma:

  • Parenchyma are unspecialised cells but can be modified to make them suitable for storage and photosynthesis
  • Collenchyma cells have thick primary cell walls which are even thicker at ...

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