A-Level Biology AQA 7402

2.1.2: Structure of prokaryotic cells and of viruses

#2.1.2.1

Prokaryotic cells are much smaller than eukaryotic cells. They also differ from eukaryotic cells in having:

  • cytoplasm that lacks membrane-bound organelles
  • smaller ribosomes
  • no nucleus; instead they have a single circular DNA molecule that is free in the cytoplasm and is not associated with proteins
  • a cell wall that contains murein, a glycoprotein.
#2.1.2.2

In addition, many prokaryotic cells have:

  • one or more plasmids
  • a capsule surrounding the cell
  • one or more flagella.

Details of these structural differences are not required.

#2.1.2.3

Viruses are acellular and non-living. The structure of virus particles to include genetic material, capsid and attachment protein.

2.1.1
Structure of eukaryotic cells
2.1.3
Methods of studying cells
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