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Biology AS Edexcel Snab Revision

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Exam code:8BN0

Prokaryotic Cells: Structure

  • Animal and plant cells are types of eukaryotic cells, whereas bacteria are a type of prokaryote

  • Prokaryotic cells are much smaller than eukaryotic cells 

  • They also differ from eukaryotic cells in having

    • cytoplasm that lacks membrane-bound organelles

    • Ribosomes that are smaller (70 S) than those found in eukaryotic cells (80 S)

    • No nucleus, instead having a single circular bacterial chromosome that is free in the cytoplasm and is not associated with proteins

    • A cell wall that contains the glycoprotein murein 

      • Murein is sometimes known as peptidoglycan

  • In addition, many prokaryotic cells also have the following structures

    • Loops of DNA known as plasmids

    • Capsules

    • Flagella (singular flagellum)

    • Pili (singular pilus)

    • A cell membrane that contains folds known as mesosomes

Additional Prokaryotic Structures Table

additional-prokaryotic-structures-table
Cell Components- Prokaryotic cell

Bacteria are prokaryotic cells

Prokaryotes vs eukaryotes

  • There are a number of important structural and physiological differences between prokaryotic and eukaryotic cells

  • These differences affect their metabolic processes and how they reproduce

Comparison of Prokaryotic and Eukaryotic Cells Table

Comparison of Prokaryotes & Eukaryotes table

Examiner Tips and Tricks

You will need to know all the differences between prokaryotic and eukaryotic cells; remember that not all of the structures mentioned here are present in all prokaryotic cells

Remember that size is not a structural feature so if you are asked for a structural difference between a prokaryotic and eukaryotic cell don’t include size in your answer.

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