Structure of Eukaryotic Cells (AQA A Level Biology): Revision Note

The structure of eukaryotic cells

• Cell-surface membrane

  • Controls substance entry/exit

  • Composed of a phospholipid bilayer with embedded proteins

  • Read more about the cell surface membrane

• Nucleus

  • Contains linear DNA (protein-bound as chromosomes)

  • Nucleolus produces ribosomes

• Mitochondria

  • The site of aerobic respiration and ATP production

• Chloroplasts

  • The site of photosynthesis (in plants/algae)

  • Contains chlorophyll

• Golgi apparatus

  • Modifies and packages proteins and lipids

  • Forms vesicles e.g. lysosomes

• Lysosomes

  • Vesicles that contain hydrolytic enzymes for digesting worn-out organelles or pathogens

• Endoplasmic reticulum

  • Rough ER: Ribosome-covered and responsible for the synthesis and transport of proteins

  • Smooth ER: Synthesises and stores lipids and carbohydrates

• Ribosomes

  • The site of protein synthesis

    • 80S in eukaryotes and 70S in prokaryotes

• Cell wall

  • Provides strength/support

  • Made from

    • cellulose in plants

    • chitin in fungi

• Vacuole

  • Stores cell sap (in plants)

  • Helps maintain cell pressure and structure