ASBiologyAQARevision NotesCell StructureCell StructureStructure of Eukaryotic Cells

Structure of Eukaryotic Cells (AQA AS Biology): Revision Note

Exam code: 7401

Lára Marie McIvor

Written by: Lára Marie McIvor

Reviewed by: Ruth Brindle

Updated on

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

Diagram showing cell and detailed view of cell membrane with labels for nucleus, proteins, cytoplasm, and outside cell environment.
The cell surface membrane

  • Nucleus

    • Contains linear DNA (protein-bound as chromosomes)

    • Nucleolus produces ribosomes

Diagram of a cell nucleus and endoplasmic reticulum, labelled parts include nucleolus, chromatin, nuclear envelope, ribosomes, and nuclear pore.
The nucleus

  • Mitochondria

    • The site of aerobic respiration and ATP production

Diagram of a mitochondrion showing outer membrane, inner membrane, cristae, and matrix, with labels and blue areas indicating internal structures.
The mitochondria

  • Chloroplasts

    • The site of photosynthesis (in plants/algae)

    • Contains chlorophyll

Diagram of a chloroplast showing labelled parts: thylakoid, lamella, granum, ribosome, stroma, lipid droplet, membranes, intermembrane space, starch granule, DNA.
The chloroplast

  • Golgi apparatus

    • Modifies and packages proteins and lipids

    • Forms vesicles e.g. lysosomes

Diagram of the Golgi apparatus with labels: cis face, cisternae, lumen, trans face, incoming transport vesicle, secretory vesicle, newly forming vesicle.
The Golgi apparatus

  • Lysosomes

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

Diagram of a cell showing a labelled membrane, enzymes illustrated as orange shapes inside, and transport proteins on the surface.
The lysosome

  • Endoplasmic reticulum

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

    • Smooth ER: Synthesises and stores lipids and carbohydrates

Diagram of a cell showing rough and smooth endoplasmic reticulum, nuclear envelope, nucleus, and ribosomes, with labelled sections in different colours.
The endoplasmic reticulum

  • Ribosomes

    • The site of protein synthesis

      • 80S in eukaryotes and 70S in prokaryotes

Diagram of a ribosome with labelled large and small subunits and mRNA strand illustrating protein synthesis.
The ribosome

  • Cell wall

    • Provides strength/support

    • Made from

      • cellulose in plants

      • chitin in fungi

Diagram of a plant cell wall with labels for middle lamella, pectin, hemicellulose, plasma membrane, cellulose microfibril, and cell wall.
The cell wall

  • Vacuole

    • Stores cell sap (in plants)

    • Helps maintain cell pressure and structure

Diagram of a plant cell's central vacuole, labelled with cell sap, tonoplast, and central vacuole, indicating internal components.
The vacuole

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    Author
    Reviewer
    Lára Marie McIvor

    Author: Lára Marie McIvor

    Expertise: Biology, Psychology & Sociology Subject Lead

    Lára graduated from Oxford University in Biological Sciences and has now been a science tutor working in the UK for several years. Lára has a particular interest in the area of infectious disease and epidemiology, and enjoys creating original educational materials that develop confidence and facilitate learning.

    Ruth Brindle

    Reviewer: Ruth Brindle

    Expertise: Biology Content Creator

    Ruth graduated from Sheffield University with a degree in Biology and went on to teach Science in London whilst also completing an MA in innovation in Education. With 10 years of teaching experience across the 3 key science disciplines, Ruth decided to set up a tutoring business to support students in her local area. Ruth has worked with several exam boards and loves to use her experience to produce educational materials which make the mark schemes accessible to all students.