4BI1

Cell Structure

Structures and Functions in Living Organisms · 6 question types

Practise

Exam Frequency Analysis

Past paper frequency (2018 to 2024)

This topic accounts for approximately 18% of your exam marks.

stable
Very High
Stable18%

Cell structure and organelle function appear on nearly every paper; one of the highest-frequency topics.

A side-by-side comparison

FeatureAnimal cellPlant cell
NucleusYesYes
CytoplasmYesYes
Cell membraneYesYes
MitochondriaYesYes
RibosomesYesYes
Cell wallNoYes (cellulose)
ChloroplastsNoYes (in leaf and stem cells)
Permanent vacuoleNo (only small temporary vacuoles)Yes, large and central
Overall shapeIrregular, flexibleFixed shape (rectangular or "box-like") because of the cell wall
Storage carbohydrateGlycogenStarch (in roots and tubers) or sucrose (in fruit)

Why plants have what they have

Plants need three extra structures that animals do not:

  • A cell wall: plants do not have a skeleton, so each individual cell has to be rigid. The cellulose wall gives the plant body its shape and stops the cell from bursting when water rushes in.
  • Chloroplasts: plants make their own food by photosynthesis, so they need an organelle that contains chlorophyll to capture light energy. Animals are heterotrophs and eat ready-made food, so they have no need for chloroplasts.
  • A large permanent vacuole: plants control their support hydraulically. A full vacuole pushes outwards on the cell wall, making the cell turgid and keeping the plant standing up. When the vacuole loses water, the cell becomes flaccid and the plant wilts.
Labelled animal cell on the left and labelled plant cell on the right, showing that the plant cell has a cell wall, chloroplasts and a permanent vacuole that the animal cell lacks
Source: Eukaryotic Organism Features by Save My Exams
Exam tip

Animal vs plant cells

Stating which structures are in plant cells but not animal cells comes up, so you need to know plant cells have a cell wall (cellulose), a large permanent vacuole, and chloroplasts, while animal cells have none of these three. Chloroplasts are absent from root cells, so qualify with "leaf/stem cells" if asked about plant cells in general.