2.3 Eukaryotic Cells

2.3.1  Draw and label a diagram of the ultrastructure of a liver cell as an example of an animal cell

                                      2D Representation                                                                                                                 3D Representation

2.3.2  Annotate the diagram from 2.3.1 with the functions of each named structure

Cell Membrane:  Semi-permeable barrier that controls the entry and exit of substances

Cytosol:  The fluid portion of the cytoplasm (does not include the organelles or other insoluble materials)

Nucleus:  Contains hereditary material (DNA) and thus controls cell activities (via transcription) and mitosis (via DNA replication)

Nucleolus:  Site of the production and assembly of ribosome components

Ribosome:  Complexes of RNA and protein that are responsible for polypeptide synthesis (eukaryotic ribosomes are larger than prokaryotes - 80S)

Mitochondria:  Site of aerobic respiration, which produces large quantities of chemical energy (ATP) from organic compounds

Golgi Apparatus:  An assembly of vesicles and folded membranes involved in the sorting, storing and modification of secretory products

Lysosome:  Site of hydrolysis / digestion / breakdown of macromolecules

Peroxisome:  Catalyses breakdwon of toxic substances like hydrogen peroxide and other metabolites

Centrioles:  Microtubule-organising centres involved in cell division (mitosis / meiosis and cytokinesis)

Endoplasmic Reticulum:  A system of membranes involved in the transport of materials between organelles

  • Rough ER:  Studded with ribosomes and involved in the synthesis and transport of proteins destined for secretion
  • Smooth ER:  Involved in the synthesis and transport of lipids and steroids, as well as metabolism of carbohydrates

2.3.3  Identify the structures in 2.2.1 in electron micrographs of a liver cell

Electron Micrograph of a Liver Cell

2.3.4  Compare prokaryote and eukaryote cells


  • Both have a cell membrane
  • Both contain ribosomes
  • Both have DNA and cytoplasm


2.3.5  State three differences between plant and animal cells

                                         Labelled Diagram of a Generalised Plant Cell

2.3.6  Outline two roles of extracellular components


The cell wall in plants is made from cellulose secreted from the cell, which serves the following functions:

  • Provides support and mechanical strength for the cell (maintains cell shape)
  • Prevents excessive water uptake by maintaining a stable, turgid state
  • Serves as a barrier against infection by pathogens


The extracellular matrix (ECM) is made from glycoproteins secreted from the cell, which serve the following functions:

  • Provides support and anchorage for cells
  • Segregates tissues from one another
  • Regulates intercellular communication by sequestering growth factors