Prokaryotes vs Eukaryotes

• Cell Types 


  •Evolutionarily speaking, there are two types of cell.

  •Prokaryotic ‘before nucleus’

  •Eukaryotic ‘after nucleus’

  Eukaryotic cells are larger and more complex than prokaryotic cells.
• Cells

  Prokaryotes (Unicellular/Single Celled)

  • Bacteria
  • Archaea
  • Prokaryotic cells refer to the cell
  • Prokaryote refer to the organism

  Eukaryotes

  • Eukarya
  • Protists
  • Plants
  • Animals
  • Fungi
• Prokaryotic Cells


  •Simple, very small (mostly from 1µm-10µm), unspecialised cells

  •Have no nucleus or membrane-bound organelles.

  •The genetic material (DNA) is organised into one circular chromosome.

  •Exist in very primitive organisms, such as bacteria, and almost always single-celled or unicellular organisms.
• Multicellular Prokaryotes

  • Some bacteria exhibit multicellular forms
  • These are called actinomyces and cyanobacteria
• Prokaryotic Cells 


  •Cytoplasm consists of fluid (cytosol) with internal structures inside.

  •Ribosomes are (non membrane-bound) organelles that is where protein synthesis (creation) occurs.

  •Cell membrane is surrounded by a cell wall.

  •Small circular rings of DNA called plasmids often float in cytoplasm.
• Eukaryotic Cells 


  •These cells are larger (mostly from 10µm-100µm).

  •Are well-organised cells with membrane-bound organelles.

  •Found in all plants, animals and fungi (all multicellular organisms).

  •Many unicellular eukaryotes exist (e.g. protozoa & algae).

  •Has a nucleus containing multiple linear chromosomes.

  Membrane-bound organelle = organelle with it’s own membrane (enclosure) to keep fluids separate to cytoplasm.
• Prokaryotic Cells Organelles

  • Cytoplasm
  • Flagellum
  • Ribosomes
  • Nucleoid (DNA)
  • Plasma membrane
  • Cell wall
  • Capsule
  • Plasmid
  • Pili
• Eukaryotic Cells

  • Ribosomes
  • Golgi apparatus
  • Plasma membrane
  • Mitochondrion
  • Lysosome
  • Cytoskeleton
  • Microfilaments
  • Intermediate filaments
  • Microtubules
  • Microvilli
  • Peroxisome
  • Centrosome
  • Flagellum
  • Endoplasmic Reticulum
  • Rough ER
  • Smooth ER
  • Nucleus
  • Chromatin
  • Nucleolus
  • Nuclear envelope
• Eukaryotic Cells Organelles not in Animal Cells

  • Chloroplasts
  • Central vacuole and tonoplast
  • Cell wall
  • Plasmodesmata
• Prokaryotic cells


  Date back in the fossil record to 3.4 - 3.5 billion years ago
• Eukaryotic cells


  Earliest date back to 2.7 billion years ago
• Prokaryotic cells are old and more primitive
• Theories suggest that a large prokaryotic cell swallowed a smaller prokaryotic cell


  1. Smaller prokaryotic cell survived

  2. Formed a symbiotic relationship (where they both benefit)
• Mitochondria and chloroplasts


  Smaller prokaryotic cells that became these organelles
• Photosynthetic prokaryotic cells


  Became chloroplasts
• Aerobic prokaryotic cell


  Became the mitochondria
• Features of Mitochondria and Chloroplasts 


  •Through the use of electron microscopy:

  •Both have their own short and circular DNA, which do not match the DNA sequencing of the nucleus.

  •Both contain ribosomes, like prokaryotic cells, which produce proteins.

  •Eukaryotic cell organelles resemble prokaryotic cells (look-a-like).

  •Both organelles reproduce via binary fission, the same reproductive method as bacteria.

  •Both contain cell membranes, like prokaryotic cells.
• Chloroplast Diagram

  • Intermembrane space
  • Stroma lamellae
  • Thylakoid
  • Lumen
  • Inner membrane
  • Outer membrane
  • Granum
  • Stroma
• Mitochondria Diagram

  • ATP synthase particles
  • Matrix
  • Intermembrane space
  • Cristae
  • Ribosomes
  • Granules
  • Deoxyribonucleic acid (DNA)
  • Outer membrane
  • Inner membrane
• Tip


  •If asked in a question if eukaryotic cells have circular DNA, the answer is yes, because their mitochondria and chloroplasts have it.

  •The eukaryotic cell would still have linear strand of DNA in the nucleus.