2.3 Eukaryotic cells

Prokaryotes vs. Eukaryotes Prokaryotes contain only a

nucleoid and no organelles.

Prokaryotes are simpler and appear earliest in Earth’s fossil records.

Size: 1 – 3 μm

Eukaryotes contain a true nucleus and membrane-bound organelles.

Eukaryotes are more complex, thus appear later. Symbiont theory: smaller unicellular organisms were engulfed and became part of larger ones, eventually specialising to become organelles within the cell. Evidence: comparable in size and have their own DNA (mitochondria)

Size: 10 – 100 μm

Prokaryotes vs. Eukaryotes