How do eukaryotic cells differ from bacteria and archaea?
Eukaryotic cells are more specialised cells within the Protista kingdom. They can be both unicellular and multicellular organisms. They have membrane bound organelles (chloroplast and mitochondria), and a nucleus, which contains long strands of DNA structured in chromosomes.
Bacteria (eubacteria) and archaea are unicellular organelles, which lack membrane bound organelles and a nucleus. They contain more primitive single long circular DNA called a chromosome that contains all of the genes necessary for maintenance, repair and growth. The location in cell called the nucleoid.
Unlike eukaryotic cells, archaea are known as extremophiles, and are found in unusual extreme environments. They are broken down into five groups: methanogens (use carbon dioxide and hydrogen in anoxic conditions, to produce methane), acidophiles (live in acidic environments, usually lower than pH 2), thermophiles (live in high temperatures, between 40 and 122 °C), psychrophiles (live in low temperatures between −20 °C and 10 °C) and halophiles (live in in locations of high salt concentrations).
Similarly to eukaryotic cells, bacteria (eubacteria) are commonly seen as ‘true’ bacteria and are more diverse than archaea. They are found nearly every were, from your gut to soil.