<span>Similarities and Differences There are many similarities and differences between the three domains. Bacteria and Archaea differ in how they gain energy. Bacteria gain energy either by being phototrophs, lithotrophs or organotrophs. One similarity between domain Archaea and domain Bacteria is that they both contain only prokaryotes while domain Eukarya only contains eukaryotes. Domain Archaea is the only domain that is sensitive to antibiotics. Another similarity between domain Bacteria and domain Eukarya is that Methionine is the first amino acid seen during protein synthesis while in domain Archaea, the first amino acid is Formylmethionine. The last major similarity between domain Archaea and domain Bacteria is that they do not contain any organelles while domain Eukarya does. A difference between all three domains is what their cell walls contain. A cell wall in domain Archaea has peptidoglycan. The organisms that have a cell wall in domain Eukarya, will have a cell wall made up of polysaccharides.</span>
