*after reading, take quiz before 8 am on monday. Made up of one or more cells. Viruses are acellular (not composed of cells) They are protein coat with genetic material (rna) Do not acquire energy from the environment or respond to environmental stimuli. Eukarya is the largest domain and contain nuclei. Bacteria and archaea are domains that do not have a nucleus. All three domains of life have a common ancestor. Archaea and eukarya are closer related than bacteria. Archaea and bacteria can live everywhere, including extreme environments. Nucleotide pairing in dna forms a double helix. During replication, two strands of dna separate. Each strand acts as the template for a. Includes phosphate group, nitrogenous base, and sugar backbone. new strand, in accordance with base pairing rules. After replication, each dna double helix has one old and one new strand. Errors in dna replication can introduce mutations and create genetic variation. Composed of amino acids, joined together by peptide bonds.