BIO 111 Chapter Notes - Chapter 19: Horizontal Gene Transfer, Ribosomal Rna, Spirillum
Document Summary
19. 1 life consists of three domains that share a common ancestor. All organisms: have cell membranes and ribosomes, have a common set of metabolic pathways (glycolysis, replicate dna semi-conservatively, use dna as the genetic material to encode proteins (follow the central dogma) Differences result in domains: bacteria, archaea, eukarya. Prokaryotes are different from eukaryotes because: they do not divide by mitosis, they organize their dna differently, they lack organelles. Although archaea and bacteria are both prokaryotes, archaea is likely more related to. Eukaryotes: eukarya may have been archaea that engulfed a bacterium through endosymbiosis. Gram-positive retains the dye in a thicker coat around the cell membrane. Gram-negative retains less of the dye and shows a very thin layer. The nucleotide sequence of prokaryotes reveals their evolutionary relationships: rrna is especially important for phylogenetic trees because rrna was present in the common ancestor of all life.
