Cycle 6: Endosymbiosis and Antibiotics

• Prokaryotes


  Energy production is inefficient
• Organelles


  Specialization of certain organelles increases efficiency
• Eukaryotes


  Specialized organelles allow for more efficient cells
• Modern mitochondria and chloroplast are


  Significantly smaller than the genome sizes of the ancestral organisms that they originate
• Horizontal Gene Transfer (HGT)


  Genes of one genome can be relocated to another genome overtime (gene function does not change, only the location does)
• Why does HGT happen?


  Nuclear genome = boss, more genes = more control, nucleus is much safer than the mitochondria and chloroplast (highly reactive environments)
• Bacteria as a prokaryote


  Fast doubling time, no nucleus but circular chromosomal DNA, plasmids non-chromosomal DNA
• Penicillin Mechanism of Action


  Copies the substrate in the active site, competitive inhibitor (irreversible formation of covalent bond)
• Bacterial Cell Wall (Peptidoglycan)


  Peptide + Sugar (polysaccharide), cross-linking of peptide chains catalyzed by transpeptidase
• Antibiotics


  Attack the processes required for DNA replication and synthesis
• Mitochondria


  Came from prokaryotes, but divide much slower
• Assay for antibiotic resistance

  Deadzone = no bacterial growth (lots of dark grey = large deadzone = no resistance to antibiotics)
• Mutations from DNA(Step 1 of Antibiotics Resistance Development)


  Usually deleterious or neutral, rarely advantageous, mutations are not a response to antibiotics (are random)
• Conjugation (Step 2 of Antibiotics Resistance Development)

  Plasmid replicated and transferred (HGT)
• Intrinsic resistance


  The ability to resist the action of that antibiotic as a result of an inherent structural or functional characteristic