Kingdoms & Domains

• What is an autotroph?

  An organism that can produce its own food through photosynthesis or chemosynthesis from inorganic sources.
• Autotrophs can be either a Photoautotroph or a Chemoautotroph
• What is a Photoautotroph?

  An organism that can make organic compounds using energy derived from the sun
• What is a Chemoautotroph?

  An organism that can make organic compounds using energy derived from the oxidation of chemicals.
• What is a Heterotroph?

  An organism that obtains its energy by consuming other organisms.
• Hetertrophs can be consumers, detritivores, or saprotrophs
• What is a Consumer?

  An organism that ingests organic matter which is living or recently killed (e.g. herbivores, carnivores, scavengers)
• What is a Detritivore?

  An organism which ingests non-living organic matter (e.g. earthworms, woodlice)
• What is a Saprotroph?

  An organism which feeds on non-living organic matter by secreting digestive enzymes and absorbing the products (e.g. bacteria and fungi)
• What can be used to classify organisms?

  Biological molecules like DNA, RNA and Cytochrome C (a protein used in respiration)
• How is Cytochrome c used to find relations between organisms?

  Look at the sequence of amino acids that code for the protein. The greater the difference in the sequence of amino acids for a particular protein, the greater the evolutionary distance between the organisms.
• How is DNA mtDNA and RNA used to find relations between organisms?

  Mutations cause changes in DNA. The more similar the base sequence in a part of DNA, the more closely related the individuals.
• What did Woese find out about Eukayota and Archaea?

  They both have: similar enzymes (RNA polymerase) for synthesising RNA, similar mechanisms for DNA replication and synthesising RNA, production of some proteins that bind to their DNA.
• How did Woese introduce the three domain system?

  By studying differences between organisms at a molecular level and introducing Archaea.
• What did Woese realise about bacteria?

  Bacteria have a different cell membrane structure, flagella with a different internal structure, different enzymes for synthesising RNA, no proteins bound to their genetic material, different mechanisms for DNA replication and for synthesising RNA.
• Which cell component appears in organisms of all three domains that Woese suggested?

  Ribosomes
• What are some defining features of all members of the domain Eukarya?

  nucleus, DNA with histones, linear DNA, membrane bound organelles, 80s ribosomes
• Suggest two ways in which the scientific community are likely to have validated Woese's research

  scientific conferences/meetings, peer review/publication in reputable scientific journal/approving the work for publication, replication of work by others to see if the same results are obtained, look for more supporting evidence