Chapter 1 Homework a RNA a 1 3 2 does 1 An important assumption of molecular sequence comparisons to generate phylogenies is a Species that share a more recent common ancestor will have fewer differences than species that have been separated for longer periods of time 2 Which is a true statement a The cell wall is constructed differently in all three domains 3 If there are 5 nucleotide sequences between species A and B 12 between species A and C and 14 between species B and C one can conclude a Species A and B shared a common ancestor after they shared a common ancestor with species C 4 Which molecule probably came first 5 What is the most likely sequence of events that may have taken place to generate the first cells 1 Form RNA 2 Assemble membranes 3 Form catalytic molecules 6 Bacteria are able to occupy more habitats than eukaryal cells because they a Have greater metabolic diversity 7 Anoxygenic photosynthesis differs from oxygenic photosynthesis in that a Anoxygenic photosynthesis does not produce oxygen while oxygenic photosynthesis 8 Which of the following is NOT one of Koch s postulates a The microbe must be re isolated from experimentally infected hosts and injected into another host to be sure it is still infectious 9 Pasteur s famous experiment with swan necked flasks showed a Both boiling broth media killed whatever microorganisms may have been present and whatever was responsible for causing broths to turn turbid came from the air 10 An important finding from Edward Jenner s vaccination experiment is a Immunity to one microorganism can be conferred by exposure to a closely related microorganism 11 The key features of living organisms include all of the following except a Transmission of nerve impulses 12 Select the incorrect statement regarding macromolecules found in cells a The repeating subunits of DNA are ribonucleotides whereas in RNA they are deoxyribonucleotides 13 The domains of living organisms include a The eukarya which are organisms containing cells that have a membrane bound nucleus the archaea which are simple single celled organisms that manufacture mRNA and proteins in a manner similar to eukaryotes and the bacteria which are also simple single celled organisms that synthesize mRNA and proteins 14 Why are microbes useful in research a Many microbes can grow rapidly on inexpensive media and be genetically manipulated quite easily they can be cultivated in the lab many of them have metabolic and regulatory pathways that are very similar to those found in more complex organisms e g complex eukaryotes and they can be used for large scale production of chemical compounds and useful macromolecules 15 How did the first membranes form resulting in something resembling a cell a Since lipid bilayers can spontaneously assemble from lipids in an aqueous solution it is possible that they formed around mineral aggregates trapping informational RNA and basic building blocks inside to generate something similar to a cell 16 How did mitochondria arise in eukaryal cells a Mitochondria contain a DNA molecule that encodes a primitive ribosome similar to that of bacteria It is currently believed that mitochondria arose when a bacterial cell was engulfed inside of an archaeal or early eukaryotic cell The bacterial cell provided ATP to the host cell while the host provided protection as well as a steady food supply resulting in an endosymbiotic relationship Endosymbiosis also led to the development of chloroplasts 17 DNA sequencing has affected our understanding of microbes by a Enabling us to more exactly determine the relatedness between organisms improving the tree of life enabling us to determine the processes by which evolution occurs and enabling us to determine why similar bacteria can have very different properties e g why one bacteria causes disease while the other is harmless 18 The endosymbiotic theory explains a The origin of eukaryotes 19 Eukaryotes originated over ago by endosymbiosis a Two billion a DNA a Protista 21 All of the following are domains except 20 PCR takes small amounts of DNA and produces large amounts of 22 Evidence that mitochondria in chloroplasts are derived from bacteria is a The presence of their own DNA the presence of their own protein synthesizing machinery and similar 16s rRNA gene sequences 23 Transcription is a RNA synthesis from a DNA template 24 Joseph Lister is famous for a Recognizing that cleanliness and disinfection greatly reduced the number of casualties in hospitals 25 An important challenge in the global effort to battle infectious diseases in a Access to the vaccines and antibiotics is limited in many parts of the world the development of resistance to common antibiotics and the lack of vaccines against several important diseases