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R and S of Fischer Projections quiz

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  • What is the shortcut for determining R and S configurations in Fischer projections?
    Identify the location of the lowest priority group (4); if it's vertical, use the drawn sequence, if horizontal, flip the configuration.
  • How do you determine the lowest priority group in a Fischer projection?
    The lowest priority group is always labeled as '4' in the sequence of priorities.
  • What should you do if the lowest priority group (4) is vertical in a Fischer projection?
    The chirality is determined directly from the sequence 1 to 3 as it appears.
  • What should you do if the lowest priority group (4) is horizontal in a Fischer projection?
    The chirality is the opposite of what it appears; you must flip the configuration.
  • Why is this shortcut method beneficial for large Fischer projections?
    It allows for quick determination of R and S configurations without converting to bond-line structures.
  • Do you need to swap groups when using this shortcut for Fischer projections?
    No, you never swap groups; you only flip the chirality if group 4 is horizontal.
  • What is the first step in using the shortcut for R and S determination in Fischer projections?
    Identify whether the lowest priority group (4) is vertical or horizontal.
  • How do you assign R or S if the sequence 1 to 3 goes clockwise and group 4 is vertical?
    Assign the configuration as it appears; clockwise means R.
  • How do you assign R or S if the sequence 1 to 3 goes counterclockwise and group 4 is vertical?
    Assign the configuration as it appears; counterclockwise means S.
  • What happens to the configuration if group 4 is horizontal and the sequence 1 to 3 is clockwise?
    You flip the configuration; clockwise would become S instead of R.
  • What happens to the configuration if group 4 is horizontal and the sequence 1 to 3 is counterclockwise?
    You flip the configuration; counterclockwise would become R instead of S.
  • Is converting Fischer projections to bond-line structures necessary with this shortcut?
    No, the shortcut eliminates the need to convert to bond-line structures.
  • What is the main advantage of this shortcut for students?
    It simplifies and speeds up the process of determining absolute configurations.
  • What should you do after determining the location of group 4 in a Fischer projection?
    Draw the sequence from 1 to 3 and assign R or S based on the shortcut rules.
  • What is the call to action for students after learning this shortcut?
    Practice determining R and S configurations using this method on given Fischer projections.