Chirality And Stereoisomers - Dr. Neufeldt

11 Questions | Total Attempts: 755

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Chirality And Stereoisomers - Dr. Neufeldt - Quiz

Welcome to BACON AT UCLA. You have recently been learning about chirality and stereoisomers. In this tutorial, you'll see how these topics connect to artificial sweeteners, medicines, the origins of life, and more! The estimated time needed to complete this tutorial is: 20-30 minutes. Note: The tutorial includes short pre-BACON and post-BACON quizzes. Only your grades on the post-BACON quiz will be recorded. There are also questions embedded throughout the tutorial, on which you will not be graded. YOU MUST LOG IN AND COMPLETE THE TUTORIAL TO RECEIVE CREDIT. Your password is your nine-digit UID (e. G. 001234567)If you are having login issues please email: [email protected] /* */ WARNING…ONCE YOU


Questions and Answers
  • 1. 
    Page 1 of 16Here is a quick refresher for stereochemistry:
  • 2. 
    Page 2 of 16 Here is a quick refresher of enantiomers and diastereomers:
  • 3. 
    Page 3 of 16           Although enantiomers have the same physical properties (e.g.. melting point, boiling point, density, and solubility), they will usually interact differently with other chiral molecules. A common example of this involves the taste and smell receptors in the tongue and nose, respectively.          Two famous examples involve the compounds limonene and carvone. The (–) enantiomer of limonene is recognized as an lemon smell, while the (+) enantiomer is recognized as a orange smell. Also, while (–)-carvone has a spearmint smell, (+)-carvone has a dill or caraway smell. 
  • 4. 
    Page 4 of 16 - SOLUTIONS Assign the absolute configuration in (–)-limonene:a. Rb. SExplanation: The correct answer is B (S configuration) – the explanation is shown below.
  • 5. 
    Page 5 of 16           Another interesting example involves the artificial sweetener Equal and its key ingredient aspartame. Aspartame was first discovered in the 1960s and is now a common ingredient in consumer products, such as candy and soft drinks. Did you know that only one enantiomer of aspartame is used as a sweetener? The (­–)-enantiomer of aspartame is sweet, but the (+)-enantiomer of aspartame is bitter. The difference in taste comes from the two enantiomers interacting differently with our chiral taste receptors. 
  • 6. 
    Pre-BACON Quiz1. Which of the following compounds smells like lemons and is the enantiomer of a compound that smells like oranges?
    • A. 
    • B. 
    • C. 
    • D. 
  • 7. 
    Pre-BACON Quiz2. Which of the following correctly describes the enantiomer of “meth”, the drug frequently seen in the hit TV show “Breaking Bad”?
    • A. 

      It is another drug that is just as dangerous as “meth”.

    • B. 

      It is one of the ingredients used in the artificial sweetener Equal.

    • C. 

      It provides evidence of extraterrestrial life.

    • D. 

      It is used in an over-the-counter medicine to help alleviate nasal congestion.

  • 8. 
    Pre-BACON Quiz3. In the 1950’s the ‘wonder drug’ thalidomide was prescribed to pregnant women for the treatment of morning sickness, but was halted because ___________________________________
    • A. 

      The (S) enantiomer of the drug caused birth defects.

    • B. 

      The (R) enantiomer of the drug caused brain damage.

    • C. 

      The US government redirected their attention to space exploration.

    • D. 

      Both enantiomers of the drug caused birth defects.

  • 9. 
    Pre-BACON Quiz4. What hypothesis has come about, at least in part, because of the discovery of chiral amino acids in the Murchison meteorite, which landed in Australia in 1969?
    • A. 

      The universe is most likely expanding

    • B. 

      Natural amino acids are D-amino acids

    • C. 

      Homochirality originated on Earth

    • D. 

      The origins of homochirality might be extraterrestrial

  • 10. 
    BACON at UCLA – Chirality and Stereoisomers Page 4 of 16 Assign the absolute configuration in (–)-limonene:
    • A. 

      R

    • B. 

      S

  • 11. 
    BACON at UCLA – Chirality and Stereoisomers Page 6 of 16 (–)-Aspartame can be made from L-aspartic acid and L-phenylalanine methyl ester. Identify the absolute configuration of the two chiral centers. 
    • A. 

      Blue = R; Red = S

    • B. 

      Blue = R; Red = R

    • C. 

      Blue = S; Red = S

    • D. 

      Blue = S; Red = R

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