An adventure in sterechemistry

An Adventure in Stereochemistry: Alice in Mirror Image Land

The beautiful spring day made Alice reluctant to go to her study room. She knew, though, she had to study for her first organic chemistry exam her professor was going to give her the next day. As she entered her house, she found her cat eagerly awaiting her arrival. Alice sighed, “I am sorry, kitty. I cannot play with you; I have tostudy for my organic chemistry exam.” Alice settled into her comfortable chair, opened her organic chemistry text and began to read. Alice looked at herself in the mirror opposite to her. She studied mirror images all the time in her organic chemistry class. She wondered how life would be on the other side. She jumped up from her chair, entered through the mirror into the Mirror Image Land (MIL).She was stopped by an old man wearing a worn out jacket. “Who are you?” asked the old man. “I am Alice, from the other side of the mirror. Who are you?” asked Alice. “I am Professor Meso, an organic chemist. May I ask why you are here?” “I have come to explore the Mirror Image Land.” replied Alice. “Oh! I see! Life is quite different here. Would you like some gum?” “Yes, thank you.” replied Alice.As Alice started to chew the gum, she exclaimed, “It tastes like sweet rye bread.” “I can understand. You are not one of us.” said Professor Meso. “What do you mean?” shrieked Alice. “Well, spearmint plant in your world is made up of L-Carvone, which is associated with the smell and taste of spearmint. But in this mirror image land, our spearmint plants are made up of DCarvone. The receptors inyour body can recognize the L form but not the D form.” A confused Alice now became very worried. She knew she could not stay in the mirror image land for too long as she could run into serious problems.

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She asked the professor, “Can I breathe? Drink water?” Professor replied, “Yes, you can do both of those. The air and water molecules are same in both lands.” Alice felt comfortable withthe answer and she asked, “Can I eat something? I am hungry.” Professor Meso replied, “I am afraid that this may not be possible. All the enzymes in your body can recognize only the foods in your own world. They cannot recognize the food in the Mirror Image Land. Enzymes function via the lock and key mechanism. Your enzymes only recognize Lamino acids. Our world has D-amino acids. It would be aterrible misfit. The carbohydrates in your world are different from ours. You would obtain no nutritional value from our foods.” Alice remarked, “What about fats?” Professor replied, “That is something that you may be able to get by. There are some fats that you can eat and some you cannot digest.” A confused Alice was also falling sick. “Professor, I have a terrible headache. Is there a pharmacywhere I can buy something?” “Oh dear, you must be very careful with medications. Some may work while others may be a poison. Choose carefully.” Alice was now very frustrated and angry. She said very loudly,”What about vitamins?” A sympathetic professor replied, “For the same reason, some vitamins are good for you while others are not.” Alice was now very curious to know if anyone else had visited theMirror Image Land before her. Professor Meso shaked his head and replied, “Oh dear! You are not the first one. Let me tell you a sad story. A pregnant lady Sally stopped by. She was a little nauseous. She picked up an anti nausea drug. I heard later that her child had severe limb deformities such as ‘flipper’ arms and legs. This condition was linked to the anti nausea drug that she took in theMirror Image Land.” The professor continued, “Oh and that poor boy! He was sick but did not want to stay in bed. He entered the Mirror Image Land and picked up Robitussin cough syrup. It killed him. Your cough syrup contains a compound that twists to the right; our twists to the left. Apart from the direction of their twisting they are indiscernible. Oh actually, there is one difference. Your cough...