1. The Smells Lab WHY DOES MOLECULAR STRUCTURE MATTER?

2.  Your job will be to determine this by:  Investigating the smells of a variety of substances  Correlating whether or not a substance smells with various molecular properties such as: shape & polarity WHY DO WE SMELL CERTAIN SUBSTANCES AND NOT OTHERS?

3. WHAT TWO PROPERTIES HAVE WE BEEN STUDYING? ARE THERE ANY TRENDS?

4.  The 5 senses involve receptors that receive a signal from an environmental stimulus and communicate with the brain via sensory neurons.  Touch: pressure (mechanical)  Vision: visible EM spectrum  Hear: sound waves  Taste: tastant molecules  Smell: molecules 5 SENSES

5.  Taste cells have projections on their cell membrane called microvilli.  Microvilli have embedded receptors.  Binding receptor changes an internal environment of the taste bud cells; which sends signal to the brain via neuron.  Why do we taste? TASTE: A SIMILAR MODEL

6.  Size and shape of molecule allows it to dock a specific receptor.  Ex. Bitter tasting molecules all have similarities in shape: WHY DO WE TASTE?

7.  What is different?  Why might they taste different for some people? DO ARTIFICIAL SWEETENERS TASTE LIKE THE REAL THING?

8. FURTHER STUDIES: CAN YOU EAT SOMETHING AND GET A BAD TASTE?

9.  Molecules can taste different when temperature is changed. Especially molecules that have a high heat of solution.  This is why some foods have a different taste when heated or cooled! DO OTHER CHARACTERISTICS IMPACT TASTE?

10.  Introduction:  Research the olfactory sense…what might you need to explain similar to how I introduced taste?  What characteristics might relate to smell…what would the reader need to know about these characteristics.  Hypothesis: Answer your question based on research!  Methods:  Start with the compounds provided; identify whether or not they smell and research 4 properties of the molecules (shape, polarity and 2 others!!!)  Data Analysis:  Organize table(s) to identify compounds and analyze trends!  Conclusions:  Use data to support what properties allow the sense of smell!  Discuss sources of error or limitations to your experiment.  Identify the connections to the chemical theme and the next steps…what more could be learned about the sense of smell and molecular structure? HOW IS SMELL SIMILAR TO TASTE?