Tuesday January 11, 2011
Pre-Class Homework
1. In my experience, is this map correct?
Yes, I have felt that his map is correct. It seems that sweeter things are much easier to taste with the tip of my tongue and salty things seem to kind of take over my whole tongue. Also, sour and bitter tastes always seem to give me a funny feeling near the back of my throat which would attest to these tastes being placed near the back of the tongue.
2. Observations of eating with my nose plugged:
I tested this out at my breakfast meal. When I plugged my nose it took away nearly all the flavor from my food. I could almost taste the slightest hint of a sweet or salty taste, but the main interesting part of the taste was gone. It was as if I was eating extremely bland food that needed sugar and salt. It was really hard to differentiate between the different foods, because I could really only go off of texture. It really took all the enjoyment out of the eating experience!
3. More than Meets the Mouth:
a. 5 Tastes: sweet, sour, bitter, salty, umami
The one’s where the jury is still out: fatty and calcium
b. This idea of “the wisdom of the body” may lead us to eat things with calories, because those food items taste good to us. Things that are poisonous taste bitter and rancid; we do not like the taste of them. Our bodies are naturally designed to defend us against things that are harmful. Perhaps by getting a bitter taste from poisonous items is a natural defense system put together by our bodies. Since those things don’t taste good to us we avoid them and thus only want to eat things that are going to sustain and nourish our bodies.
c. This paper talks significantly about genetic variations in taste perception. This could explain why people have an array of different responses to the taste of broccoli. The paper reveals that there has been extensive research on this topic and results have not totally been concluded, but there is strong evidence to support genetic influence in taste responses. For example, some people are genetically unable to taste the compound PTC which is in many nutritious vegetables such as broccoli. So, President Bush could be a person that is able to taste this bitter compound and thus cannot stand the taste of broccoli. However, Mrs. Bush likes broccoli. So, she may have the mutation in her gene that does not allow her to taste the bitter PTC, so she still enjoys the taste of broccoli.
4. Which two systems are the most alike and why?
The two systems that are most alike are that of vision and the olfaction system. This is because they both have a molecule that binds to many different receptors. Also, in order to get a result (either smell or vision) there is a culmination of signals being sent from multiple receptors. In other words, the signals sent are multi-faceted and from many different receptors that must be working together to get the correct signal.
5. Describe an analogy that you could use to explain olfaction to someone outside of this class.
a. My analogy will describe the combinatorial mechanism of olfaction. The trick is that odorants can bind to more than one receptor, but the difference is that some bind more strongly than others. Thus, the smell we interpret is a culmination of signals from many receptors.
b. An analogy is to think of the receptors as keys on a piano. The odorants are the fingers pressing the keys. The fingers can press any key they want to make a sound. So, no matter which key you press there will be sound, but depending on how hard you press and how many the sound will change. Thus each time you add or subtract a key it changes the chord and the sound interpreted. In the same way, when odorants bind or do not bind to different receptors it changes the smell slightly. Also, if one key in a chord is altered, the chord can sound similar but not exactly the same. In the same way, odorants can stimulate many of the same receptors creating a similar smell but not an identical one.
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