A: poisons taste bad

2. [2 points] Which of the following is true of gustatory transduction? (circle all that apply)

a. Bitter and sweet substances bind into receptor sites.

b. Sour substances contain H+ ions that block channels in the membrane.

c. Salty substances break up into Na+ ions which flow through the membrane directly into the cell.

d. Transduction occurs when different taste substances cause a change in the flow of ions across the membrane of a taste cell.

A: a, b, c, d (all of them are true)

3. [2 points] Why does orange juice taste gross if you've just brushed your teeth? (25 words or less)

A: because of cross-adaptation. your sweet receptors become desensitized by the sweetness of toothpaste, so when you drink OJ, bitterness is the strongest taste

4. [2 points] Briefly describe how different smells are encoded by the olfactory system. (20 words or less - really!)

A: there are about 1,000 different receptor proteins that are receptive to different odorants

5. [1 point] Suppose you wanted to fake a tone of 80 Hz. Which of the combinations of tones below would be perceived as having a pitch of 80 Hz? (circle all that apply)

a. 10, 20, 40

b. 20, 40, 60

c. 160, 240, 320

d. 160, 320, 640

e. none of the above

A: c (it has to be successive multiples of 80)

6. [1 point] (True or False) The cochlea analyzes incoming sound into its constituent frequency components and translates the components into separate areas along its length.

A: TRUE

7. (1 point) A Fourier spectrum is a plot of

a. bandwidth as a function of amplitude

b. frequency as a function of pitch

c. energy as a function of frequency

d. frequency as a function of bandwidth

e. pitch as a function of loudness

f. loudness as a function of pitch

g. none of the above