Lab 9: Human Genetics & Human Perception

The variants PAV, AVI, refer to specific amino acid differences at three positions.  These variants are best referred to as 

 

pleiotypes

diplotypes

teletypes

haplotypes

haplotypes

In figure 1 of the Bufe et al.  paper, they measured cytosolic levels of ____ to assess TAS2R38 responses to PTC, because downstream signaling from the receptor opens channels on the ______.

calcium

endoplasmic reticulum

According to the EC50 data in Figure 1 of the Bufe et al. (2005) paper, the receptor variant that shows a half-maximal response at the highest concentration of PTC is:

 

PVV

PVI

AAI

AAV

PVI

Pick the correct chronological order for the different procedures in this lab:

A.  Dissolve Miraculin on tongue

B.  Discuss the Bufe et al. paper while you wait 1 hour

C.  Expose your tongue to the Gymnema tea

D. Complete entering all your taste test ranks into the class data sheet

E. Taste PTC paper

 

E, D, A, C, B

C, E, A, B, D

E, A, B, C, D

C, A, D, C, B

 E, A, B, C, D

In the Bufe et al. paper, researchers used 3 different assays to study gene expression. To determine the amount of transcript present in a tissue, they used: 

qPCR

 RT-PCR

 In-situ hybridization

qPCR

After having Miraculin, lemon will taste mostly ["sweet", "salty", "sour"]  and sugar will taste ["less sweet than normal", "more sweet than normal", "about the same sweetness as normal"]  .

sweet

less sweet than normal

The image below shows four compounds that humans perceive as bitter. Which chemical would most likely activate TAS2R38? Hint: This is discussed in the conclusion section of the Bufe paper.

B

What happens when a bitter molecule binds its GPCR (G-protein coupled receptor)?

 

The GPCR activates a kinase enzyme that phosphorylates Ca2+ channels, closing them

The GPCR opens, allowing the bitter molecule inside the taste cell

 

The GPCR activates a Ca2+ channel in the plasma membrane, causing Ca2+ to exit the taste cell

 

The G-protein dissociates which leads to the activation of the PLC-beta enzyme, which results in the production of IP3

The G-protein dissociates which leads to the activation of the PLC-beta enzyme, which results in the production of IP3