Taste Perception Lab and Signaling Mechanisms

What is the correct order of events in a taste receptor’s signaling pathway?

• Transduction, Reception, Response

• Reception, Transduction, Response

• Response, Reception, Transduction

• Transduction, Response, Reception

Which event directly causes neurotransmitter release in taste receptor cells?

• Hyperpolarization of the cell membrane

• Decrease in intracellular Na⁺

• Release of K⁺ through leak channels

• Entry of Ca²⁺ into the cell

Why does Gymnema tea block the sensation of sweetness?

• It permanently destroys sweet receptors

• It fills sweet receptor binding sites and prevents sugar from binding

• It increases firing of bitter receptors

• It activates umami receptors instead

Which taste relies primarily on ion channels rather than G protein pathways?

• Sweet

• Bitter

• Salty

• Umami

mBerry alters taste perception by:

• Blocking calcium channels in sour receptors

• Changing the shape of sweet receptors so acids activate them

• Preventing Na⁺ from entering salty receptors

• Stimulating taste buds to release more neurotransmitter

Which statement best describes taste receptor specificity?

• All receptors can detect all tastants

• Each receptor type binds only certain molecules

• Sour and sweet molecules activate the same receptors

• Blocking one receptor affects all taste pathways equally

Gymnema tea blocks the perception of sweetness. Explain the cellular mechanism that causes this, and describe how this demonstrates the importance of receptor structure in signal transduction.

Sour foods normally activate a specific signal transduction pathway in taste cells. After mBerry, these foods taste sweet instead. Explain how mBerry alters receptor function and how this change affects both the transduction stage and the final neural response.

A student reports that salt tastes the same before and after Gymnema tea. What does this indicate about the specificity of taste receptor proteins and the independence of different signal transduction pathways?

A tastant produces a strong depolarization in a receptor cell. Predict how this will affect neurotransmitter release and the firing rate of the gustatory neuron, and explain why in terms of the transduction pathway.