Biochemistry of Olfaction

<p>α-gustducin is involved in the transduction of sweet, bitter, and umami taste signals. (B)</p> Signup and view all the answers

<p>T1R2 (B)</p> Signup and view all the answers

<p>It is a component of a multimeric channel complex that is involved in calcium influx. (C)</p> Signup and view all the answers

<p>Spicy (A)</p> Signup and view all the answers

<p>Smell amplifies our sense of taste, making food more enjoyable. (B)</p> Signup and view all the answers

<p>Sodium ions (D)</p> Signup and view all the answers

<p>Bitter and sour (D)</p> Signup and view all the answers

<p>They are involved in the production of diacylglycerol, but the specific mechanism is not yet fully understood. (B)</p> Signup and view all the answers

<p>It relies on a smaller number of receptor types. (D)</p> Signup and view all the answers

<p>Umami (C)</p> Signup and view all the answers

<p>Impaired ability to detect pheromones. (A)</p> Signup and view all the answers

<p>Taste and smell are independent senses. (B)</p> Signup and view all the answers

<p>Ca2+-dependent desensitization of the CNG channel (A)</p> Signup and view all the answers

<p>It increases the kinetics of Ca2+/calmodulin-mediated desensitization of the CNG channel (B)</p> Signup and view all the answers

<p>cGMP (D)</p> Signup and view all the answers

<p>It plays a major role in the detection of semiochemicals (C)</p> Signup and view all the answers

<p>By actively transporting Cl- ions into the cell (D)</p> Signup and view all the answers

<p>It activates the CNG channel (B)</p> Signup and view all the answers

<p>By activating multiple downstream signaling molecules (B)</p> Signup and view all the answers

<p>The vomeronasal transduction pathway is less well characterized than the olfactory transduction pathway (B)</p> Signup and view all the answers

<p>Increased permeability of the cell membrane to Ca2+ (D)</p> Signup and view all the answers

<p>It inhibits the CNG channel, leading to a rapid decrease in the response (D)</p> Signup and view all the answers

<p>It has a low basal activity and a high catalytic rate, leading to rapid, odor-specific signaling. (A)</p> Signup and view all the answers

<p>cAMP activates the olfactory cyclic nucleotide-gated ion channel (CNG), leading to calcium influx. (A)</p> Signup and view all the answers

<p>It is responsible for the depolarization of the cell membrane through the influx of Na+ and Ca2+ ions. (B)</p> Signup and view all the answers

<p>Direct binding to the olfactory receptor (OR), initiating the signaling cascade. (A)</p> Signup and view all the answers

<p>It enhances the depolarization of the cell membrane by increasing the outward flow of Cl- ions. (C)</p> Signup and view all the answers

<p>PLC cleaves phosphatidylinositol 4,5-bisphosphate (PIP2) into IP3 and DAG, triggering alternative signaling pathways. (D)</p> Signup and view all the answers

<p>CNGA2, CNGA4, and CNGB1b (B)</p> Signup and view all the answers

<p>ORs bind odorant molecules, triggering the activation of the G protein G olf. (C)</p> Signup and view all the answers

<p>OR genes are clustered in the genome, suggesting a process of tandem duplications during evolution. (B)</p> Signup and view all the answers

<p>It creates a driving force for Cl- ions to move outward, further depolarizing the cell upon odorant stimulation. (C)</p> Signup and view all the answers

<p>It couples odorant receptors to adenylyl cyclase (ACIII), leading to the production of cAMP. (A)</p> Signup and view all the answers

<p>Both channels contribute to the overall depolarization of the cell, amplifying the signal. (B)</p> Signup and view all the answers

<p>It is selective for anions, allowing for the influx of Cl- ions. (B)</p> Signup and view all the answers

<p>G olf is a G protein that converts GDP to GTP, activating adenylyl cyclase. (D)</p> Signup and view all the answers

<p>It activates the CNG channel, leading to the influx of Na+ and Ca2+ ions and cell depolarization. (D)</p> Signup and view all the answers

A protein that binds odorants in olfactory neurons, initiating signal transduction.

An olfaction-specific G protein that aids in signal transduction for smell.

A second messenger in olfactory signal transduction that leads to ion channel activation.

A channel activated by calcium influx that contributes to depolarization of olfactory neurons.

A membrane phospholipid that gets cleaved to produce second messengers IP3 and DAG.

A second messenger that opens cation channels during olfactory signal transduction.

A sequence of molecular events triggered by odorant binding that leads to sensory perception.

Receptors that recognize sweet and umami stimuli through G protein-coupled mechanisms.

T1R1 is found on the anterior tongue; T1R2 is on the posterior tongue.

T1R1/T1R3 heteromers respond to umami stimuli like L-amino acids; enhanced by 5'-ribonucleotides.

Receptor family responsible for detecting bitter tastes, using a separate signaling cascade.

A G protein involved in mediating sweet, bitter, and umami taste responses in taste receptor cells.

A G protein that couples odorant receptors in olfactory sensory neurons (OSNs).

An isoform of adenylyl cyclase enriched in olfactory cilia, essential for cAMP production.

A second messenger crucial for odor signaling in olfactory sensory neurons.

Loss of sense of smell, which can result from ACIII gene deletion.

Cyclic nucleotide-gated channels that facilitate cation influx in response to cAMP and cGMP.

An obligatory subunit for CNG channel function in olfactory neurons.

Cations that enter the cell during the odor response, contributing to depolarization.

A Ca2+-activated Cl– conductance channel involved in further depolarizing olfactory sensory neurons.

High chloride ion concentration in olfactory neurons that contributes to depolarization.

Neurons that express receptors related to pheromone detection.

Classes of vomeronasal receptors that detect pheromones.

A channel subunit associated with vomeronasal sensory neurons.

The ability to distinguish different flavors through taste.

Bitter, sweet, sour, salty, and umami are the main tastes we perceive.

Molecules that are sensed by the taste receptors.

The taste associated with glutamate and aspartate.

The hydrogen ion is perceived as sour.

Sodium ions are perceived as salty.

Smell enhances the perception of taste.

Olfactory neurons maintain a high Cl- concentration to supply their own driving force.

This pathway involves several amplification steps between odorant binding and signal generation.

The termination of a response despite the continued presence of an agonist.

An intermediate Ca2+-binding protein that mediates Ca2+-dependent desensitization of ion channels.

A subunit that increases the kinetics of Ca2+/calmodulin-mediated desensitization of the native channel.

An enzyme involved in the hydrolysis of cAMP, implicated in odor adaptation.

Ca2+/calmodulin kinase II, involved in phosphorylation linked to longer-lasting adaptation.

An accessory chemosensing system involved in detecting semiochemicals, vestigial in humans.

The process by which chemosensory neurons convert chemical signals into electrical signals.