Q: A chemical binds to an olfactory receptor, activating a G protein. Which equation best represents the next step in the signal transduction pathway?

$$G_{olf} \rightarrow \text{Adenylate cyclase} \rightarrow \text{cAMP}$$

Question 1

Which ion is primarily responsible for the transduction mechanism of sour taste in taste receptor cells?

Accepted Answer

H$$^{+}$$

Question 2

A patient reports a loss of ability to taste sweet foods but can still taste salty and sour. Which type of molecule is most likely not being detected by their taste receptor cells?

Accepted Answer

Ligands such as sucrose and aspartame

Question 3

Which of the following statements best describes the pattern theory of taste coding?

Accepted Answer

Taste is coded by the pattern of activity across multiple receptor cells.

Question 4

Which taste sensation is most associated with the detection of protein or amino acid-rich foods?

Accepted Answer

Umami

Question 5

A person with damage to their olfactory epithelium may have trouble detecting airborne chemicals. Which cell type is responsible for responding directly to odorants?

Accepted Answer

Receptor cells

Question 6

Which of the following steps occurs FIRST in olfactory signal transduction?

Accepted Answer

Dissolution of the chemical in mucus

Question 7

What is the role of olfactory binding proteins in the process of olfaction?

Accepted Answer

They transport odorants to olfactory receptors.

Question 8

Which of the following best explains why olfactory receptor cells are unique among neurons?

Accepted Answer

They are continuously replaced throughout life.

Question 9

A chemical binds to an olfactory receptor, activating a G protein. Which equation best represents the next step in the signal transduction pathway?

Accepted Answer

$$G_{olf} ightarrow 	ext{Adenylate cyclase} ightarrow 	ext{cAMP}$$

Question 10

Which of the following is TRUE regarding the distribution of taste receptor cells within a taste bud?

Accepted Answer

Different types of receptor cells are located within a taste bud, with some differential distribution.

Question 11

If a mutation caused the loss of function in the gene coding for olfactory binding proteins, which of the following would most likely occur?

Accepted Answer

Odorants would not be efficiently delivered to olfactory receptors, reducing sense of smell.

Question 12

Which of the following ions is involved in the depolarization of olfactory receptor cells after cAMP opens cation channels?

Accepted Answer

Na$$^{+}$$ and Ca$$^{2+}$$

Question 13

A person is unable to distinguish between sweet and umami tastes but can still taste sour and salty. Which type of transduction mechanism is most likely impaired?

Accepted Answer

Ligand binding to taste receptors

Question 14

Which anatomical structure allows the axons of olfactory receptor cells to pass from the nasal cavity to the brain?

Accepted Answer

Cribriform plate

Question 15

Which of the following best describes the specificity of olfactory receptor cells?

Accepted Answer

Each cell is specific for a particular type of odorant-binding protein.

Question 16

If a person has a blocked nasal cavity preventing chemicals from reaching the olfactory epithelium, which sense would be most affected?

Accepted Answer

Sense of smell (olfaction)

Question 17

Which of the following is a correct sequence of events in olfactory signal transduction?

Accepted Answer

Odorant binds receptor $$\rightarrow$$ cAMP produced $$\rightarrow$$ cation channels open $$\rightarrow$$ depolarization

Question 18

Which cell type in the olfactory epithelium is responsible for maintaining the extracellular environment?

Accepted Answer

Sustentacular cells

Question 19

A person is exposed to a new odorant that activates a previously unused olfactory receptor gene. What does this suggest about the genetic coding of olfactory receptors?

Accepted Answer

There are about 1000 genes coding for olfactory receptors, allowing for detection of many odorants.

Study Notes: Sensory Systems – Taste and Olfaction

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