36 Questions
What type of receptor is responsible for detecting sour taste?
TRP receptor
How many different receptors for bitter taste do humans have?
More than 30
What type of receptor is responsible for detecting sweet and umami tastes?
GPCR receptor
What happens when an acid or other sour-tasting substance binds to the sour receptor?
Depolarization occurs
What is the specific type of receptor responsible for detecting salt taste?
Sodium channel
What is the function of GPCR proteins in the sense of smell?
They are critical for the sense of smell
What is the Japanese term for the savory taste?
Umami
What is the name of the flavor enhancer commonly used in food?
Monosodium glutamate
What is the function of a taste receptor cell?
To detect only one type of taste
What is the location of taste buds on the tongue?
Scattered in several areas of the tongue and mouth
What is the function of papillae on the tongue?
To house taste buds
What is the accuracy of 'taste maps' of the tongue?
Not accurate
What is the main function of the receptor cells in taste buds?
To recognize only one of the five tastes
What is the result of a taste cell having a single receptor type?
It can only detect one of the five tastes
Where are the taste buds located in the mouth?
Scattered in several areas of the tongue and mouth
What is the role of glutamate in food?
It adds a savory or umami taste to food
What was the result of the reprogramming experiment using a cloned bitter taste receptor?
It revealed that an individual taste cell expresses a single receptor type
What is the significance of the discovery of receptor proteins for all five tastes?
It reveals the mechanism of taste detection in mammals
What is the main difference between the receptors for bitter taste and those for sweet and umami taste?
The number of receptors for each taste
What is the common feature of the receptors for sour and umami tastes?
They are both ion channels
What is the result of the binding of an acid or other sour-tasting substance to the sour receptor?
Depolarization of the taste cell
What is the specific type of ion channel involved in the detection of sour taste?
Assembled TRP proteins
What is the relationship between the number of GPCR proteins and the number of receptors for sweet and umami taste?
One pair of GPCR proteins per receptor
What is the role of the GPCR proteins in the detection of bitter taste?
They recognize multiple bitter tastants
What is the function of glutamate in foods?
To impart a savory or umami flavor
What was the outcome of the reprogramming experiment using a cloned bitter taste receptor?
The taste cell expressed a single receptor type
What is the arrangement of taste buds on the tongue?
Associated with nipple-shaped projections called papillae
What is the significance of identifying receptor proteins for all five tastes?
It reveals the molecular basis of taste perception
What is the relationship between taste buds and papillae?
Taste buds are found on the surface of papillae
What is the accuracy of 'taste maps' of the tongue?
They are inaccurate
What is a characteristic of the bitter taste receptors in humans?
Each receptor can detect multiple bitter tastants.
What is the function of the GPCR proteins in taste buds?
They recognize and respond to sweet and umami tastants.
What is the mechanism of the sour taste receptor?
It is a TRP protein that assembles into an ion channel in the plasma membrane.
What is the function of the sour receptor in taste buds?
It assembles into an ion channel in the plasma membrane.
What is the specific type of receptor responsible for detecting salt taste?
Sodium channel
How do the sour receptors respond to acid or other sour-tasting substances?
They trigger a change in the ion channel.
Study Notes
Taste Receptors
- G protein-coupled receptors (GPCRs) are required for sweet, umami, and bitter tastes.
- Humans have one type of sweet receptor and one type of umami receptor, each assembled from a different pair of GPCR proteins.
- There are more than 30 different receptors for bitter taste, each able to recognize multiple bitter tastants.
Sour Taste Receptor
- The receptor for sour tastants belongs to the TRP family and is similar to the capsaicin receptor and other thermoreceptor proteins.
- In taste buds, the TRP proteins of the sour receptor assemble into an ion channel in the plasma membrane of the taste cell.
- Binding of an acid or other sour-tasting substance to the receptor triggers a change in the ion channel, resulting in depolarization and activation of a sensory neuron.
Salt Taste Receptor
- The taste receptor for salt is a sodium channel.
- It specifically detects sodium salts, such as NaCl.
Taste in Mammals
- Humans and other mammals perceive five tastes: sweet, sour, salty, bitter, and umami.
- Umami is elicited by the amino acid glutamate, which is found naturally in meat, aged cheese, and other foods.
- Glutamate is sometimes used as a flavor enhancer in the form of monosodium glutamate (MSG).
Taste Cells and Taste Buds
- Taste cells are modified epithelial cells organized into taste buds.
- Taste buds are scattered in several areas of the tongue and mouth.
- Most taste buds on the tongue are associated with nipple-shaped projections called papillae.
- Any region of the tongue with taste buds can detect any of the five types of taste.
- Researchers have identified the receptor proteins for all five tastes.
Research and Findings
- Scientists used a cloned bitter taste receptor to genetically reprogram gustation in a mouse, revealing that an individual taste cell expresses a single receptor type and detects tastants representing only one of the five tastes.
This quiz explores the five tastes perceived by humans and other mammals: sweet, sour, salty, bitter, and umami. Learn about the role of glutamate in enhancing flavors and the debate among researchers about taste cell receptors.
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