Quiz 7 - PTC Taster Lab

Polymerase Chain Reaction (PCR)

A technique used to amplify a single copy or a few copies of a piece of DNA to generate thousands to millions of copies of a particular DNA sequence.

HaeIII

A restriction enzyme used in the PTC PCR lab that searches the DNA molecule until it finds a GGCC recognition sequence, cuts DNA to produce "blunt ends"

PTC Gene

A taste receptor gene which allows people to taste bitter molecules, abbreviation for phenylthiocarbamide

Chromosome 7

Location of the PTC (TAS2R38) gene

Sodium Benzoate

A chemical found naturally in foods such as cranberries, prawns and dairy products like milk, cheese and yogurt.

Thiourea

A chemical that has a bitter taste similar to that of PTC

TT

The genotype of an individual who is a strong taster for PTC, appears as two fragments during gel electrophoresis (177 bp, 44 bp)

Tt

The genotype of an individual who is a weak taster for PTC, appears as three fragments during gel electrophoresis, (221 bp, 177 bp, 44 pb)

tt

The genotype of an individual who is a non taster for PTC, appears as one fragment during gel electrophoresis (221 bp)

Single Nucleotide Polymorphism

A variation within a DNA sequence occurring when a single nucleotide is changed, found in more than 1% of the population, (SNP or SNiP)

Mutation

A change in a DNA sequence, found in random locations within the genome, that affects genetic information and found in less than 1% of the population

Arthur L. Fox

DuPont chemist who discovered the presence of the PTC gene in 1931

Five Different Tastes

Sweet, salty, sour, bitter, umami

Selective Advantages for Taste

Allows organisms to obtain more calorie or nutrient rich foods, and to avoid compounds that are harmful or toxic in the environment

T1R2 Gene in Felines

The gene that is turned off in cats and made them lose their ability to taste sweet substances

Hummingbirds

The only bird population that favors sweet tasting foods because they have mutated versions of the T1R1 and T1R3 genes

25 Genes

The number of genes for bitter taste receptors in humans, whereas rats have 37 genes and dogs have 16 genes

15%

The approximate percentage of adults that may have a taste disorder

10,000

The approximate number of taste buds humans have a birth

Hypogeusia

Reduced ability to taste (disorder)

Ageusia

Complete loss of taste (disorder)

Dysgeusia

Distortion of the sense of taste leaving a foul, rancid, or metallic taste in the mouth, or a burning mouth

Causes of Taste Disorders

Present a birth, upper respiratory tract infections, head injuries, chemical exposure or medications, head and neck chemotherapy/radiation for cancer treatment

ENT

Another name for an otolaryngologist or ear, nose and throat doctor

Taste Tongue Map

A common misconception that different sections of the tongue are exclusively responsible for different basic tastes

Taste Receptor Cell

A cell within the taste bud that contains a protein receptor projection that can interact with taste stimuli.

35

Number of cycles of PCR for PTC taster lab

221 base pairs

The length of the PTC gene fragment amplified during the PCR portion of the lab