Bio 124 Lab Report 1

Bio 124 Lab Report 1 - Introduction The ability to taste,...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Introduction The ability to taste, or not to taste phenylthiocarbamide (PTC) is expressed by a single gene that codes for a taste receptor on the tongue. The first acknowledgement of this gene was by Arthur Fox in the 1930s, the actual PTC gene, TAS2R38, was discovered in 2003. There are two common alleles of the PTC gene. Two of the common forms are the tasting allele, and the non- tasting allele. Each allele codes for a bitter taste receptor protein with a slightly different shape. The shape of the receptor protein determines how strongly it can bind to PTC ( Taste, 2009) . Everyone has two copies of every gene hence; combinations of the bitter taste gene variations determine whether someone finds PTC intensely bitter, somewhat bitter, or without taste at all. The ability to taste PTC associates strongly with the ability to taste other bitter substances that occur naturally such as toxins ( Taste, 2009) . This ability to discern bitter tastes has evolved as a mechanism to prevent early humans from eating poisonous plants. PTC sensitivity is an example of a simple Mendelian trait with dominant inheritance. Although sometimes tasters vary greatly in their sensitivity to PTC. The PTC gene has about 85% of the total influence over whether someone is a taster or a non-taster, however there are many other things that can alter a person’s PTC tasting ability ( Taste, 2009) . If one tests for PTC tasting ability under different conditions, the results may vary in their test. If one has a dry mouth it may make it more difficult to taste the PTC. If he or she had ate or drank before sampling the PTC paper also has an effect on their tasting ability. An individual's sensitivity may transform over time. Some testers also find that they can taste PTC on some days, but not on others ( Taste, 2009) . The ability to taste PTC shows a dominant pattern of inheritance. If one does not taste anything the he or she will be homozygous recessive (tt). If one is able to taste a strong bitter flavor he or she will be homozygous dominant (TT). The third outcome of this experiment could
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
BIO 124 Section 65 Lab Report 1 Group 1 be that one is able to taste a mild bitter flavor and can be heterozygous (Tt) . The goal of this study is to determine the individual PTC alleles within the group and the entire class. This way we have a ratio between a small group of 4 and an entire class of 30. The ratios analyzed in this lab help on understand that the PTC gene is a dominant trait as well. Previous scientific information regarding protein coding and receptor binding was used in the understanding of how the PTC gene works. As mentioned before the allele codes for a bitter taste receptor protein with a slightly different shape and the shape of that receptor protein determines how strongly it can bind to the PTC.
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 12

Bio 124 Lab Report 1 - Introduction The ability to taste,...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online