Working with the Vocabulary: In your own words, explain how a person may taste the bitterness of PTC by using the following vocabulary words in your explanation (choose any order): trait, gene, genotype, phenotype, and alleles. Underline each word as you use it in your explanation. In this explanation, you can treat PTC taste sensitivity as a single- gene trait. [As mentioned in the video, it may be more complex than a single-gene trait.]

Tasters” report that the strip tastes very bitter, while “nontasters” may only detect a small amount of bitterness, if at all. The ability to taste PTC is due changes in the TAS2R38 gene that affects the function of bitter taste receptors on the tongue.

The version of the gene that allows tasting of PTC is masked if it is paired with the version of the gene that does not allow tasting.  Traits could come from either parents. A person will only get a bitter taste from PTC if they inherit a copy of the gene for tasting PTC from both of their parents. Some people will have different genotype. so some people may have it Therefore in a family tree , only the grandfather and the youngest daughter can taste PTC.

Explanation:

the answer is: the „power stroke“ step.

muscle contraction can be divided into a few steps:

1. the release of ach (acetylcholine) in the synaptic cleft, binding of ach for its receptor and consequently opening of the ca channels.

2. the release of ca, binding of ca for the troponin

3. troponin shifting the tropomyosin, which was blocking the active site on the actin

4. myosin heads attaching to actin by breaking down atp to adp+ pi

5.   formation of the ‘cross-bridge’ on the active site of the actin filament by myosin head

6. “power stroke” -the cross bridge pulls actin, which slides over the myosin

9.     7. the release of adp completes the cross-bridge movement and atp attaches to myosin, breaking the actin-myosin cross bridge.