It allows cells and antigen presenting
cells to present a large range of antigens (in the range if millions) to T cells so there is an appropriate
immune response against the invading pathogen
or cancer. This is possible without changing or having many types of MHC
complexes.
Okay, first of all, I don't know what "do we live in" means. I am guessing you're talking about the <u>United States</u>.
We live in the Prevailing Westerlies, which blow in the middle latitudes. Most of North America fits into this belt.
<span>F- allele for freckles
f- </span><span>allele without freckles
1) The man is heterozygote and has freckles, its indicating that the allele for freckles is dominant.
A cross between him and a woman who is also </span><span>heterozygote: Ff x Ff
it would result in the following probabilities:
- 1/4 - homozygote with freckles: FF
- 2/4 - </span><span>heterozygote with freckles: Ff
- 1/4- </span><span>homozygote without freckles:ff
Their son would have a probability of 75% of being born with freckles.
2) The cross resulted in this probabilities:
</span><span><span>- 1/4 - homozygote with freckles: FF
- 2/4 - </span><span>heterozygote with freckles: Ff
- 1/4- </span><span>homozygote without freckles:ff
So, the chance of being born heterozygote for this gene is 2/4, which is the same as half (50%).
</span></span>
The false answer is B because to be exact, the two copies of a gene carried by an organism (such as a Y and a y allele) are located at the same spot on the two chromosomes of a homologous pair. Homologous chromosomes are similar but non-identical, and an organism gets one member of the pair from each of its two parents.
