Answer and Explanation:
The Huntington disease is caused by a mutation in the gene that codifies for the Huntingtin protein (Htt). The mutation produces an altered form of the protein leading to the neuron´s death in certain areas of the brain.
The Huntington disease characterizes for being,
- Hereditary, passing from generation to generation. To express the disease, a person must have been born with an altered gene.
- Autosomal, affecting men and women equally, because the mutated gene is located on an autosomal chromosome.
- Dominant, which means that by getting only one copy of the altered gene coming from any of the parents, the receiving person will express the disease. The mutation in the gene dominates over the normal gene copy.
- Expressed by heterozygosis. Most people affected by the disease are heterozygous, with a normal copy and a mutated copy.
There are just a few cases all around the world (3% approximately) in which the disease is expressed with no family history. The progenitors are not affected by the mutation. These cases are very rare and are called <u>"de-novo" mutations.</u> A new mutation is spontaneously produced and it is not inherited from any of the parentals. It consists of an increase in the number of CAG repetitions. In a normal person, the number of CAG repetitions is less than 35. When there are 40 or more repetitions it occurs the disease. But when there are between 35 and 39 repetitions, the penetrance of the disease is incomplete. This is a "gray zone". Those alleles that fall in the gray zone are unstable and might produce the HD. Individuals with these unstable alleles have a tendency to increase the number of repetitions from generation to generation until the number reaches 40 repetitions and the person expresses the disease. This <u>usually occurs in the paternal germinal line</u>, as it is particularly unstable in sperm and probably meiosis greatly affects their instability, causing an increase in the number of CAG repeats.
The zebra's descendence (offsprings) will not be able to produce blood <span>proteins (hypoproteinemia)
It touches the offspring and not the zebra itself because only the sex cells which gives spermatozoids or ovules) are touched.
The main symptom of hypoproteinemia is swelling of the legs, face and other parts of the body due to fluid accumulation loss of muscle mass.</span>
<span>B. Rocks go through many stages during their formation</span><span>
Sedimentary rocks together with the igneous rocks and the metamorphic rocks are the three main types of rocks that existed on earth. It is formed or made accordingly into four major ways. First, it is formed by depositing weathered remains of "clastic sedimentary rocks" or other rocks. Second, is through accumulation and the consolidation of sediments, thirdly is by depositing the results of biogenic activity and lastly it is formed through precipitation from solution. Limestone, shale, chalk clay and others are best examples of sedimentary rocks. </span>
Explanation:
After repeated stimulation by antigen, B cells can make antibodies that bind their antigen with much higher affinity a process called affinity maturation. ... Thus, antigen stimulation greatly increases the antibody arsenal. Antibodies are proteins, and proteins are encoded by genes.
