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.
A proper habitat and Preferences different specialized niches
The mass (in grams) of NaCl required to prepare the solution is 36.27 g
<h3>What is molarity?</h3>
Molarity is defined as the mole of solute per unit litre of solution. Mathematically, it can be expressed as:
Molarity = mole / Volume
<h3>How to determine the mole of NaCl</h3>
- Volume = 200 mL = 200 / 1000 = 0.2 L
- Molarity = 3.1 M
- Mole of NaCl =?
The mole of NaCl in the solution can be obtained as follow:
Molarity = mole / Volume
Cross multiply
Mole = Molarity x Volume
Mole of NaCl = 3.1 × 0.2
Mole of NaCl = 0.62 mole
<h3>How to determine the mass of NaCl </h3>
We can obtain the mass of NaCl needed to prepare the solution as follow:
- Molar mass of NaCl = 58.5 g/mol
- Mole of NaCl = 0.62 mole
- Mass of NaCl = ?
Mole = mass / molar mass
Cross multiply
Mass = mole × molar mass
Mass of NaCl = 0.62 × 58.5
Mass of NaCl = 36.27 g
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Answer:
There are two different types of leaves – simples leaves and compound leaves. The other types of leaves include acicular, linear, lanceolate, orbicular, elliptical, oblique, centric cordate, etc. They perform the function of photosynthesis and help in the removal of excess water from the aerial parts of the plant. The most obvious aspect to examine is the shape of the leaf. If it is an uninterrupted shape, it is simple. If the shape divides into smaller leaf sets the leaf is compound. Identifying plant leaves that are compound divides them into subsets.
