No Nucleus
All members of the kingdom Monera have no nuclei in their cells. All genetic material in moneran cells floats loose in the cytoplasm. In fact, the only parts of the cell that exist in a moneran are the cell wall and the ribosomes. Moneran cell walls are made of peptidoglycan. This is the case for all monerans except for archaebacteria. Monerans also move about using flagella.
Digestion
Monerans digest their food outside of the cell and then absorb the nutrients. Different monerans, however, digest their food in a variety of ways. Some simply generate their own food by making their organic compounds. Others need to feed off of other organic matter, such as decaying material. Some monerans are parasites that feed off of a host and others create a symbiotic relationship with another organism. According to Thinkquest.com, monerans are separated into different classifications by how they feed.
Other Characteristics
Monerans reproduce by both sexual conjugation or asexual binary fission. Circulation is done by diffusion, which is similar to the way they digest. Monerans all breathe differently. Some cannot survive without oxygen while some die if exposed to oxygen. Monerans come in three different shapes: spiral, rod-shaped or spherical. In order to protect themselves, most Monerans are surrounded by a capsule of polysaccharides that keeps them from drying out and acts as protection against other harmful cells.
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.
Answer:
Four cell processes that all living cells need energy for include:
Cell Division
Synthesis
Transport
Breakdown of Nutrients
Let me know if this helps!
