(a)++Chromosomes

=** Chromosomes **= Chromosomes are numerous threadlike linear strands that carry genes that determine the characteristics of a person. DNA is a part of the components of the chromosomes, it covers proteins in the chromosome cells; DNA is the information and chromosomes are its carrier.

media type="youtube" key="lUESmHDrN40" height="315" width="560" Karyotype is used to describe the shape and appearance of chromosome in the nucleus of a eukaryote cell (Karyotype). Eukaryote cells are cells with complex structure inside membrane; the eukaryote cells are different from the prokaryotic cells inside membranes because they have nucleus, which contained information. Inside the nucleus are chromosomes with this information. Karyotype is picture of a person chromosome. In the picture, the chromosomes are isolated and divided in pair. This can only be view under the microscope. The karyotype describe the chromosomes in living species and what they look like, length, banding pattern and position of centromere which is a region of DNA found in the middle of chromosomes. By looking at this scientist can also check if the set of chromosomes in that species is enough or not. For human, the karyotype test is often used to check chromosomes abnormality, this test is often perform with white blood cell. It’s often used to test many diseases such as Down syndrome, the disease which is caused by having an extra number 21 chromosome.These chromosomes are arranged by shape and size from largest to smallest. This shows how many chromosomes the person has, his/her characteristics, and most importantly it makes it easy for experts to spot chromosomal alterations that might result to genetic disorders. **Characteristics of the Karyotypes:** There are 6 different characteristics that can be observed in karyotypes. The 6 differences are:
 * (**[])
 * What is a karyotype?**
 * 1) The sizes of the chromosomes
 * 2) The position of the centromeres
 * 3) The sizes of the chromosomes which can cause unequal lenghts
 * 4) The number of chromosomes
 * 5) The number and position of satellites
 * 6) The degree and distribution of the heterochromatic regions

A normal person usually has 46 chromosomes, however sometimes a person might have too many or too few, missing pieces or mixed up pieces:
 * Using a karyotype to predict genetic disorders:**

**__example:__** one popular disorder is down syndrome, which is caused because there is another copy of gene 21, down syndrome is pretty common, 1 out of every 800-1000 kids have it, it create physical abnormities.

The cell then divides into two cells, with 23 chromosomes in each: The two cells then split into halves forming 4 egg or sperm cells. There are 23 chromosomes in each cell: The sperm and the egg cell then fuse together creating a zygote with 48 chromosomes:
 * How do cells have 46 chromosomes (23 pairs)? ** Through meiosis (a cell division process) 23 chromosomes are copied forming 46 duplicated chromosomes.

During an abnormal meiosis scene, the cell also starts off with 46 chromosomes. As before the chromosomes are duplicated and the cell is split creating 2 cells with 23 chromosomes in each. However, when the cell divides, each cell does not have even number of chromosomes: The two cells then divide creating 4 new egg or sperm cells, the cells still do not have equal numbers of chromosomes: During fertilization, two cells with different number of chromosomes will fuse together, creating a zygote with chromosomes that might have more copies or less: People who are born with abnormal numbers of chromosomes usually have genetic disorders.
 * How do cells end up with too many or too few chromosomes? **


 * How do cells have missing pieces? **

It is called a deletion when genetic material is missing from the chromosome: this is called deletion. Large deletions result to the loss of many genes, resulting to genetic disorders.

Terminal deletion: when the tip of the chromosome is lost Interstitial deletion: a piece from the middle of the chromosome is broken off and the pieces are rejoined. It is called translocation when there is a chromosome rearrangement. This can result to genetic disorders. Reciprocal translocation: when an even swap of parts of the chromosome is made between two chromosomes Robertsonian translocation: when the chromosomes’ arms join together and the two arms are lost.
 * Works Cited:**

"Chromosome." //Wikipedia//. N.p., n.d. Web. 19 Oct. 2011. [].

"Down Syndrome." //LabCorp: LabCorp Home Page//. Web. 26 Oct. 2011. [].

"Eukaryote." //Wikipedia, the Free Encyclopedia//. Web. 26 Oct. 2011. []. "Karyotype." //Wikipedia//. N.p., n.d. Web. 19 Oct. 2011. [].

"Karyotype - What Is a Karyotype." //Down Syndrome - Information on Causes, Care and Resources for Down Syndrome Families//. Web. 26 Oct. 2011. .

"Make a Karyotype." //Learn.Genetics//. N.p., n.d. Web. 19 Oct. 2011. .

"Using Karyotypes to Predict Genetic Order." //Learn.Genetics//. N.p., n.d. Web. 19 Oct. 2011. [predictdisorder/].