1. Atypical Cell Division

2. Sometimes, body processes can go wrong
Sometimes, body processes can go wrong. One of these processes is cell division.
When something goes wrong with a somatic cell, there are millions of other cells in the same place so it often causes no noticeable effect.

3. When something goes wrong with a reproductive cell, however, it is more trouble.
If that sperm or egg with a problem results in an embryo all of the cells will be affected.

4. Nondisjunction is a failure to separate that can occur between two homologous chromosomes during meiosis.
As a result, one of the daughter cells is missing a chromosome, and the other has an extra chromosome. These cells will not function properly.

5. If the cell with the extra chromosome develops, one of the problems is Down syndrome.
People with Down syndrome have an extra chromosome on pair 21. This usually results in a mental disability, though there are a wide range of possibilities.

6. Klinefelters syndrome is another example of too many chromosomes
Klinefelters syndrome is another example of too many chromosomes. The child inherits two X chromosomes and a Y chromosome.
The child is a male, but has high levels of estrogen. They do not develop sperm and cannot father children.

7. An example of a disorder caused by not enough chromosomes is Turners syndrome.
Turner syndrome occurs when a female baby has only one X chromosome. These females do not mature sexually and are shorter in height.

8. Karyotyping
A karyotype is a picture of the chromosomes from a cell, arranged in homologous or similar pairs.
The chart is organized from the largest pair (#1) to the shortest pair (#22).
Pair #23 are the sex chromosomes. Remember that because a male has mismatched sex chromosomes that will be the only time the two chromosomes don’t look exactly the same.