Atypical Cell Division

1
Atypical Cell Division
2

• 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. 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
  dont look exactly the same.