•Every living thing is made up of one or
more cells.
•Each cell is produced by an already
existing cell.
•New cells are formed by cell division, so
that there are 2 cells where there was
once only 1 cell.
There are 2 types of cell division:
1. Mitosis
2. Meiosis
Mitosis
How a body cell divides its
nucleus.
Requires 1 nuclear division
Results in 2 cells with identical
nucleii.
New cells are haploid (N).
Clones of parent cell are
created.
4 Steps
Prophase
Metaphase
Anaphase
Telophase
Meiosis
How a sex cell divides its
nucleus. Only occurs in sperm
and egg cells.
Requires 2 nuclear divisions
WHY?
To reduce the # of
chromosomes to half the #
found in other cells.
Results in 4 cells with identical
nucleii.
New cells are diploid (2N).
WHY?
So new individuals can be
created.
8 Steps
Prophase I
Metaphase I
Anaphase I
Telophase I
Prophase II
Metaphase II
Anaphase II
Telophase II
•After the nucleus divides, the cytoplasm
(cellular jelly) divides and the cells splits.