1. Chromosomes & meiosis

2. What makes cells different?
The human body is made up of two major groups of cells:
1. Somatic cells – body cells
(body tissues and organs)
2. Gametes – sex cells
(egg & sperm)
Somatic cells are diploid (2n) and contain two copies of each chromosome.
Gametes are haploid (n) and contain one copy of each chromosome.
What makes cells different?

3. How are chromosomes organized?
Somatic cells have 23 pairs of chromosomes. (46 total)
Each pair is homologous – two chromosomes with the same structure. One copy from each parent.
Pairs are called autosomes.
Pair 23 are the sex chromosomes.
(XX – female XY – male)
Gametes have one set of 23 single
chromosomes.

4. Meiosis is a process where haploid cells are produced.
There are two rounds of division.
Meiosis 1 divides homologous chromosomes.
Meiosis 2 divides sister chromatids.
The end result is four genetically unique haploid cells.
What is meiosis?
ergy

5. Draw on the top of pg. 26