1. Some of the “C” words

2. What is a Chromosome?
Structure containing the genetic material (DNA) within a cell
Are always present in a cell, but usually are too thin to be seen

3. Chromosome Structure
DNA exists in the form of CHROMATIN for most of the cell’s life
Long strands of DNA wrapped around protein molecules
When a cell is getting ready to divide, chromatin coils, thickening and shortening to form CHROMOSOMES

4. Chromosome Structure CHROMATID – exact copies of DNA
CENTROMERE – holds sister chromatids together

5. Chromosome Number How many chromosomes are in each of your cells?
Humans = 46
23 from mother’s egg, 23 from father’s sperm
AUTOSOMES – chromosome pairs 1-22
“Non-sex” chromosomes
SEX CHROMOSOMES – pair #23
Determines the sex/gender of individual
XX = female XY = male

6. Karyotypes
A picture showing all chromosomal pairs for an individual