1. Chromosome Structure Review
Gene – DNA is a large molecule broken down into hereditary units called genes
DNA is organized & packaged into chromosomes
Chromosome – DNA wound or coiled tightly around proteins (histones)

2. Structure – fully condensed, duplicated
A chromosome is made of 2 identical halves called a chromatids.
A centromere holds 2 chromatids together
DNA is packaged as a chromosome only during cell division, after it has been copied.
When a cell is not dividing, its DNA is packaged more loosely as chromatin.

4. Chromosome #’s Review- each species has a different number of chromosomes
Sex Chromosomes – and X or Y chromosome
Autosomes – all remaining chromosomes
Homologous Chromosomes – a pair of similar chromosomes (1 from mom, 1 from dad)

5. Diploid Cells
Are cells having all homologous pairs and 2 sex chromosomes
body cell, or somatic cells
Diploid cell are abbreviated as 2n, where n = # of 1 set of chromosomes.
The chromosomes of diploid cells can be arranged and studied using karyotypes.

7. Haploid Cells
Cells that contain only 1 chromosome from the pair of homologous chromosomes and 1 sex chromosome.
Haploid cells are abbreviated as n.
Haploid cells are gametes.

8. Mitosis in a Plant Cell

9. Mitosis in an Animal Cell