1. CHAPTER 8 Chromosomes pp

2. Chromosomes: coiled and compact DNA in nucleus
DNA wrapped tightly around proteins called histones
Chromatids: two halves of a dividing chromosome
Chromatids joined by a centromere

4. Chromosome number: each organism has a specific number of chromosomes
Sex chromosomes: determine sex of the organism (X or Y)
female: XX male: XY
Autosomes: all other chromosomes
All organisms have two copies that are homologous

5. Haploid vs Diploid
Haploid (n): only 1 set of chromosomes (n=23) like egg or sperm cells
Diploid (2n): having 2 sets of chromosomes (2n=46)
morphologically similar: homologous
one set from mom and one set from dad
2 haploid cells (sperm and egg) can combine to make a diploid (zygote)

7. Karyotype: photo of chromosomes
Block cells in cell division and stain the condensed chromosomes with dye
Thinnest bands contain over a million base pairs and hundreds of genes
Bands can be used to identify chromosomes and possible genetic disorders due to the wrong number of chromosomes