DNA Content + Packages in Different Organisms

Prokaryotic DNA Content

1 circular chromosome; 2-3 million BP

Eukaryotic DNA Content

multiple linear chromosome

Human Genome Proj.

Genome contains 3.2ish billion BP; lined up to 6 feet

1st level of DNA packaging into chromatin and chromosome

• DNA wrapped around histone octomer (8 proteins) 2 times

  • 55 BP nts. + wrapped around histone octomer 2x

2nd level of DNA packaging into chromatin and chromosome

30 nm-fiber = chromatin → 10 nm fiber coiled into solenoid structure

3rd level of DNA packaging into chromatin and chromosome

during cell replication, chromatin condenses further into chromosomes

Nucleosome

histone octomer w/ DNA wrapped around bead

• + 55 BP naked DNA (linked) between nucleosomes

Cytosine and guanine amount of hydrogen bonds

3

Adenine and thymine amount of hydrogen bonds

2

Karyotype

ordered arrangement of chromosomes from smallest to largest

Haploid #

“n” - number of unique different chromosomes

• only found in GAMETES

Diploid #

“2n” - 2 sets of 23 for a total of 46

Somatic cells

“non sex,” are diploid

• 1 set of 23 chromosomes from mother

  • 1 set of 23 chromosomes from father

Chromosomes

1-22 = autosomes

• in diploid autosomes in 2 copies = Homologous

• same genes @ same location = locus/loci

Human Male

XY

Human Female

XX