DNA to Chromosomes

Human body cells each

contain about 2 meters of

DNA.

• If all the DNA in a person was stretched out it

would reach to the sun and back more than

• 300 times!

How can

2 meters of DNA

fit here?!

The DNA Nucleosome

The answer is:

The DNA nucleosome

Candy model of DNA nucleosomes

Eukaryotic cell

The DNA nucleosome

Basic unit of DNA packaging in eukaryotes, consisting of a segment of DNA wound in sequence around histone protein cores.

• Histone proteins = small positively charged proteins that compact DNA into the space of the eukaryotic nucleus

Chromatin

• Chromatin = complex of DNA, proteins, and RNA with nucleosomes as the basic structural & functional unit.

• In eukaryotic cells, DNA is found in the form of chromatin during Interphase (living, functional phase)

• Euchromatin = loosely packed, “active” DNA segments

• Heterochromatin = tightly packed, inactive regions of DNA

• Non-histone proteins = other proteins in nucleus that are not associated with nucleosomes

Chromatin

Prokaryotic DNA organization

DNA to Chromosomes (Eukaryotic Cells)

"Chromatin Structures" by Original uploader was Richard Wheeler at en.wikipedia Later version(s) were uploaded by Seans Potato Business at en.wikipedia. - Transferred from en.wikipedia; Transfer was stated to be made by

User:sevela.p.. Licensed under CC BY-SA 3.0 via Wikimedia Commons -http://commons.wikimedia.org/wiki/File:Chromatin_Structures.png#mediaviewer/File:Chromatin_Structures.png

Chromosomes form when cells are preparing to reproduce!

Chromosomes are passed from one cell to the next!

Human Chromosome