DNA to Chromosomes
DNA to Chromosomes
Eukaryotic cell: Hierarchy of Biological Information
Human body cells each contain about 2 meters of DNA.
• If all the DNA in every cell of a person was stretched out it would reach to the sun and
back about 70 times!
Length of Human DNA
How can 2 meters of DNAfit here?!
Chromatin
• 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
Chromatin
Chromatin
• Chromatin = complex of DNA, proteins, and RNA with nucleosomes as the basic structural & functional unit.
The DNA Nucleosome and
Supercoiling
The answer is:
The DNA nucleosome
DNA actually occurs in units called nucleosomes during interphase.
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
The DNA nucleosome: More images
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!
DNA to Chromosomes Video Animation
Human Chromosome