Lecture 4 Part 2

8 views2 pages
25 Mar 2012
School
Department
Course
Professor
Lecture 5 Jan. 23/12
Genomes and Chromosomes (P2)
Chromosomal packaging
Chromosomes chromatin nucleosomes
Nucleosomes circular histone protein + strings of wrapped DNA
Histones rich in lysine and arginine, +ve charge attracts –ve DNA
Special H1 histone organizes nucleosomes into tighter configuration
H1 histones changes the shape of the chromatin strand into a spiral
Chromatin packing
DNA wraps around histones
H1 histones contorts shape
Condensons (proteins) grab onto loops and condense chromatin further
Heterochromatin
Final product of highly condensed chromatin
Needed around centromeres to keep structural stability
Used in to suppress gene expressions
Condensed DNA is difficult to unravel for gene expression
Ex. Found in an X chromosome in females to control gene dosages, X inactivation
High lysine residues on histones (becomes methylated)
Large +ve attraction to DNA –ve charge
Euchromatin
Non-condensed chromatin
Used when gene expression is needed
Ex. Interphase, transcription
Higher acetylate groups, reduces charges of lysines
Smaller +ve attraction to DNA, DNA can spread out more
Orientation of gene expression
Unlock document

This preview shows half of the first page of the document.
Unlock all 2 pages and 3 million more documents.

Already have an account? Log in

Get OneClass Notes+

Unlimited access to class notes and textbook notes.

YearlyBest Value
75% OFF
$8 USD/m
Monthly
$30 USD/m
You will be charged $96 USD upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.