Topic 12, Chromatin and chromosome structure

Topic 12, Chromatin and chromosome structure - Topic...

Info iconThis preview shows pages 1–15. Sign up to view the full content.

View Full Document Right Arrow Icon
Topic 12—Chromatin and Chromosome structure
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Learning Objectives Be able to define the following terms: histones, chromosome, chromatin, nucleosome, acetylation, antibodies Be able to explain how DNA can be compacted (via histones and other interactions) Be able to explain how modification of histone proteins can lead to changes in chromatin structure and gene expression Be able to describe how the ChIP assay works and how to interpret the results
Background image of page 2
Overview DNA needs to be compact, because the length of total DNA is much too long to fit into a single cell Histone proteins are used to both compact the DNA and to control access of genes in the DNA to transcription (gene expression)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chromatin only forms in eukaryotic, not prokaryotic cells
Background image of page 4
Size of a typical human cell nucleus=5 μ m or 0.000005m (about 2.05m)
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2.05m long, but fits into 0.000005m? 410,000x compacted to fit into a nucleus That is pretty compact!
Background image of page 6
We still don’t fully understand the entire process…. . Packing ratio refers to how compact the DNA is relative to DNA which is not compacted at all
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
DNA exists in different configurations, depending upon the cell cycle What controls the changing conformation of the DNA?
Background image of page 8
Metaphase chromosome As cell divides, DNA must be evenly partitioned between the 2 daughter cells DNA needs to be condensed before cell division. Why? If DNA is not condensed, it may break as it is pulled apart
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Centromere : DNA repeats where spindle fibers attach (for pulling & separation) Telomere : DNA repeats that protect the end of a chromosome
Background image of page 10
Level 1: naked DNA, no compaction
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Level 2: DNA associates with histone octomers
Background image of page 12
Nucleosome = DNA + histone About 1.6-2 twists of DNA per nucleosome (organism-specific)
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
acid sequence of a histone protein
Background image of page 14
Image of page 15
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/04/2011 for the course MMBIO 240 taught by Professor Bridgewater during the Fall '09 term at BYU.

Page1 / 41

Topic 12, Chromatin and chromosome structure - Topic...

This preview shows document pages 1 - 15. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online