chapter 11 - Chapter 11: Chromosome Structure and...

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1. Packing DNA a. DNA is very long b. Structure i. Primary Structure- Nucleotide sequence ii. Secondary Structure- Alpha Helix iii. Tertiary Structure- Higher Order Folding c. Supercoiling i. Coiled tertiary structure that forms when strain is placed on a DNA helix by over winding or under winding ii. Allows for higher order folding 2. Bacterial Chromosome a. A circle of DNA b. Lacks histone Proteins c. Other proteins compact it d. Nucleoid i. Clump of DNA confined to a region of the cytoplasm e. It gets folded into a series of twisted loops 3. Eukaryotic Chromosome a. Each replicated chromosome contains a single dna molecule b. The amount of DNA “packaging” changes: i. Temporarily during the cell cycle ii. Locally during replication and transcription c. DNA+ Proteins= chromatin d. Histones are the most abundant: i. H1, H2A, H2B, H3, H4 e. Non histone proteins provide structural support and regulate transcription and replication i. Ex: Kinetochore ii. Molecular Motors iii. Proteins attached to telomeres f. DNA Packing i. Histones form octomers ( 2 each of H2A, H2B, H3, H4) 1. Called core porticals ii. The DNA wraps around the octomer ball twice, then goes on to the next one. iii.
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This note was uploaded on 06/28/2011 for the course BY 210 taught by Professor Powell during the Summer '08 term at University of Alabama at Birmingham.

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chapter 11 - Chapter 11: Chromosome Structure and...

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