Organization of DNA

Levels of organisation of DNA explains how 2 meters long DNA is compacted into chromatin. Useful self-assessment questions are given in the slides. If you want to know the answer, you can ask in comments.

1. Organisation of DNA Dr. Karthikeyan Pethusamy

2. Chromatin vs chromosome vs chromatid

3. Karyotyping

4. Karyotyping, under light microscope is commonly done by a) R Banding b) Q Banding c) G Banding d) C Banding 

5. Y-chromosome is Telocentric Metacentric Submetacentric Acrocentric

6. Karyotyping of fetus is usually done from all, EXCEPT? A. Chorionic villus sampling B. Cordocentesis C. Amniocentesis D. Fetal skin

7. Level of structural organization of DNA Level Description stabilising forces 1 ° Sequence of nucleotides in 5 ′ → 3 ′ direction Phosphodiester bond 2 ° Double helix ( B - DNA, A - DNA, and Z - DNA ) Hydrogen bond, Stacking of bases ( Hydrophobic interaction ) 3 ° Supercoiling of DNA   DNA-protein interactions 4 ° Chromatin DNA - protein interactions

8. Nucleosome

9. Composition of Histone proteins

10. Packaging of DNA

11. Supercoiling

12. Most Cellular DNA Is Underwound

13. Amino terminal tail

14. Role of histone post-translational modifications

15. Chromatin Remodelling

16. Chromatin Remodelling

17. Chromatin Remodelling

18. Euchromatin Vs Heterochromatin   Euchromatin Heterochromatin On G - Banding Lightly stained Darkly stained Transcriptionally Active Inactive Evolutionary significance Found both in prokaryotes and eukaryotes only found in eukaryotes Epigenetic change associated Histone acetylation Histone deacetylation Sensitivity to DNAse digestion Sensitive Resistant

19. DNAse I hypersensitivity

20. DNA footprinting

21. Chromatin Immuno Precipitation

22. Methods to detect DNA-protein interaction Electrophoretic mobility shift assay DNase footprinting assay Chromatin immunoprecipitation South-western blotting Yeast One-hybrid System (Y1H) Bacterial one-hybrid system (B1H) X-ray crystallography