Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is...
-
Upload
melissa-walters -
Category
Documents
-
view
224 -
download
0
Transcript of Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is...
![Page 1: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/1.jpg)
![Page 2: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/2.jpg)
Chromatin packing in eukaryotic cells
Prokaryotic• Smaller genomes • DNA is in a nucleoid region
and is circular.• Prokaryotic cells may have a
separate circular DNA called a plasmid.
Eukaryotic• Larger genomes 6 billion
base pairs (bp) • Genomes are linear• More biochemical editing is
needed. Remember INTRONS and EXONS
![Page 3: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/3.jpg)
Chromatin packing in Eukaryotic cells
• Histones- small proteins usually 100 amino acids in length with positive charges that bind to the negatively charged DNA double helix.
• Nucleosome- is the ENTIRE beadlike unit of DNA packing including histones and DNA.
![Page 4: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/4.jpg)
This model depicts a cross section or end view.
![Page 5: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/5.jpg)
The need to turn transcription on and off.
• All genes all cells.• What are the four basic cell types in
eukaryotes?
![Page 6: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/6.jpg)
SUMMARY THUS FAR
• DNA is coiled around histones.• Tightly coiled DNA is inaccessible to gene reading
machinery.• Methyl groups (-CH 4) molecules bind to the
histone tails and block access to genes and inhibit transcription. This may not be bad. Genes need to be turned off.
• Acetyl (Acetylation) molecules bind to histones and loosen chromatin structure that permits transcription.
![Page 7: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/7.jpg)
IMPLICATIONS
• Epigenetic inheritance- inheritance of traits not directly involving nucleotide sequences.
• Say again?• Molecular mechanism of heritability may not
be limited to DNA sequence differences.
![Page 8: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/8.jpg)
Identical twins in which one acquires a genetic disease and one does not.
![Page 9: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/9.jpg)
• Identical twins are derive form an identical zygote that splits at the two cell state.– Monozygotic twins (MZ) identical– Dizygotic twins (DZ) fraternal
![Page 10: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/10.jpg)
![Page 11: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/11.jpg)
Paradigm shift??????????
![Page 12: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/12.jpg)
• A change in basic assumptions or paradigms within the ruling theory of science. IT IS A REVOLUTION! ?????
![Page 13: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/13.jpg)
Thomas Kuhn: “The Structure of Scientific Revolution”
• A scientific revolution occurs, according to Kuhn, when scientists encounter anomalies that cannot be explained by the universally accepted paradigm within which scientific progress has thereto been made.
• 1962
![Page 14: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/14.jpg)
Barbara McClintock and trasnsposons or transposable genetic elements
![Page 15: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/15.jpg)
• Expression of genes can be tied to other factors besides nucleotide sequences.
• Randy Jirtle Rober Waterland of Duke University
![Page 16: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/16.jpg)
![Page 17: Chromatin packing in eukaryotic cells Prokaryotic Smaller genomes DNA is in a nucleoid region and is circular. Prokaryotic cells may have a separate.](https://reader035.fdocuments.us/reader035/viewer/2022062222/5697bfdd1a28abf838cb15ed/html5/thumbnails/17.jpg)
• Diets supplemented with methyl donors such as choline, folic acid, and B-12) decreased the incidence of offspring with yellow coat color which results in REDUCING the risk of developing obesity, diabetes and cancer.
• Jirtle and Waterland, 2003 nature paper