Midterm 2-7 Flashcards
(15 cards)
What is chromatin remodeling
Creating a DNA protein complex, when DNA is tightly bound to histone proteins. This protects DNA but interferes with transcription. When the histone is moved to allow transcription, this is chromatin remodeling
Where do eukaryotes express gene regulation
Within gene expression pathway: chromatin remodeling, transcription initiation, RNA processing, mRNA stability, translation, and post translation, modification of proteins
What is RNA processing
This modifies eukaryotic gene expression where non coding introns are spliced out of primary RNA transcript and a cap structure is added and a tail
What is alternative splicing
When the exons of a gene are all spliced together in different ways to allow different proteins to be created
What is mRNA stability
When the time that the mRNA are available for translation is modified
What is chromatins basic structure
Chromatin is the molecular complex formed between DNA and proteins in the cell nucleus. Proteins in this complex are called histones and are positively charged due to the high density of lysin and arginine amino acids in chromatin structure. DNA is negatively charged due to phosphate residues in the phosphodyester backbone; therefore, the DNA histone complex forms spontaneously
What are histones/nucleosomes
Histone are this disk shaped object that DNA wraps around, and the complex is called a nucleosome
What is an h1histone
It is not part of the structure but it is associated with the disk shape complex but it is associated with the linker between DNA and the nucleosomes
What is the structure of organizational DNA
Histone association, formation of nucleosomes, nucleosome packing into the 30nm fibers, and looping of the 30nm fiber on a protein scaffold structure
What must happen for a gene to be activated
Activation of a gene must somehow be associated with histone removal
What is DNA methylation
Cystine nitrogenous mases can be covalent lay modified via the addition of a methyl group. This enhances DNA condensation which contributes to inactivating the gene. Inhibiting this process will increase the gene expression
How are histones modified
There is methylation, and regulation of how histones are bound to DNA, this includes (methylation, acetylation, phosphorylation, and adding short peptide chains)
What is HATS and HDACs
Histone acetyl transfer adds negatively charged acetyl groups diminishing histone affinity to DNA while histone deacetylases remove an acetyl group causing the affinity to increase
What is the histone code hypothesis
Combinations of histones modification comprise a regulatory code, influencing gene expression
What does the chromatin remodeling complex do
It’s an ATP consuming enzyme that modifies DNA association with histones. As it slides along the DNA, it can push off histones
