Nucleotides 1 Flashcards
How does H1 stabilize the chromatin fibers
by binding to both nucleosome and linker dna
negative and positive charge of dna and histone resp reason
negative - phosphates {DNA}
positive - lysine and arginine {histones}
mitochondrial dna
circular
doesn’t utilize histones
histones in octamer
H2A H2B H3 H4
Heterochromatin
Darker
Sterically inaccessible
highly condensed
increased methylation
decreased acetylation
Barr bodies visible on periphery
Methylation
changing expression without changing sequence
functions of methylation
aging
carcinogenesis
genomic imprinting
transposable element repression
X chromosome inactivation {lyonization}
Repression of gene transcription
Methylation with gene promoter {CPG islands}
Disease of dysregulated DNA methylation
Fragile X syndrome
X is fragile cause its being expressed a lot
Histone methylation
Mostly repression
depends on location
Methylation of lysine and arginine residues
Histone Acetlyation
Removes positive charge of histone and increases transcription
Disease of acetylation
thyroid hormone synth is altered by acetylation of receptor
Disease of deacetylation
Altered gene expression of Huntington disease
Nucleoside
base plus deoxyribose
Nucleotide
nucleoside plus phosphate
energy source of nucleotide
5’ end bearing triphosphate
Deamination of cytosine
Uracil
Deamination of adenine
Hypoxanthine
Deamination of Guanine
Xanthine
Deamination of 5’methylcytosine
Thymine
Uracil to thymine
Methylation
Amino acids for purine synthesis
Glycine
Aspartate
Guanine {GAG}
_____ are thin filamentous proteins that form the nuclear lamina and create a dense protein web within the nucleus
Lamin Proteins
Chromatin is usually made up of (number)____ chromosomes in humans.
46
