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Bmsc 220 - Topic 4 pt 2

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tasnimjaisee's version from 2017-09-21 17:01

Section

Question Answer
ChromatinDNA when its complexed with proteins (2x more protein than DNA)
Amount of DNA and number of protein coding genesdoesn't exist with chromosomes - Random
What is the genome size of humans?3B
Nuclesome Unit of chromatin
Histoneshigh portion of basic amuno acids, arginine and lysine - Binds to -ve charge DNA sugar phosphate backbone
EuchromatinDecondensed- transcriptionally active interphase chromatin
Heterochromatincondensed - transcriptionally inactive chromatin - highly repeated DNA sequences
Two types of heterochromatinConstitutive - Facultative
Constitutive heterochromatinDNA that is not transcribed in any cell type (ex. some DNA sequences at centromeres)
Facultative heterochromatinDNA sequences that are not transcribed in the cell being examined but may be transcribed in other cell types
Histone modificationsregulate gene transcription - relaxes the chromatin structure - allows for DNA sequences to be accessible for transcription
What do acetylation of specific lysine groups on the tails of histone proteins, do?neutralize the positive charge of those lysines
Histone acetyltransferases (HAT)Adds acetyl groups
Histone deacetylases (HDAC)remove acetyl groups
centromeric histone H3Assembles kinetichore
Telomeressequences at the ends of eukaryotic chromosomes - Maintains linear stability - Linked to aging (shorter T and reproduction) - Repeats of DNA sequence with cluster of G residue in 1 strand - Maintained by tempmerase
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