A nucleosome muaj 147 lub hauv paus khub DNA uas tau qhwv ib ncig ntawm 8 histones hu ua octomer. Lub nucleosome tuaj yeem muab quav ntxiv los tsim cov chromatin fiber. Chromatin fibers yog coiled thiab condensed los ua chromosomes.
Chromatin ua li cas?
Chromatin yog muaj DNA thiab histones uas tau ntim rau hauv nyias, stringy fibers. Cov chromatin fibers tsis yog condensed tab sis tuaj yeem muaj nyob rau hauv ib daim ntawv cog lus (heterochromatin) lossis tsawg dua daim ntawv (euchromatin). Cov txheej txheem suav nrog DNA replication, transcription, thiab recombination tshwm sim nyob rau hauv euchromatin.
Chromatin tsim li cas thiab nws tsim dab tsi?
Nucleosomes quav los ua ib qho 30-nanometer chromatin fiber, uas tsim cov voj voog nruab nrab ntawm 300 nanometers ntev. 300 nm fibers yog compressed thiab folded los tsim ib tug 250 nm-wide fiber, uas yog nruj nreem coiled rau hauv lub chromatid ntawm ib chromosome.
Vim li cas chromatin tsim?
Chromatin yog cov khoom tsim los ntawm chromosome uas muaj DNA thiab protein. Cov proteins loj hauv chromatin yog cov proteins hu ua histones. Lawv ua raws li ntim khoom rau DNA. Yog vim li cas chromatin tseem ceeb yog nws yog ib qho zoo nkauj ntim ua kom yuam kev kom tau tag nrho DNA hauv ib lub cell.
Puas yog chromatin ua los ntawm DNA?
Chromatin yog qhov nyuaj ntawm DNA thiab cov proteins uas tsim cov chromosomes hauv cov nucleus ntawm eukaryotic hlwb. … Hauv qabmicroscope nyob rau hauv nws daim ntawv txuas ntxiv, chromatin zoo li hlaws dai ntawm ib txoj hlua. Cov hlaws yog hu ua nucleosomes. Txhua nucleosome yog tsim los ntawm DNA qhwv ib ncig ntawm yim proteins hu ua histones.
