Yuav ua li cas yog ib tug chromatid? Kev Kawm Ntawv chromatids

Yuav ua li cas yog ib tug chromatid? Cell division yog qhov tseem ceeb rau lub neej ntawm ib multicellular kab mob. Nyob rau hauv lub kawg, peb tau tag nrho cov tsim los ntawm ib tug cell, uas twb muab faib dua thiab dua. Thaum lub sij hawm tus txheej txheem no, nrog rau cov nucleus raws li muaj tej yam pom nyob rau hauv eukaryotic hlwb, uas yog hu ua mitosis thiab meiosis. Chromatids - ib daim qauv ntawm cov chromosomes uas tau tsim ua ntej lub nuclear fission.

Variability nyob rau hauv lub hom

Thaum nws los txog rau evolution, caj haiv yog tshwj xeeb yog noteworthy. Nyob rau hauv meiosis (cov txheej txheem ntawm nuclear fission) lub tsim ntawm lub haploid gamete hlwb - phev thiab ovum. Ntau caj haiv tsub kom nyob rau hauv ob lub ntsiab lus qhia. Firstly, lub homologous chromosomes raug muab faib cia rau hauv tus ntxhais lub hlwb, thiaj li muaj ntau ntau yam tau ob peb ua ke ntawm niam thiab txiv chromosomes. Homologous recombination (pauv sequences) yog tus thib ob txoj kev uas yuav ua rau kom lub caj haiv.

Yuav ua li cas yog chromatids: Lus Txhais

Thaum lub sij hawm cell division lub duplicates yog koom nrog txhua lwm yam nyob rau hauv ib thaj av hu ua lub centromere. Thaum kev cob cog rua tus muam chromatids yog cais los ntawm txhua lwm yam nyob rau hauv lub anaphase ntawm mitosis, lawv txhua tus tau txais ib lub npe tshiab - tus ntxhais chromosomes. Yuav ua li cas yog ib tug chromatid hauv ib? Ncav hais lus, nws yog ib tug ntawm 2 nucleoprotein filaments tsim los ntawm ob npaug chromosomes uas tshwm sim thaum lub sij hawm cell division. Lawv yog ib nrab ntawm ob tug zoo tib cov ntawv luam ntawm replicated chromosomes.

Kev Kawm Ntawv chromatids

Chromatin - ib tug DNA uas yog lub qhov txhab nyob ib ncig ntawm cov proteins, yog li txoj kev ib tug kauv fibers. Nws yog los ntawm lawv thiab tsim ib tug chromatid. Ua ntej replication chromosome tshwm raws li ib tug ib leeg-tso tseg chromatids. Tom qab replication, nws yuav paub tag nrho cov X-puab. Txhua tus tib neeg cell muaj ib tug 23 chromosome officers, muaj ib tug tag nrho cov xov tooj ntawm 46 chromosomes.

xaus

Chromatid hu ua tog twg los ntawm lub ob cov ntawv luam ntawm cov DNA molecule ua ke constituting ib tug chromosome uas tau yav tas los replicated, thiab yog kev cob cog rua nyob rau hauv ib thaj av hu ua lub centromere. Qhov no lub npe yog siv raws li ntev raws li cov tib centromeres nyob twj ywm nyob rau hauv kov. Thaum chromosomes raug muab faib thaum lub sij hawm anaphase ntawm meiosis los yog mitosis, lub filamentous chromatids ua cov me nyuam chromosomes. Cias muab, nws halves lub replicated chromosomes.