Qhov sib txawv tseem ceeb ntawm bivalent thiab synaptonemal complex yog tias bivalent yog kev koom tes ntawm txiv neej thiab poj niam homologous chromosomes thaum lub synaptonemal complex yog tripartite protein qauv uas tsim ntawm ob homologous chromosomes.
Meiosis yog txheej txheem ntawm cell faib ua raws li gamete hlwb. Thaum lub sij hawm meiosis, tus lej chromosome raug txo los ntawm ib nrab kom tswj tau tus lej chromosome thaum muaj kev sib deev. Cov txiv neej thiab poj niam chromosomes cais thiab muab faib mus rau hauv ib tiam zuj zus. Muaj ob theem tseem ceeb ntawm meiosis: lawv yog meiosis I thiab meiosis II. Zoo ib yam li mitosis, meiosis kuj mus txog theem ntawm prophase, metaphase, anaphase thiab telophase.
Cov chromosomes tau txais los ntawm ob lub gamete hlwb: poj niam ovum thiab txiv neej phev. Yog li ntawd, thaum lub sij hawm meiosis txheej txheem, cov homologous chromosomes hla dhau. Thaum lub sij hawm meiotic prophase, bivalents yog tsim, thiab cov noob caj noob ces sib xyaw ntawm cov ntsiab lus hu ua chiasma. Bivalent los yog tetrad yog ib lub koom haum ntawm homologous chromosomes tsim thaum lub sij hawm prophase I ntawm meiosis. Kev tsim cov synaptonemal complex yog thawj kauj ruam ntawm cov txheej txheem ntawm kev tsim ib tug bivalent complex. Nws yog cov qauv protein uas tsim ntawm ob homologous chromosomes thaum lub sij hawm meiosis.
Bivalent yog dab tsi?
Bivalent yog tsim thaum lub sij hawm meiosis txheej txheem ntawm homologous chromosomes. Ob pawg chromosomes los ntawm txiv neej thiab poj niam gamete koom nrog hauv meiosis. Cov bivalent yog tsim los ua ib qho kev sib koom ntawm txiv neej thiab poj niam homologous chromosomes. Lub bivalent tseem hu ua tetrad. Nyob rau hauv ib txwm cell faib cov xwm txheej, txhua lub bivalent muaj tsawg kawg yog ib qho hla hla lub npe hu ua chiasma. Tus naj npawb ntawm chiasma nyob rau hauv bivalent muab ib lub tswv yim hais txog tus ntoo khaub lig tshaj efficiency ntawm DNA thaum lub sij hawm meiosis. Kev tsim ntawm bivalent hauv meiosis yog qhov tseem ceeb vim nws tso cai rau kev sib cais ntawm chromosomes thaum lub sij hawm meiosis.
Daim duab 01: Bivalent
Kev tsim ntawm bivalent yog txheej txheem nyuaj thiab suav nrog cov kauj ruam hauv qab no:
- Tsim cov synaptonemal complex uas muaj ob homologous chromosomes.
- Kev sib koom ntawm ob homologous chromosomes, uas tshwm sim ntawm leptotene thiab pachytene theem ntawm prophase I ntawm meiosis.
- DNA yog pauv ntawm qee cov ntsiab lus hu ua chiasma.
- Ib qho kev sib txuas ntawm lub cev yog tsim nyob rau hauv theem diplotene ntawm prophase I ntawm meiosis.
- Thaum kawg ntawm lub sijhawm diplotene, ib qho bivalent tsim.
Kev tsim ntawm bivalents yuav xyuas kom meej tias cov caj ces muaj nyob rau hauv sib xyaw ntawm gamete hlwb. Thaum tsim cov bivalents, qhov nro yog tsim, thiab txhua chromatid raug rub mus rau qhov sib txawv. Qhov no yuav cia cov bivalents npaj nyob rau hauv nruab nrab ntawm lub cell.
Dab tsi yog Synaptonemal Complex?
Synaptonemal complex yog cov qauv protein tsim ntawm ob homologous chromosomes. Thiab, cov qauv no pab txhawb homologous chromosome pairing, synapsis thiab recombination. Muaj ob qho tib si nyob rau sab nraud thiab ib qho tseem ceeb hauv lub synaptonemal complex. Yog li ntawd, nws yog ib tug tripartite qauv uas qhia ib tug yam ntxwv ntaiv-zoo li lub koom haum. Peb cov khoom ntawm synaptonemal complex yog tsim los ntawm SC protein-1 (SYCP1), SC protein-2 (SYCP2), thiab SC protein-3 (SYCP3).
Daim duab 02: Synaptonemal Complex
Synaptonemal complex txuas ob homologous chromosomes raws lawv qhov ntev los ntawm cov txheej txheem hu ua synapsis, uas txhawb kev sib txuas ntawm homologous chromosomes. Ntxiv mus, cov synaptonemal complex yog koom nrog hauv qhov tseeb chromosome cais thaum lub sij hawm anaphase I ntawm meiosis.
Dab tsi zoo sib xws ntawm Bivalent thiab Synaptonemal Complex?
- Bivalent thiab synaptonemal complex yog ob lub qauv tsim thaum lub sij hawm meiosis cell division.
- Synaptonemal complex formation yog thawj kauj ruam ntawm kev tsim cov bivalent.
- Ob leeg yog tsim thaum lub sijhawm prophase I ntawm meiosis.
- Lawv yog cov qauv tshwj xeeb nuclear.
- Lawv txhawb genetic recombination.
- Ntxiv mus, lawv tso cai kom raug chromosome cais thaum lub sij hawm anaphase I.
Qhov txawv ntawm Bivalent thiab Synaptonemal Complex yog dab tsi?
Bivalent yog ib lub koom haum tsim los ntawm txiv neej thiab poj niam homologous chromosome khub. Ntawm qhov tod tes, lub synaptonemal complex yog meiosis tshwj xeeb proteinaceous tripartite qauv. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm bivalent thiab synaptonemal complex. Structureally, bivalent yog tsim los ntawm ob homologous chromosomes thaum lub synaptonemal complex yog cov qauv protein uas muaj peb lub ntsiab.
Ntxiv mus, bivalents pab txhawb kev sib txuas ntawm caj ces ntawm homologous chromosomes thaum lub synaptonemal complex txuas homologous chromosomes raws lawv qhov ntev. Yog li, qhov no yog qhov sib txawv ntawm qhov sib txawv ntawm bivalent thiab synaptonemal complex.
Summary – Bivalent vs Synaptonemal Complex
Bivalent yog ib lub koom haum tsim los ntawm ib khub chromosome homologous thaum lub sij hawm prophase ntawm meiosis. Meanwhile, lub synaptonemal complex yog ib tug tripartite protein qauv tsim ntawm ob homologous khub thaum prophase ntawm meiosis. Yog li, bivalent yog ib khub chromosome thaum synaptonemal complex yog cov qauv proteinaceous. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm bivalent thiab synaptonemal complex. Ob lub qauv txhawb nqa caj ces rov ua dua ntawm homologous chromosomes.
