Olee otú nuclear fission? fission Types

Ọ bụla cell amalite ya ndụ mgbe iche na nne na nna, na-agwụ elu ịbụ, na-enye ohere na-egosi na nwa ha nwaanyị mkpụrụ ndụ. Nature nyere ihe karịrị otu ụzọ nke nkerisi isi, dabere na ha mebere atumatu.

Ụzọ nke cell nkewa

Nkerisi isi na-adabere na ndị cell ụdị :

- ọnụọgụ abụọ fission (hụrụ na prokaryotes).

- amitosis (kpọmkwem nkewa).

- Mitosis (nkịtị na eukaryotes).

- Meiosis (maka nkerisi izizi mkpụrụ ndụ).

fission ụdị na-ekpebisi ike site na ọdịdị na-agbanwe agbanwe na Ọdịdị nke ahụ cell na ọrụ ya rụrụ na macroorganism ma ọ bụ site n'onwe ya.

ọnụọgụ abụọ fission

Ọtụtụ mgbe a na ụdị na-achọta na prokaryotic mkpụrụ ndụ. Ọ mejupụtara na ibawanye okirikiri DNA molekul. Ọnụọgụ abụọ fission nke ntọala a na otú a na-akpọ n'ihi na nke nne cell e nwere abụọ dokwara sized nwaanyị.

Mgbe mkpụrụ ndụ ihe nketa okwu (DNA ma ọ bụ RNA molekul) a kwadebeere ya, i.e. ya okpukpu abụọ, si cell mgbidi amalite na-etolite na transverse nkebi, nke na-eji nwayọọ nwayọọ tapered na cytoplasm ekewa abụọ dị hà akụkụ.

The abụọ n'ikewa usoro akpọ budding ma ọ bụ mkpumkpu ọnụọgụ abụọ fission. Na nke a, na cell mgbidi apụta protrusion òkè, nke a na-eji nwayọọ nwayọọ na-eto eto. Mgbe "akụrụ" na size nke nne cell ga-hà, ha na-iche. A òkè nke cell mgbidi na-synthesized ọzọ.

amitosis

Nke a nkewa nke ntọala yiri ndị ahụ dị n'elu, na ihe dị iche na ọ dịghị ibawanye nke mkpụrụ ndụ ihe nketa na ihe onwunwe. Nke a na usoro e mbụ kọwara Remak bayoloji. Nke a na onu aputa ihe n'akparamagwa pathologically gbanwere sel (ajọ mgbanwe), na bụ a n'ahụ norm maka imeju anụ ahụ, cartilage na cornea.

The usoro a na-akpọ nuclear fission amitosis n'ihi na cell retains ya ọrụ, na anaghị ida ha dị ka n'oge mitosis. Nke a na-akọwa na ọrịa ntutu ịdapụsị Njirimara ndị a na-cell nkewa usoro. Ke adianade do, kpọmkwem nkewa isi na-aga na-enweghị spindle, otú ahụ nwa mkpụrụ ndụ chromatin a na-ekesa uniformly. Na ndị na-esonụ, ndị dị otú ahụ na mkpụrụ ndụ nwere ike iji na-mitotic okirikiri. Mgbe ụfọdụ, dị ka a n'ihi nke amitosis kpụrụ multinucleated mkpụrụ ndụ.

mitosis

Nke a bụ anọ nuclear fission. Ọtụtụ mgbe hụrụ na eukaryotic mkpụrụ ndụ. Isi ihe dị iche nke usoro a dabeere n'eziokwu na nwa na nne nwa mkpụrụ ndụ na-ebu otu nọmba nke chromosomes. Site na nke a na-ahụ na-akwado site na chọrọ ọnụ ọgụgụ nke mkpụrụ ndụ, nakwa dị ka o kwere omume imu na ibu Filiks. The mbụ mitosis na anụmanụ cell kọwara Flemming.

The usoro nke nkerisi ntọala na nke a bụ iche na na interphase na mitosis. Interphase - a ala nke mkpụrụ ndụ zuru ike n'etiti nkewa. Ọ nwere ike ịmata ihe dị iche ọtụtụ n'ụzọ:

1. presynthetic oge - cell na-etolite, ọ accumulates na-edozi na carbohydrates, na-arụsi ọrụ synthesized ATP (adenosine triphosphate).

2. Sịntetik oge - mkpụrụ ndụ ihe nketa na ihe onwunwe na-okpukpu abụọ.

3. postsynthetic oge - na cellular ọcha na-okpukpu abụọ, e nwere ndi na-edozi na-eme ka n'ikewa spindle.

The n'ụzọ nke mitosis

Nkewa nke ntọala nke eukaryotic mkpụrụ ndụ - a usoro nke dị mkpa maka guzobere ihe ọzọ organelles - centrosomes. Ọ na-emi odude nso ntọala, na isi ọrụ bụ na-etolite ọhụrụ organelles - spindle. Nke a Ọdịdị na-enyere aka evenly kesaa chromosomes n'etiti nwa mkpụrụ ndụ.

E nwere ihe anọ n'ụzọ nke mitosis:

1. Prophase: chromatin na ntọala condenses na chromatids, nke na-abịaru nso centromeres na-aga na abụọ na-etolite chromosomes. Nucleoli igbari, achụsakwa ka okporo osisi nke cell centrioles. Kpụrụ nkewa spindle.

2. Metaphase: na chromosomes mere ndokwa na a akara-agafe center nke cell na-etolite na metaphase efere.

3. Anaphase: chromatids diverge si cell center kwupụta okporo osisi, na mgbe ahụ kewara abụọ centromere. Nke a na ije kwere omume n'ihi na nke nkewa spindle, na eri nke nke na-ebelata na agbatị chromosomes dị iche iche ntụziaka.

4. Telophase: kpụrụ nwa nuclei. Chromatids ọzọ ghọọ chromatin, ntọala na-kpụrụ, na ya - nke nucleoli. Agwụ niile nkewa nke cytoplasm na cell mgbidi guzobere.

endomitosis

The na-abawanye na mkpụrụ ndụ ihe nketa na ihe onwunwe, nke adịghị egboro nkewa nke ntọala, a na-akpọ endomitosis. Ọ dị n'ime mkpụrụ ndụ nke osisi na ụmụ anụmanụ. Na nke a na e nweghị mbibi nke ndị na cytoplasm na ntọala akpụkpọ ahụ, ma na-aghọ chromatin n'ime chromosomes, wee dispiralized.

Usoro a na-enye ohere iji nweta polyploid ntọala ebe DNA ọdịnaya ụba. Dị otú ahụ ógbè akpụ mkpụrụ ndụ dị na ụmị ọkpụkpụ. Ke adianade do, e nwere otu, mgbe DNA molekul na-okpukpu abụọ, ọnụ ọgụgụ nke ndị chromosomes anọgide n'otu. Ha na-mara dị ka polythene, na ha nwere ike dị na ụmụ ahụhụ na mkpụrụ ndụ.

pụtara mitosis

Mitotic nkewa nke ntọala - bụ ụzọ ịnọgide na-enwe a mgbe nile na-set of chromosomes. Nwa mkpụrụ ndụ nwere otu set nke mkpụrụ ndụ ihe nketa dị ka a nne na nna na niile nke àgwà pụta ụwa ya. Mitosis a chọrọ maka:

- na mmepe nke multicellular ntule (si anọ na nke izizi mkpụrụ ndụ);

- Ndahie nke ala cell n'ígwé na a top na nnọchi sel ọbara (erythrocytes, leukocytes, platelet);

- idozi mebiri emebi anụ ahụ (na ụfọdụ ụmụ anụmanụ ikike nke imu-ọzọ na bụ a mkpa maka nlanarị, dị ka staafishi na ngwere);

- asexual mmeputakwa nke osisi na ụfọdụ ụmụ anụmanụ (invertebrates).

meiosis

nkerisi izizi mkpụrụ ndụ nuclei usoro iche dịtụ si somatic. Dị ka a N'ihi ya, o nwetara na mkpụrụ ndụ ndị na-enwe ọkara mkpụrụ ndụ ihe nketa ọmụma karịa ha ụzọ. Nke a dị mkpa iji nọgide na-enwe a mgbe nile ọnụ ọgụgụ nke chromosomes ọ bụla cell nke ahu.

Meiosis emee ná nkebi abụọ:

- Mbelata ogbo;

- equational ogbo.

Proper n'oge usoro bụ omume naanị na mkpụrụ ndụ na ọbụna ọnụ ọgụgụ nke chromosomes (diploid, tetraploid, na geksaproidnym t. D.). N'ezie, ọ na-anọgide na o kwere omume ruo meiosis na mkpụrụ ndụ na iberibe set of chromosomes, ma mgbe ahụ ụmụ nwere ike ịbụ viable.

Nke a usoro ana achi achi Vol na interspecific alụmdi na nwunye. Ebe ọ bụ na izizi mkpụrụ ndụ dị iche tent nke chromosomes, ọ sikwuoro ha anọ na na ọdịdị viable na tụụrụ ụmụ.

The akpa nkewa nke meiosis

adọ akuko aha ndị na mitosis: prophase, metaphase, anaphase, telophase. Ma e nwere ụfọdụ dị ịrịba ama dị iche iche.

1. Prophase: abụọ set of chromosomes na-eme ka a na usoro nke mgbanwe, na-agafe ise nkebi (leptotena, zygotes, Paquita, diplotene, diakinesis). E nwere ihe niile a na ekele na conjugation na ịgafe-ihe karịrị.

Conjugation - a convergence nke homologous chromosomes. Na leptotene therebetween etolite mkpa filaments wee sonyere ha zygotene chromosome ụzọ abụọ na n'ihi nwetara site na Ọdịdị nke anọ chromatids.

Crossover - usoro nke cross-ngalaba nke mgbanwe n'etiti nwanne chromatids ma ọ bụ homologous chromosomes. Nke a pụtara na pachytene ogbo. Kpụrụ gaferịtara ibe (chiasm) chromosomes. Na ụmụ mmadụ, ndị a mgbanwe nwere ike n'etiti iri atọ na ise na iri isii na isii. The N'ihi nke a usoro bụ mkpụrụ ndụ ihe nketa heterogeneity nke dapụtara ihe onwunwe, ma ọ bụ mgbanwe gametes.

Mgbe na-abịa a ogbo diplotene anọ chromatids okụre na-ebibi ma na nwanne chromosomes vzaimoottalkivayutsya. Diakinesis enwezu mgbanwe site prophase ka metaphase.

2. Metaphase: chromosomes n'ahịrị nso ụwa nke cell.

3. Anaphase: chromosomes, ka esịnede abụọ chromatids diverge ka okporo osisi nke cell.

4. Telophase: nkerisi spindle na-ebibi, n'ihi na guzobere abụọ mkpụrụ ndụ na a haploid set of chromosomes enwe ugboro abụọ ego nke DNA.

The abụọ meiotic nkewa

Usoro a na-akpọ "mitosis, meiosis." Na oge n'etiti abụọ n'ụzọ DNA mbiputegharị adịghị ime, na nke abụọ cell abatakwa prophase nke otu set of chromosomes, nke ọ nọgidere mgbe 1 telophase.

1. Prophase: chromosomes ebikọta gafee nkewa cell center (ya remnants dị iche okporo osisi nke cell), na n'ọbọ collapses ntọala kpụrụ nkewa spindle ewekarị perpendicular na spindle nke akpa nkewa.

2. Metaphase: chromosomes na-emi odude ke ụwa, a kpụrụ metaphase efere.

3. Anaphase: chromosomes na-ekewa n'ime chromatids na radiate niile ntụziaka.

4. Telophase: na nwa mkpụrụ ndụ kpụrụ isi chromatids dispiralized n'ime chromatin.

Ná ngwụsị nke abụọ na-adọ nke a otu nne na nna cell, anyị nwere anọ ndị enyemaka na a ọkara set of chromosomes. Ọ bụrụ na meiosis-ewe ebe na njikọ na izizi akara (ya bụ, guzobe nke mmekọahụ mkpụrụ ndụ), nkewa na-sharply mkpumkpu, na a kpụrụ site na otu cell na a haploid set of chromosomes na atọ Mbelata nwa ehi, ọ bụghị ndị na-ebu mkpa mkpụrụ ndụ ihe nketa na ozi. Ha dị mkpa iji hụ na na egg na spam nọgidere nanị ọkara nke mkpụrụ ndụ ihe nketa na ihe onwunwe nke ndị nne na nna cell. Ọzọkwa, ụdị nuclear nkewa na-enye onye ahụ nke ọhụrụ n'ịgwa nke mkpụrụ ndụ ihe nketa, dị ka nke ọma dị ka dị ọcha nketa nke alleles.

Na mfe version of meiosis dị mgbe e nwere nanị otu mmanya na akpa na-adọ, na nke abụọ e nwere crossover. Ọkà mmụta sayensị na-atụ aro na a n'ụdị bụ evolutionary precursor nke ot meiosis multicellular ntule. Ikekwe, e nwere ụzọ ndị ọzọ nke nuclear fission, nke ndị ọkà mmụta sayensị na-amabeghị.