Name: how the mitotic spindle guides cell division
Uploaded: 2025-05-22T09:05:47.000Z
Duration: 2 min 27 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Life Science

Inheritance and Variation of Traits

3.1.9-12.D

The Mitotic Spindle

Mitotik iğ, kardeş kromatitleri ayırır ve mitozun anafazı sırasında onları hücrenin zıt taraflarına hareket ettirir.
Mitotik milin temel yapıları, mikrotübül adı verilen içi boş silindirlerdir. Mitotik milin zıt uçlarında veya kutuplarında iki set mikrotübül düzenlenmiştir.
Her mikrotübülün bir eksi ucu ve bir artı ucu vardır. Mikrotübüllerin eksi uçları, iğ kutuplarının merkezinde buluşur. Artı uçlar kutuplardan dışa doğru uzanır.
Mitotik iğde farklı pozisyonlara ve rollere sahip farklı mikrotübül türleri vardır.
Kinetokor mikrotübülleri, artı uçlarından kinetokorlara bağlanarak kromozomları iğ kutbuna bağlar. Kinetokorlar, kardeş kromatitleri birbirine bağlayan özel bir DNA dizisi olan kromatid sentromerde bir araya getirilen büyük protein kompleksleridir.
Polarlar arası mikrotübüllerin düzenlenmesi, bir çift kenetlenmiş eli andırır. Bir interpolar mikrotübülün artı ucu, karşı kutuptan uzanan başka bir interpolar mikrotübülün artı ucu ile örtüşür. Motor proteinler, doğrudan iğ montajını sağlamak için polarlar arası mikrotübüllerle ilişkilidir.
Astral mikrotübüller, mili hücreye sabitler. Bu mikrotübüller topluca bir yıldız patlamasına benzer ve her bir pozitif uç, iğ kutbundan hücre korteksine doğru dışarı doğru çıkıntı yapar.
Çoğu hayvan hücresinde, mikrotübüller sentrozom adı verilen bir organel etrafında düzenlenir. Her iğ kutbunda bir sentrozom bulunur.
Bir sentrozom, perisentriyolar matris adı verilen şekilsiz bir protein kütlesi ile çevrili iki sentriolden oluşur. Sentrozom, hücredeki mikrotübülleri üretir, düzenler ve sabitler.
İki motor protein ailesi, mitotik iğin inşası ve çalışmasının ayrılmaz bir parçasıdır: kinesinle ilişkili proteinler ve dynein. Tipik olarak, kinesinle ilişkili proteinler mikrotübüllerin artı uçlarına doğru hareket eder ve dynein eksi uçlara doğru hareket eder.
Mitotik iğin ve mikrotübüllerinin içsel polaritesi, kromozomların mitotik ayrışmasını kolaylaştırarak hücreyi bölünmeye hazırlar.

<ol>
	<li>Heald, Rebecca ve Alexey Khodjakov. 2015. "Otuz Yıllık Arama ve Yakalama: Mitotik İğ Montajının Karmaşık Basitliği." Hücre Biyolojisi Dergisi 211 (6): 1103–11. <a href="https://doi.org/10.1083/jcb.201510015">https://doi.org/10.1083/jcb.201510015</a>.</li>
	<li>Petry, Sabine. 2016. "Mitotik İğ Düzeneğinin Mekanizmaları." Biyokimyanın Yıllık İncelemesi 85 (1): 659–83. <a href="https://doi.org/10.1146/annurev-biochem-060815-014528">https://doi.org/10.1146/annurev-biochem-060815-014528</a>.</li>
</ol>

mitotik İğ

Mitotik iğ— veya iğ aparatı— mikrotübüller adı verilen uzun protein liflerinden oluşan ökaryotik, hücre iskeleti yapısıdır. Hücre bölünmesi sırasında oluşan iğ, kardeş kromatitleri ayırır ve bunları ebeveyn hücrenin karşıt uçlarına doğru hareket ettirir; burada bireysel kromozomlar iki yavru hücre çekirdeğine dağıtılır. Mitotik iğin bipolar konfigürasyonu, kromozomal ayrışmayı kolaylaştırarak hücreyi bölünmeye hazırlar. Bipolar mitotik iğ oluşumunu sağlayan mekanizmalardan biri sentrozomlara dayanır. Omurgalı ovositleri ve daha yüksek bitki hücreleri gibi bazı hücrelerde sentrozom yoktur; ancak çoğu hayvan hücresinde mitoza girdiklerinde iki sentrozom bulunur. Her sentrozom, mitotik iğin karşıt uçlarında veya kutuplarında dairesel bir mikrotübül düzenlemesiyle birleşir. Başka bir deyişle sentrozomlar mikrotübülleri çekirdeklendirir. Motor proteinleri —özellikle kinesinler ve dinein— tipik olarak mikrotübüllerin uçlarında veya uçlarına yakın bir yerde çalışır ve bipolar mitotik iğ oluşumunu ve kardeş kromatitlerin ayrılmasını kolaylaştırır. Örneğin, iğ orta bölgesindeki kinesin-5 motorları, zıt iğ kutuplarından uzanan iki mikrotübüle bağlanır ve onları birbirinden ayırır; bu süreç, iğ kutuplarını birbirinden uzağa iterek iğ çift kutupluluğunu ve uzamasını destekler. Kinesin-5 aktivitesinin kinesin-14 ile dengelendiği düşünülmektedir. Kinesin-14 motorları zıt kutuplardan uzanan mikrotübülleri çekerek kutupları etkili bir şekilde bir araya getirir. Bu motorların koordineli faaliyeti, iğin doğru şekilde monte edilmesini sağlar. Kinesin-4 ve kinesin-10, kromokinesinlerdir. (Mitotik kromozomlarla ilişkilendirilebilen kinesinler) Kinesin-4 ve kinesin-10, kromozom kolları ile birleşerek kromozomları ve iğ kutbunu birbirinden uzaklaştırır. Dyneinler hücrenin çeşitli yerlerinde mikrotübülleri organize eder. Örneğin, astral mikrotübülleri aktin hücre iskeletine bağlayarak iğ kutuplarını birbirinden uzaklaştırırlar. Mitotik iğin yapısı, organizasyonu ve bileşenleri, kardeş kromatitlerin ayrılmasını sağlayarak hücreyi uygun bölünmeye hazırlar.

Mitotik İğ

Mitotik iğ veya iğ aparatı, mikrotübüller adı verilen uzun protein liflerinden oluşan ökaryotik, hücre iskeleti bir yapıdır. Oluşan...

Education

JoVE Core

Cell Biology

Hücre Biyolojisi

Unit 1

Ünite 1

Cell Division

Hücre Bölünmesi

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

how the mitotic spindle guides cell division

The mitotic spindle guides chromosome movement during cell division. It is a structure made of microtubules, which are thin protein fibers in the cell. These fibers organize and help separate the genetic material before the cell splits.

The spindle forms as the cell prepares to divide. Its fibers attach to chromosomes and line them up so they can be moved apart in an orderly way. This careful organization helps each new cell receive the correct set of chromosomes.

The mitotic spindle is a key part of mitosis, the process that produces two daughter cells from one parent cell. By directing chromosome separation, it supports accurate cell division in growing and repairing tissues. Understanding the spindle helps explain how cells copy themselves with precision.

How the Mitotic Spindle Guides Cell Division

how-the-mitotic-spindle-guides-cell-division

mitosis and cytokinesis

Stages of Cell Division in Eukaryotes

Cell division in eukaryotes follows a tightly regulated cycle that includes cell growth, DNA replication, chromosome duplication, chromosome distribution to daughter cells, and cell division. Regulatory systems and extracellular signals help control when cells divide. In typical human cells, the cycle takes about 24 hours. The cycle has two major stages. DNA is copied during the S phase of interphase. The mitotic, or M, phase then separates the duplicated chromosomes into two new nuclei and...

chromosome duplication

Chromosome Copying in Cell Division

Chromosome copying is an important step in cell division. Before a cell divides, it must make an exact copy of its chromosomes so each new cell can receive the same genetic information. A chromosome is a DNA-containing structure that carries genes. During duplication, the chromosome is copied into two identical sister chromatids. These copies stay attached until the cell is ready to separate them. This process helps ensure that daughter cells inherit a complete set of chromosomes. Accurate...

cohesins

Cohesins in Sister Chromatid Separation

Cohesins are protein complexes that help hold sister chromatids together after DNA is copied. They play a key role in cell division by keeping the two copies of a chromosome connected until the right time. These proteins act like a link between the sister chromatids. When the cell is ready to separate them, cohesins must be removed or released so each new cell can get one complete set of chromosomes. Cohesins are an important part of chromosome behavior during mitosis and meiosis. Their...

condensins

Condensin Proteins in Chromosome Packing

Condensin proteins help pack DNA into condensed chromosomes during cell division. They are part of the larger set of proteins that organize genetic material so it can be separated correctly when a cell divides. These proteins act by shaping and tightening chromosome structure. This process is important because DNA must be compacted before it can move through the stages of division. Condensins are therefore closely linked to chromosome condensation, the step that makes chromosomes more compact...

the mitotic spindle

The mitotic spindle guides chromosome movement during cell division. It is a structure made of microtubules, which are thin protein fibers in the cell. These fibers organize and help separate the genetic material before the cell splits. The spindle forms as the cell prepares to divide. Its fibers attach to chromosomes and line them up so they can be moved apart in an orderly way. This careful organization helps each new cell receive the correct set of chromosomes. The mitotic spindle is a key...

centrosome duplication

Centrosome Duplication in Cell Division

Centrosome duplication is an important step in cell division. The centrosome helps organize the cell’s internal structure, and it must be copied before a cell divides.

spindle assembly

Spindle Formation in Cell Division

Spindle formation in cell division is the process that builds the microtubule-based spindle needed to separate chromosomes. Microtubules are long protein fibers that help move and organize cell parts during division. During this process, microtubules grow and are arranged into a spindle structure around the chromosomes. The spindle forms in a way that supports chromosome movement to opposite sides of the cell. This step is essential for accurate cell division. Spindle formation depends on the...

attachment of sister chromatids

Sister Chromatid Attachment in Mitosis

Sister chromatid attachment in mitosis helps align duplicated chromosomes before they separate. Sister chromatids are the matching copies made after DNA replication. They stay connected until the cell is ready to divide. The attachment step is closely tied to the metaphase plate, the middle of the cell where chromosomes line up. This alignment helps each new cell receive one copy of every chromosome. Proper attachment is an important part of accurate cell division.

forces acting on chromosomes

Chromosome Movement During Cell Division

Chromosome movement during cell division depends on forces that act on the chromosomes. These forces help move the chromosomes into the right position as the cell divides. The transcript focuses on how these forces affect chromosome behavior during division. It highlights the role of the mitotic spindle, which is the structure that helps organize and move chromosomes. The spindle uses force to guide chromosome movement at the right time. Understanding these forces helps explain how...

separation of sister chromatids

Chromatid Pulling in Cell Division

Separation of sister chromatids is a key step in cell division. Sister chromatids are two identical copies of a chromosome that stay attached until the cell is ready to split them apart. Their separation helps each new cell receive the correct genetic material. During this stage, the sister chromatids are pulled to opposite sides of the cell. This movement happens as the cell prepares to divide into two daughter cells. Once the chromatids separate, each side of the cell has a complete set of...

the spindle assembly checkpoint

How Cells Verify Chromosome Spindle Attachment

The spindle assembly checkpoint helps cells verify that chromosomes are attached to the spindle before division continues. It acts as a safety step during cell division and helps prevent errors in chromosome separation. This checkpoint is controlled by kinetochores, which are protein structures on chromosomes that connect to spindle fibers. If a chromosome is not attached correctly, the checkpoint can delay progression until the problem is fixed. Once the attachment is correct, the cell can...

anaphase a and b

Chromosome and Spindle Movement in Anaphase

Anaphase is the stage of cell division when chromosomes move apart. In this phase, sister chromatids separate and travel toward opposite poles of the cell. Chromosome movement in anaphase can happen in two ways. In anaphase A, chromosomes move closer to the poles as the microtubules attached to them shorten. In anaphase B, the spindle poles themselves move farther apart and help stretch the cell. These two movements work together to ensure that the separated chromosomes are pulled to opposite...

anaphase promoting complex

Cell Cycle Control by APC

The anaphase-promoting complex, or APC, helps control cell cycle progression. It acts during cell division to help move the process from one stage to the next. This control is important for proper timing in the cell cycle. APC is a protein complex that works as a regulator. It helps trigger key steps that allow division to continue in an ordered way. By guiding this transition, APC supports normal cell cycle control.

the contractile ring

Cell Division and the Contractile Ring

The contractile ring helps cells divide at the end of cell division. It forms at the cell's center and tightens to split one cell into two. This process is part of cytokinesis, the stage when the cytoplasm divides. The ring is made of actin and myosin, two proteins that can work together to create force. As the ring contracts, it draws the cell membrane inward. This pinch helps separate the two daughter cells. Understanding the contractile ring is important for studying how cells complete...

determining the plane of cell division

Spindle Position and Cell Division Plane

The plane of cell division is set by the position of the spindle during mitosis. Cells use this internal structure to help decide where the cell will split. The result affects how the two daughter cells are arranged after division. This process is important in many developing tissues. It helps explain how cells divide in a controlled direction. A clear plane of division supports proper cell organization as new cells form. The transcript focuses on how the spindle is used to determine that...

the phragmoplast

Phragmoplast in Plant Cell Division

The phragmoplast is a plant cell structure that forms during cell division. It helps guide the final stage of division, when the cell begins to split into two daughter cells. In plant cells, the phragmoplast appears between the two new nuclei. It is part of the process that leads to the formation of a new cell wall. This wall separates the daughter cells after division is complete. The phragmoplast plays an important role in plant cytokinesis, which is the physical division of the cytoplasm.

distribution of cytoplasmic content

Cytoplasmic Content During Cell Division

Cytoplasmic content is distributed as a cell divides. This process helps each new cell receive the materials it needs to function. The cytoplasm includes the fluid and structures inside the cell membrane, but outside the nucleus. During cell division, this content is separated between the two daughter cells. The division must be organized so both cells can continue normal activity after the split. The video focuses on how this distribution occurs as part of cell division. It highlights the...

key terms and concepts

Learn how the mitotic spindle uses microtubules to line up and separate chromosomes during mitosis so each daughter cell gets the right genetic material.

How the Mitotic Spindle Guides Cell Division | JoVE K12

cell biology

JoVE Core Hücre Biyolojisi, anlaşılması kolay ancak kapsamlı animasyonlu video derslerde karmaşık hücresel süreçleri gösterir. Bu koleksiyon, organeller ve zarlar, hücresel taşıma ve hücre enerjileri dahil olmak üzere hücrelerin temel bileşenlerine ve işlevlerine odaklanır. Gerçek dünya araştırma deneylerinde hücre biyolojisinin uygulanmasını gösteren bilim insanı eylem videoları ile tamamlanmaktadır.

Louisiana Student Standards for Science

High School

Life Sciences

from-molecules-to-organisms-structures-and-processes

From Molecules To Organisms: Structures And Processes

HS-LS1-4

Tennessee Academic Standards

Biology

From Molecules to Organisms: Structures and Processes

BIO1.LS1.6

Minnesota Academic Standards in Science

3.1.1 9L.3.1.1.2

new-jersey-student-learning-standards-for-science

New Jersey Student Learning Standards for Science

Arizona Science Standards

HS+B.L1

HS+B.L1U1.9

Alabama Course of Study Science

9-12.B.1.3

Next Generation Science Standards

Florida Department of Education

SC.912.L.16

SC.912.L.16.14

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

B-LS1-4.

new-york-state-science-learning-standards

New York State Science Learning Standards

HS-LS1-4.

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Interphase

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Positive Regulator Molecules

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Chromosome Duplication

Cohesins

Condensins

Centrosome Duplication

Spindle Assembly

Attachment of Sister Chromatids

Forces Acting on Chromosomes

Separation of Sister Chromatids

The Spindle Assembly Checkpoint

Anaphase A and B

Anaphase Promoting Complex

The Contractile Ring

Determining the Plane of Cell Division

The Phragmoplast

Distribution of Cytoplasmic Content

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Cell Cycle Analysis

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DNA Packaging

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Chromatin Packaging

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Karyotyping

Proteins: From Genes to Degradation

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3.1.9-12.P

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3.1.9-12.Q

How the Mitotic Spindle Guides Cell Division

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