Name: chromosome and spindle movement in anaphase
Uploaded: 2023-04-30T18:28:50.000Z
Duration: 1 min 39 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Life Science

Inheritance and Variation of Traits

3.1.9-12.D

Anaphase A and B

染色体分离发生在有丝分裂的后期：此时姐妹染色单体分开，单个染色单体向细胞的两极移动。
后期进程包含两个独立但重叠的过程：后期A和后期B。
在A期后期，由于姐妹染色单体无黏连，两种向极作用力作用于染色体上。
动粒处微管正端的去聚合产生向极的力。微管从负端去聚合产生的通量也生成向极的力。这两种向极力的共同作用，伴随动粒微管的缩短，将单个染色单体拉向纺锤体极。
当子染色体向两极移动时，后期B开始，纺锤体极分离，导致纺锤体延长。驱动蛋白kinesin-5和动力蛋白dynein介导了纺锤体极的分离。
驱动蛋白-5（kinesin-5）马达蛋白可交联重叠的极间微管的正端。这些朝向正端运动的马达蛋白沿微管产生向后的作用力，推动纺锤体两极分离。&#160;
动力蛋白（dynein）将星体微管的正端与细胞皮层组分连接起来。这些向负端移动的马达蛋白产生拉力，将纺锤体极拉向细胞皮层。

<ol>
	<li>阿尔伯茨，布鲁斯。"分子马达。细胞分子生物学。第 4 版。美国国家医学图书馆，1970 年 1 月 1 日。[<a href="https://www.ncbi.nlm.nih.gov/books/NBK26888/">来源</a>]</li>
	<li>Joglekar、Ajit P、Kerry S Bloom 和 Ed Salmon。2010. "末端着丝粒-微管附着产生力的机制。"细胞生物学最新观点 22 （1）。爱思唯尔有限公司:57-67。[<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2822009/">来源</a>]</li>
	<li>霍贾科夫、阿列克谢和塔伦·卡普尔。2005. "微管通量:它有什么好处？"当代生物学 15 （23）。爱思唯尔公司:R966–R968。[<a href="https://www.sciencedirect.com/science/article/pii/S0960982205013928">来源</a>]</li>
</ol>

a相与b相分离

微管通过微管蛋白异二聚体的端对端聚合形成。 着丝粒微管起源于纺锤体极，其正端与姐妹染色单体上的着丝粒连接。 存在于着丝粒上的 Ndc80 蛋白复合物与这些着丝粒微管的正端形成低亲和力连接。

正末端解聚从微管的末端区域释放微管蛋白异二聚体。 当微管蛋白亚基丢失时，Ndc80 复合物在微管解聚片段之前的位点分离并重新附着。 该过程导致向极移动，将动粒及其相关染色单体拉向纺锤体极。

微管通量将染色单体拉向纺锤体两极。

形成微管晶格的微管蛋白亚基连续向负端移动，表现出负端定向的微管通量。

当负端的连续解聚与正端的连续聚合平衡时，微管通量就会产生。 恒定的解聚和聚合速率保持固定的微管长度，同时晶格内的各个亚基向解聚端移动。

经历通量的着丝粒微管将着丝粒及其相关染色单体沿着通量的方向拉向纺锤体极。

微管运动蛋白 – 动力蛋白和驱动蛋白-5

动力蛋白是微管负端定向运动蛋白。 动力蛋白将星体微管的正端与细胞皮质中的细胞骨架成分连接起来，从而将纺锤体极定位在细胞内。 动力蛋白的负端定向运动产生一种力，将纺锤体极拉向细胞皮层。

Kinesin-5 是正端定向运动蛋白。 驱动蛋白-5 与纺锤体中区反平行极间微管的正端相互作用。 这些微管马达帮助极间微管彼此滑动，同时产生推动纺锤体两极分开的力。

A相与B相分离

微管通过微管蛋白异源二聚体的首尾相连聚合形成。动粒微管起源于纺锤体极，其……

Education

教育

JoVE Core

Cell Biology

细胞生物学

Unit 1

第一单元

Cell Division

细胞分裂

KEY TERMS AND CONCEPTS

关键术语与概念

后期 A 和 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 sides. The result is a more even distribution of genetic material before the cell finishes dividing.

Chromosome and Spindle Movement in Anaphase

chromosome-and-spindle-movement-in-anaphase

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

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...

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

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 anaphase A and anaphase B move chromosomes apart during cell division, with sister chromatids separating and spindle poles shifting to opposite sides.

Chromosome and Spindle Movement in Anaphase | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

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

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.

What is the Cell Cycle?

The cell cycle refers to the sequence of events occurring throughout a typical cell&#8217;s life. In eukaryotic cells, the somatic cell cycle has two ...

Interphase

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The Cell Cycle Control System

Positive Regulator Molecules

Inhibition of CDK Activity

Mitosis and Cytokinesis

In eukaryotes, the cell division cycle is divided into distinct, coordinated cellular processes that include cell growth, DNA replication/chromosome ...

Chromosome Duplication

Cohesins

Condensins

The Mitotic Spindle

Centrosome Duplication

Spindle Assembly

Attachment of Sister Chromatids

Forces Acting on Chromosomes

Separation of Sister Chromatids

The Spindle Assembly Checkpoint

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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Fertilization

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Cleavage and Blastulation

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Gastrulation

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Neurulation

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Cell Migration

Cell migration, the process by which cells move from one location to another, is essential for the proper development and viability of organisms ...

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An Introduction to Organogenesis

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Fate Mapping

Fate mapping is a technique used to understand how embryonic cells divide, differentiate, and migrate during development. In classic fate mapping ...

Students who demonstrate understanding can use a model to illustrate the role of cellular division (mitosis) and differentiation in producing and maintaining complex organisms.  Assessment Boundary: Assessment does not include specific gene control mechanisms or rote memorization of the steps of mitosis.

DNA Packaging

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Organization of Genes

Structure of a Gene

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Chromosome Structure

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The centromere is a DNA ...

Chromosome Replication

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The Nucleosome

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Chromatin Packaging

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Karyotyping

Proteins: From Genes to Degradation

The DNA Helix

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The Central Dogma

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RNA is the Missing Link Between ...

Mutations

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genome-size-and-the-evolution-of-new-genes

Genome Size and the Evolution of New Genes

Gene Families

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3.1.9-12.P

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Binary Fission

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Genomic DNA in Eukaryotes

Eukaryotes have large genomes compared to prokaryotes. To fit their genomes into a cell, eukaryotic DNA is packaged extraordinarily tightly inside the ...

What is Meiosis?

Meiosis is the process by which diploid cells divide to produce haploid daughter cells. In humans, each diploid cell contains 46 chromosomes, half from ...

Meiosis I

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Meiosis II

Meiosis II is the second and final stage of meiosis. It relies on the haploid cells produced during meiosis I, each of which contain only 23 ...

Students who demonstrate understanding can make and defend a claim based on evidence that inheritable genetic variations may result from (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors. Assessment Boundary: Assessment does not include the phases of meiosis or the biochemical mechanism of specific steps in the process.

3.1.9-12.Q

Chromosome and Spindle Movement in Anaphase

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