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

La segregación cromosómica tiene lugar durante la anafase: cuando las cromátidas hermanas se separan y las cromátidas individuales se mueven hacia los polos opuestos de la célula.
La progresión de la anafase constituye dos procesos independientes pero superpuestos: la anafase A y la anafase B.
Durante la anafase A, en ausencia de cohesión de cromátidas hermanas, dos fuerzas polares actúan sobre los cromosomas.
La despolimerización del extremo positivo de los microtúbulos en el cinetocoro produce una fuerza hacia los polos. El flujo de microtúbulos, de la despolimerización del extremo negativo, también genera una fuerza hacia los polos. La combinación de estas dos fuerzas hacia los polos, acompañada de un acortamiento de los cinetocoros-microtúbulos, tira de las cromátidas individuales hacia los polos del huso.
A medida que los cromosomas hijos se mueven hacia los polos, comienza la anafase B y los polos del huso se separan, alargando el huso. Las proteínas motoras, la kinesina-5 y la dineína, impulsan la separación de los polos del huso.
Las proteínas motoras de la kinesina-5 entrecruzan los extremos positivos de los microtúbulos interpolares superpuestos. Estas proteínas motoras dirigidas al extremo positivo generan una fuerza hacia atrás a lo largo de los microtúbulos que separan los polos del huso. 
Las proteínas motoras de dineína unen los extremos positivos de los microtúbulos astrales con los componentes de la corteza celular. Estas proteínas motoras dirigidas al extremo negativo generan una fuerza que tira de los polos del huso hacia la corteza celular.

<ol>
	<li>Alberts, Bruce. "Motores moleculares". Biología Molecular de la Célula. 4ª edición. Biblioteca Nacional de Medicina de los Estados Unidos, 1 de enero de 1970. [<a href="https://www.ncbi.nlm.nih.gov/books/NBK26888/">Fuente</a>]</li>
	<li>Joglekar, Ajit P, Kerry S Bloom y Ed Salmon. 2010. "Mecanismos de generación de fuerza por uniones de cinetocoro-microtúbulos extremos." Opinión actual en biología celular 22 (1). Elsevier Ltd: 57–67. [<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2822009/">Fuente</a>]</li>
	<li>Khodjakov, Alexey y Tarun Kapoor. 2005. "Flujo de microtúbulos: ¿Para qué sirve?" Current Biology 15 (23). Elsevier Inc.: R966–R968. [<a href="https://www.sciencedirect.com/science/article/pii/S0960982205013928">Fuente</a>]</li>
</ol>

anafase a y b

Los microtúbulos se forman mediante la polimerización de extremo a extremo de heterodímeros de tubulina. Los microtúbulos cinetocoros se originan en los polos del huso y sus extremos positivos se conectan con los cinetocoros de las cromátidas hermanas. Los complejos proteicos Ndc80, presentes en el cinetocoro, forman enlaces de baja afinidad con el extremo positivo de estos microtúbulos del cinetocoro.

La despolimerización del extremo positivo libera heterodímeros de tubulina de la región terminal del microtúbulo. A medida que se pierden las subunidades de tubulina, los complejos Ndc80 se desprenden y se vuelven a unir en sitios delante del segmento despolimerizante del microtúbulo. El proceso da como resultado un desplazamiento hacia los polos, tirando del cinetocoro y su cromátida asociada hacia el polo del huso.

El flujo de microtúbulos atrae las cromátidas hacia los polos del huso.

Las subunidades de tubulina que forman la red de microtúbulos se mueven continuamente hacia el extremo negativo, exhibiendo un flujo de microtúbulos dirigido al extremo negativo.

El flujo de microtúbulos se desarrolla cuando la despolimerización continua en el extremo negativo se equilibra con la polimerización continua en el extremo positivo. Una tasa constante de despolimerización y polimerización mantiene una longitud fija de los microtúbulos mientras las subunidades individuales dentro de la red se mueven hacia el extremo despolimerizante.

Los microtúbulos cinetocoros sometidos a flujo atraen a los cinetocoros y sus cromátidas asociadas a lo largo de la dirección del flujo, hacia los polos del huso.

Proteínas motoras de microtúbulos: dineína y kinesina-5

Las dineínas son proteínas motoras dirigidas al extremo negativo de los microtúbulos. Las dineínas unen los extremos positivos de los microtúbulos astrales con los componentes citoesqueléticos de la corteza celular, posicionando así los polos del huso dentro de la célula. El movimiento dirigido por el extremo negativo de las dineínas genera una fuerza que atrae los polos del huso hacia la corteza celular.

Kinesin-5 son proteínas motoras dirigidas al extremo positivo. Kinesin-5 interactúa con los extremos positivos de los microtúbulos interpolares antiparalelos en la zona media del huso. Estos motores de microtúbulos ayudan a los microtúbulos interpolares a deslizarse unos sobre otros mientras generan una fuerza que separa los polos del huso.

Anafase A y B

Los microtúbulos se forman a través de la polimerización de extremo a extremo de los heterodímeros de tubulina. Los microtúbulos del cinetocoro se originan en los polos del huso, y su ...

Education

Educación

JoVE Core

Cell Biology

Biología Celular

Unit 1

Unidad 1

Cell Division

División celular

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

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 Biología Celular ilustra procesos celulares complejos mediante completos vídeos animados fáciles de entender. Esta colección se centra en los componentes esenciales de las células y su funcionamiento, incluyendo los orgánulos y las membranas, el transporte celular y el metabolismo energético celular. Todo este material se complementa con los vídeos de científicos en acción, que muestran la aplicación de la biología celular en experimentos reales de investigación.

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.

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Condensins

The Mitotic Spindle

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3.1.9-12.Q

Chromosome and Spindle Movement in Anaphase

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