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

A segregação cromossômica ocorre durante a anáfase: quando as cromátides irmãs se separam e as cromátides individuais se movem em direção aos pólos opostos da célula.
A progressão da anáfase constitui dois processos independentes, mas sobrepostos: Anáfase A e Anáfase B.
Durante a anáfase A, na ausência de coesão da cromátide irmã, duas forças em direção aos pólos atuam nos cromossomos.
A despolimerização dos microtúbulos mais extremidades no cinetócoro produz uma força em direção aos pólos. O fluxo de microtúbulos, a partir da despolimerização da extremidade negativa, também gera uma força em direção aos pólos. A combinação dessas duas forças em direção aos pólos, acompanhada por um encurtamento dos microtúbulos cinetócoros, puxa as cromátides individuais em direção aos pólos do fuso.
À medida que os cromossomos filhos se movem em direção aos pólos, a anáfase B começa e os pólos do fuso são separados, alongando o fuso. As proteínas motoras, cinesina-5 e dineína, conduzem a separação dos pólos do fuso.
As proteínas motoras da cinesina-5 reticulam as extremidades positivas dos microtúbulos interpolares sobrepostos. Essas proteínas motoras direcionadas para a extremidade positiva geram uma força para trás ao longo dos microtúbulos, afastando os pólos do fuso. 
As proteínas motoras da dineína ligam as extremidades positivas dos microtúbulos astrais aos componentes do córtex celular. Essas proteínas motoras direcionadas para a extremidade negativa geram uma força, puxando os pólos do fuso em direção ao córtex celular.

<ol>
	<li>Alberts, Bruce. "Motores Moleculares." Biologia Molecular da Célula. 4ª edição. Biblioteca Nacional de Medicina dos EUA, 1º de janeiro de 1970. [<a href="https://www.ncbi.nlm.nih.gov/books/NBK26888/">Fonte</a>]</li>
	<li>Joglekar, Ajit P, Kerry S Bloom e Ed Salmon. 2010. "Mecanismos de geração de força por ligações de microtúbulos cinetócoros finais." Opinião atual em biologia celular 22 (1). Elsevier Ltd: 57–67. [<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2822009/">Fonte</a>]</li>
	<li>Khodjakov, Alexey e Tarun Kapoor. 2005. "Fluxo de microtúbulos: para que serve?" Biologia Atual 15 (23). Elsevier Inc: R966–R968. [<a href="https://www.sciencedirect.com/science/article/pii/S0960982205013928">Fonte</a>]</li>
</ol>

anáfase a e b

Os microtúbulos se formam através da polimerização ponta a ponta dos heterodímeros de tubulina. Os microtúbulos cinetocoros originam-se dos pólos do fuso e suas extremidades positivas se conectam aos cinetocoros nas cromátides irmãs. Os complexos proteicos Ndc80, presentes no cinetocoro, formam ligações de baixa afinidade com a extremidade positiva desses microtúbulos do cinetocoro. A despolimerização da extremidade positiva libera heterodímeros de tubulina da região terminal do microtúbulo. À medida que as subunidades de tubulina são perdidas, os complexos Ndc80 se desprendem e se reanexam em locais à frente do segmento despolimerizante do microtúbulo. O processo resulta em um deslocamento em direção aos pólos, puxando o cinetocoro e sua cromátide associada em direção ao pólo do fuso. O fluxo dos microtúbulos puxa as cromátides em direção aos pólos do fuso. As subunidades de tubulina que formam a estrutura dos microtúbulos movem-se continuamente em direção à extremidade negativa, exibindo um fluxo de microtúbulos direcionado à extremidade negativa. O fluxo de microtúbulos se desenvolve quando a despolimerização contínua na extremidade negativa é equilibrada pela polimerização contínua na extremidade positiva. Uma taxa constante de despolimerização e polimerização mantém um comprimento fixo de microtúbulos enquanto as subunidades individuais dentro da rede se movem em direção à extremidade de despolimerização. Os microtúbulos cinetocoros submetidos a fluxo puxam os cinetocoros e suas cromátides associadas ao longo da direção do fluxo, em direção aos pólos do fuso. Proteínas motoras de microtúbulos – Dynein e Kinesin-5 As dineínas são proteínas motoras dirigidas à extremidade negativa dos microtúbulos. As dineínas ligam as extremidades positivas dos microtúbulos astrais aos componentes do citoesqueleto no córtex celular, posicionando assim os pólos do fuso dentro da célula. O movimento direcionado para a extremidade negativa das dineínas gera uma força que puxa os pólos do fuso em direção ao córtex celular. Kinesin-5 são proteínas motoras direcionadas para a extremidade positiva. A cinesina-5 interage com as extremidades positivas dos microtúbulos interpolares antiparalelos na zona intermediária do fuso. Esses motores de microtúbulos ajudam os microtúbulos interpolares a deslizar uns pelos outros enquanto geram uma força que separa os pólos do fuso.

Anáfase A e B

Os microtúbulos se formam através da polimerização de ponta a ponta dos heterodímeros de tubulina. Os microtúbulos do cinetócoro se originam dos pólos do fuso e seus ...

Education

JoVE Core

Cell Biology

Biologia Celular

Unit 1

Unidade 1

Cell Division

Divisão Celular

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

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 - Biologia Celular ilustra processos celulares complexos em vídeos de animação fáceis de entender e, ao mesmo tempo, abrangentes. Esta coleção foca nos componentes e funções essenciais das células, incluindo organelas e membranas, transporte celular e energia celular. É complementado por vídeos de Cientistas em ação que demonstram a aplicação da biologia celular em experimentos de pesquisa do mundo real.

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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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 Migration

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Fate Mapping

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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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Chromosome Replication

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The Nucleosome

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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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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

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What is Meiosis?

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Meiosis II

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3.1.9-12.Q

Chromosome and Spindle Movement in Anaphase

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