Name: phragmoplast in plant cell division
Uploaded: 2023-04-30T18:28:51.000Z
Duration: 1 min 59 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Life Science

Inheritance and Variation of Traits

3.1.9-12.D

The Phragmoplast

As células vegetais são envolvidas por uma parede celular rígida, dificultando a divisão das células por contração externa. Assim, as células vegetais se dividem formando uma nova parede celular entre os dois núcleos-filhos de uma forma "de dentro para fora". Uma estrutura especializada em plantas chamada fragmoplasto orienta a formação da nova parede celular.
O plano de divisão celular, que é o futuro local de formação da parede celular, é marcado por uma banda pré-prófase composta de microtúbulos e filamentos de actina que se forma durante a fase G1 do ciclo celular. A banda de pré-prófase se reúne no córtex celular e desaparece no início da fase M.
Durante a mitose, os cromossomos se separam e começam a se mover para pólos opostos. Nos pólos, o envelope nuclear se forma ao redor dos cromossomos separados e os fusos começam a desaparecer. Os microtúbulos restantes do fuso mitótico formam o fragmoplasto.
Os microtúbulos do fragmoplasto são polares, com extremidades positivas próximas ao plano equatorial e extremidades negativas próximas aos pólos.
Os corpos de Golgi secretam pequenas vesículas que são transportadas por proteínas motoras ao longo dos microtúbulos até o centro da célula. Essas vesículas são preenchidas com polissacarídeos e glicoproteínas, dois componentes importantes necessários para a síntese de novas paredes celulares. A fusão de vesículas forma uma estrutura semelhante a um disco chamada placa celular inicial.
Os microtúbulos do fragmoplasto são regenerados com sucesso nas margens livres da placa celular, permitindo que o fragmoplasto estenda a placa lateralmente. A nova placa celular se une às paredes das células-mãe no local que foi marcado pela banda de pré-prófase antes da fase M. A membrana plasmática se funde com a placa celular e uma nova parede celular é formada, separando as duas células-filhas.

<ol>
	<li>Biologia Molecular da Célula, Alberts, 6ª edição. Páginas 997-999.</li>
	<li>Gaivota, Robert W. e B. Gunning. "O citoesqueleto da planta." Revisões críticas em ciências vegetais 8, nº 2 (1989): 131-167.</li>
	<li>Hamada, Takahiro. "Organização de microtúbulos e proteínas associadas a microtúbulos em células vegetais." Em Revisão Internacional de Biologia Celular e Molecular, vol. 312, pp. 1-52. Imprensa Acadêmica, 2014.</li>
	<li>Fosket, D. E. "Características das células vegetais que são importantes no desenvolvimento." Em Crescimento e Desenvolvimento de Plantas. Uma abordagem molecular. Imprensa Acadêmica San Diego, 1994.</li>
	<li>Casem, Merri Lynn, ed. Estudos de caso em biologia celular. Imprensa Acadêmica, 2016.</li>
</ol>

o fragmoplasto

A divisão celular é essencial para o crescimento e desenvolvimento do organismo. Nas células animais, o fuso central e suas proteínas associadas formam o meio do corpo, estrutura que desempenha um papel essencial na citocinese. Nas plantas, o fuso central, juntamente com os microtúbulos, a actina e outros componentes celulares, amadurece no fragmoplasto, que é necessário para a citocinese. Ao contrário do meio do corpo estacionário, o fragmoplasto se expande centrifugamente, levando eventualmente à formação da nova parede celular. O fragmoplasto maduro tem formato de donut e contém uma região líder externa, uma zona de transição intermediária e uma região atrasada interna. Na região líder, novos microtúbulos são montados continuamente. A nucleação dos microtúbulos é iniciada pelo complexo do anel γ-tubulina (γ-TuRC), que contém seis subunidades – GCP1 a GCP6. No entanto, o γ-TuRC não pode interagir diretamente com os microtúbulos; portanto, augmin, um complexo proteico que interage com microtúbulos, medeia o recrutamento de γ-TuRC para os microtúbulos. Os microtúbulos presentes no fragmoplasto atuam como trilhas para o transporte das vesículas secretoras produzidas pelo corpo de Golgi próximo. Na zona de transição intermediária, as vesículas inicialmente fazem a transição para estruturas semelhantes a túbulos e depois se interconectam para formar uma rede tubular entrelaçada. A adição contínua de vesículas secretoras resulta no crescimento externo da rede tubular até encontrar a membrana celular parental. As membranas das vesículas são usadas para formar a membrana plasmática das células-filhas, enquanto as biomoléculas presentes nas vesículas são usadas para construir a placa celular presente entre as membranas das duas células-filhas. Na região retardada, os microtúbulos se despolimerizam, deixando para trás a porção madura da placa celular. A placa celular totalmente formada posteriormente se desenvolve na parede celular que separa as duas células-filhas. A polimerização dos microtúbulos na extremidade dianteira e a despolimerização dos microtúbulos na região atrasada causam a expansão externa do fragmoplasto e da placa celular até que esta se junte à parede celular parental. A falha nas funções dos fragmoplastos pode resultar em células multinucleadas e fenótipos letais embrionários.

O Fragmoplasto

A divisão celular é essencial para o crescimento e desenvolvimento do organismo. Nas células animais, o fuso central e suas proteínas associadas formam o meio do corpo, um ...

Education

JoVE Core

Cell Biology

Biologia Celular

Unit 1

Unidade 1

Cell Division

Divisão Celular

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

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. It provides a framework for building the new partition between the cells. This makes it a key structure in plant cell division.

Phragmoplast in Plant 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

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

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

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 phragmoplast helps plant cells complete division by guiding cytokinesis and the formation of a new cell wall between daughter cells.

Phragmoplast in Plant Cell Division | 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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Cohesins

Condensins

The Mitotic Spindle

Centrosome Duplication

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Attachment of Sister Chromatids

Forces Acting on Chromosomes

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The Spindle Assembly Checkpoint

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Anaphase Promoting Complex

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Distribution of Cytoplasmic Content

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3.1.9-12.P

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3.1.9-12.Q

Phragmoplast in Plant Cell Division

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