Name: chromosome copying in cell division
Uploaded: 2023-04-30T18:28:50.000Z
Duration: 2 min 5 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Life Science

Inheritance and Variation of Traits

3.1.9-12.D

Chromosome Duplication

真核细胞中的遗传物质DNA存在于细胞核内，呈线性结构，称为染色体。
在染色体中，双链DNA主要缠绕在称为组蛋白的八聚体核蛋白上，形成核小体。多种非组蛋白也与DNA结合，协助DNA的包装。
这些核小体和非组蛋白折叠形成螺旋结构，进一步盘绕成环状，在阵列中构成致密的染色质。染色质压缩的程度使得极长的DNA能够容纳在细胞核内。在M期，染色质进一步螺旋化，形成凝缩的染色体。
染色体复制涉及整个染色质结构的复制，因此DNA和与染色质相关的蛋白质都会被复制。组蛋白的合成增加，以生成将新合成的DNA包装成染色体所需的额外蛋白质。
复制染色体精确的染色质结构对于基因调控至关重要。&#160;
在染色体内部，染色质的包装程度并不总是均匀的。染色体包含一些染色质紧密包装的区域，称为异染色质，以及一些染色质松散包装的区域，称为常染色质。
异染色质DNA无法被转录机制接近，因此这些区域的基因通常不会被转录。相反，常染色质内的DNA更具可接近性，因此这些区域的基因可以被转录。
染色质的这种结构和功能重要性使得在整个染色体复制过程中准确复制整个染色质结构变得至关重要。

<ol>
	<li>Groth、Anja、Walter Rocha、Alain Verreault 和 Geneviève Almouzni。"DNA 复制和修复过程中的染色质挑战。"细胞 128 （4）2007:721-33。[<a href="https://www.sciencedirect.com/science/article/pii/S0092867407001298">来源</a>]</li>
	<li>Margueron、Raphaël 和 Danny Reinberg。"染色质结构和表观遗传信息的遗传。"自然评论遗传学 11 （4）2010:285-96。[<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3760772/">来源</a>]</li>
</ol>

染色体复制

细胞分裂过程中染色体复制的过程需要全基因组的破坏和染色质的重新组装。 染色质结构必须在子细胞中准确遗传、重新组装和维持，以确保谱系繁殖。

染色质的基本单位是核小体，由包裹八聚组蛋白的 DNA 和分隔各个核小体的短连接 DNA 组成。 核小体内的组蛋白的 N 末端伸出核心，为调节染色质结构和功能的各种共价修饰提供位点。

在复制过程中，随着 DNA 解旋，亲代核小体被破坏，组蛋白被释放。 随着复制的进行和子链的形成，亲代组蛋白和 S 期合成的其他组蛋白被组装，从而形成核小体。

DNA 中组蛋白和其他表观遗传域的翻译后修饰也忠实地在子代基因组中复制。

染色质结构影响基因表达

在细胞内，转录因子仍然无法接触到基因组的主要部分，因为调控和编码 DNA 序列大多隐藏在核小体中。 为了使基因表达，必须为转录因子结合创造可及的位点，并修饰组蛋白以重组染色质结构并创造允许转录的环境。

特定的调节因子复合物参与通过核小体的移位或破坏来打开染色质的局部区域。 组蛋白尾部的翻译后修饰用于维持活性或非活性转录状态。 组蛋白尾部的特定修饰可以缓解 DNA 压缩水平，促进核小体的不稳定和移位，为转录机制影响基因表达提供途径。

细胞分裂过程中染色体复制需要全基因组范围内染色质的解聚与重新组装。染色质结构必须……

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

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 chromosome copying is essential for normal growth, repair, and reproduction in living organisms.

Chromosome Copying in 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 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

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 chromosome copying works before cell division and how sister chromatids help daughter cells inherit the same genetic information.

Chromosome Copying in Cell Division | 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

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.

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

The cell cycle occurs over approximately 24 hours (in a typical human cell) and in two distinct stages: interphase, which includes three phases of the ...

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 ...

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 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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Cleavage and Blastulation

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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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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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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

Genomic DNA in Prokaryotes

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Binary Fission

Fission is the division of a single entity into two or more parts, which regenerate into separate entities that resemble the original. Organisms in the ...

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 Copying in Cell Division

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