Name: cell cycle checkpoints and cyclin control
Uploaded: 2025-05-22T09:05:54.000Z
Duration: 1 min 28 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Biology

BIO.6

BIO.6.A

The Cell Cycle Control System

Le système de contrôle du cycle cellulaire comporte des protéines régulatrices qui arrêtent le cycle cellulaire aux phases G1, G2 et mitotique.
Ils permettent d’éviter le lancement de l’étape suivante jusqu’à ce que les étapes précédentes soient terminées sans aucune erreur.
De plus, ces protéines régulatrices clés, appelées protéines kinases dépendantes des cyclines ou Cdk, forment des complexes avec les cyclines et garantissent que toutes les étapes sont coordonnées et correctement synchronisées.
Au point de contrôle G1, la protéine régulatrice vérifie si la cellule a atteint la taille critique, si l’ADN est exempt d’erreurs et si suffisamment de nutriments et de facteurs de croissance sont présents pour entrer dans la phase S pour la synthèse de l’ADN.
Si la cellule ne reçoit pas le signal nécessaire, elle passe à l’état de repos ou à la phase G0.
Sinon, l’ADN est répliqué et la cellule rencontre le point de contrôle G2, où les protéines régulatrices vérifient les erreurs dans l’ADN avant d’entrer en mitose.
Au cours de la mitose, une fois que la protéine régulatrice a vérifié que les chromosomes sont attachés au fuseau et qu’ils sont alignés avec précision, la cellule procède à la division.
À n’importe quel moment du cycle cellulaire, si la protéine régulatrice détecte des dommages irréparables, la mort cellulaire se produit.

le système de contrôle du cycle cellulaire

Le système de régulation du cycle cellulaire dirige la progression d'une cellule d'une phase à la suivante et commence la mitose. Le système de contrôle du cycle cellulaire comprend des molécules régulatrices intracellulaires et des déclencheurs externes. Ils fournissent des signaux "arrêt" ou "avance" et agissent à des stades spécifiques du cycle cellulaire appelés points de contrôle pour s'assurer qu'un processus particulier est terminé avant que la cellule ne passe à la phase suivante. Les cyclines et les kinases cycline-dépendantes (Cdks) sont les principaux régulateurs du cycle cellulaire et fonctionnent aux phases G1, G2 et M du cycle cellulaire. Les régulateurs au point de contrôle G1 vérifient que des conditions appropriées sont disponibles pour la synthèse de l'ADN, telles que la taille de la cellule et les facteurs de croissance. Si une cellule ne satisfait pas ces exigences, elle est empêchée d'entrer dans la phase S. La cellule arrête alors le cycle cellulaire ou passe à l'étape G0 jusqu'à ce que ses besoins soient satisfaits. Les régulateurs au point de contrôle G2 vérifient que l'ADN répliqué est exempt de dommages ou d'erreurs ; sinon, le mécanisme de réparation de l'ADN répare les dommages, puis permet à la cellule de progresser vers la prochaine étape. Les régulateurs du point de contrôle de la phase M s'assurent que les chromatides sœurs sont correctement alignées et attachées aux microtubules dans le plan équatorial de la métaphase. Cela permet à la cellule de passer à la phase anaphase de la division cellulaire et de produire deux cellules filles avec un nombre égal de chromosomes. Si une cellule échoue à l'un de ces points de contrôle et continue de progresser à travers la mitose, elle accumule des mutations qui peuvent éventuellement conduire à une croissance non contrôlée ou à la formation d'une tumeur. Ce texte est adapté de <a href="https://openstax.org/books/anatomy-and-physiology/pages/3-5-cell-growth-and-division">Openstax, Anatomy and Physiology 2e, Section 3.5: Section Title Cell Growth and Division</a>

Le système de contrôle du cycle cellulaire

La régulation du cycle cellulaire dirige la façon dont une cellule passe d’une phase à l’autre et commence la mitose. Le système de contrôle du cycle cellulaire comprend ...

Education

Enseignement

JoVE Core

Anatomy and Physiology

Anatomie et physiologie

Unit 1

Unité 1

Essential Cellular Processes

Processus cellulaires essentiels

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

cell cycle checkpoints and cyclin control

The cell cycle is controlled by checkpoints that help a cell move from one phase to the next and begin mitosis. This control system uses internal regulatory molecules and outside signals to send stop or advance instructions. It makes sure each step is finished before the cell moves forward.

Cyclins and cyclin-dependent kinases, or Cdks, are the main regulators of the cell cycle. They act during the G1, G2, and M phases. These regulators work at specific checkpoints to keep cell division orderly.

The G1 checkpoint checks whether the cell is ready for DNA synthesis. It looks at conditions such as cell size and growth factors. If these needs are not met, the cell does not enter S phase. Instead, it may pause the cycle or move into G0 until the conditions improve.

The G2 checkpoint reviews the replicated DNA before the cell moves on. It checks for damage or copying errors. If problems are found, DNA repair mechanisms fix the damage before the cell continues.

The M phase checkpoint acts during metaphase. It checks that sister chromatids are correctly aligned and attached to microtubules at the equatorial plane. When this happens, the cell can move into anaphase and form two daughter cells with the same number of chromosomes.

If a cell passes through these checkpoints without correction, mutations can build up. Over time, this may lead to uncontrolled growth or tumor formation. For that reason, cell cycle checkpoints are important for keeping division accurate.

Cell Cycle Checkpoints and Cyclin Control

cell-cycle-checkpoints-and-cyclin-control

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types of rna

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mitosis and cytokinesis

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the cell cycle control system

The cell cycle is controlled by checkpoints that help a cell move from one phase to the next and begin mitosis. This control system uses internal regulatory molecules and outside signals to send stop or advance instructions. It makes sure each step is finished before the cell moves forward. Cyclins and cyclin-dependent kinases, or Cdks, are the main regulators of the cell cycle. They act during the G1, G2, and M phases. These regulators work at specific checkpoints to keep cell division...

molecular factors affecting cell division

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overview of cell signaling

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cellular differentiation

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key terms and concepts

Explore how cyclins, Cdks, and checkpoints regulate the cell cycle at G1, G2, and M phases to protect DNA and guide normal cell division.

Cell Cycle Checkpoints and Cyclin Control | JoVE K12

anatomy and physiology

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

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 ...

Mitosis and Cytokinesis

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

Positive Regulator Molecules

To consistently produce healthy cells, the cell cycle&mdash;the process that generates daughter cells&mdash;must be precisely regulated.

Internal ...

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a ...

Cancer

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Replication in Prokaryotes

Overview

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Replication in Eukaryotes

Overview

In eukaryotic cells, DNA replication is highly conserved and tightly regulated. Multiple linear chromosomes must be duplicated with high ...

Proofreading

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Mitogens and the Cell Cycle

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The cell cycle regulation directs how a cell proceeds from one phase to the next and begins mitosis. The cell cycle control system includes intracellular ...

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Explain the process of cell specialization through cell differentiation, including the role of environmental factors.

BIO.6.B

Abnormal Proliferation

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Relate disruptions of the cell cycle to how they lead to the development of diseases such as cancer.

BIO.6.C

Science concepts--biological structures, functions, and processes. The student knows how an organism grows and the importance of cell differentiation. The student is expected to:

Cell Cycle Checkpoints and Cyclin Control

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