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

The cell cycle control system features regulatory proteins that halt the cell cycle at G1 , G2, and mitotic phases.
They help prevent the initiation of the next stage until the earlier stages are completed without any error.
In addition, these key regulator proteins, called the cyclin-dependent protein kinases or Cdks, form complexes with cyclins and ensure all the stages are coordinated and correctly timed.
At the G1 checkpoint, the regulatory protein checks if the cell has reached the critical size, the DNA is error-free, and sufficient nutrients and growth factors are present to enter the S phase for DNA synthesis.
If the cell does not receive the necessary signal, it switches to a resting state or G0 phase.
Otherwise, the DNA is replicated, and the cell encounters the G2 checkpoint, where the regulatory proteins check for errors in the DNA before entering mitosis.
During mitosis, after the regulatory protein verifies that the chromosomes are attached to the spindle and are accurately aligned, the cell proceeds to division.
At any point in the cell cycle, if the regulatory protein detects irreparable damage, cell death occurs.

het systeem voor de regulering van de celcyclus

Het systeem voor de regulering van de celcyclus bepaalt hoe een cel van de ene fase naar de volgende gaat en mitose start. Het systeem omvat intracellulaire regulerende moleculen en externe prikkels. Ze geven "stop" of "doorgaan" signalen en werken bij specifieke controlepunten in de celcyclus om ervoor te zorgen dat een bepaald proces is voltooid, voordat de cel doorgaat naar de volgende fase.

Cyclines en cycline-afhankelijke kinasen (Cdks) zijn de belangrijkste regulerende moleculen van de celcyclus en functioneren in de G1, G2 en M fasen van de celcyclus. De regulerende moleculen bij het G1-controlepunt controleren of de juiste omstandigheden beschikbaar zijn voor DNA-synthese, zoals celgrootte en groeifactoren. Als een cel niet aan deze vereisten voldoet, wordt voorkomen dat deze de S-fase binnengaat. De cel stopt dan de celcyclus of gaat naar de G0-fase totdat aan haar behoeften is voldaan. De regulerende moleculen bij het G2-controlepunt controleren of het gerepliceerde DNA vrij is van schade of fouten; indien nodig repareert het DNA-herstelmechanisme de schade en staat het dan de cel toe om naar de volgende fase te gaan. De regulerende moleculen bij het M-fase controlepunt zorgen ervoor dat de zusterchromatiden correct zijn uitgelijnd en verbonden met de microtubuli in het equatoriale vlak van de metafase. Dit stelt de cel in staat om door te gaan naar de anafasefase van celdeling en twee dochtercellen te produceren met een gelijk aantal chromosomen.

Als een cel een van de bovengenoemde controlepunten niet doorstaat, en doorgaat met mitose, hoopt het mutaties op die uiteindelijk kunnen leiden tot ongecontroleerde groei of tumoren.

Deze tekst is aangepast van <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>

Het systeem voor de regulering van de celcyclus

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 ...

Education

JoVE Core

Anatomy and Physiology

Anatomie en fysiologie

Unit 1

Essential Cellular Processes

Essentiële cellulaire processen

KEY TERMS AND CONCEPTS

BELANGRIJKE TERMEN EN CONCEPTEN

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

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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...

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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.

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Replication in Prokaryotes

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BIO.6.B

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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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