Name: cell cycle checkpoints and cancer
Uploaded: 2025-08-06T09:37:54.000Z
Duration: 1 min 4 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

North Carolina K-12 Science Standard Course of Study

9-12

Biology

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms- Structures and Processes

LS.Bio.2.1

What is the Cell Cycle?

[Istruttore] Il ciclo cellulare
si riferisce alla serie

di eventi che avvengono nel
ciclo vitale di una cellula,

inclusa la crescita, la
replicazione del DNA,

in alcuni casi, ulteriore
crescita e divisione.

Per gli organismi che si
riproducono sessualmente

la vita inizia come uno
zigote, un uovo fecondato.

Col tempo, la singola cellula
originale cresce e si divide

in maniera graduale e produce

un individuo complesso e multicellulare.

Le cellule continuano questo
processo per mantenere

e riparare i tessuti durante
la crescita dell'individuo.

Al contrario, gli organismi unicellulari,

come i batteri, si basano
sulla divisione cellulare

per riprodursi semplicemente
attraverso la fissione binaria.

Purtroppo, quando la divisione
cellulare non é controllata,

il cancro risulta, con
una perdita di controllo

su sequenze genomiche che
regolano il processo normale.

Sherr, Charles J. e Jiri Bartek. "Terapie antitumorali mirate al ciclo cellulare". Rassegna annuale di biologia del cancro 1, n. 1 (2017): 41–57. [<a href="https://doi.org/10.1146/annurev-cancerbio-040716-075628" target="__blank">Sorgente</a>]

cos'è il ciclo cellulare

Il ciclo cellulare si riferisce alla sequenza di eventi che si verificano nel corso della vita di una cellula tipica. Nelle cellule eucariotiche, il ciclo delle cellule somatiche ha due fasi: l'interfase e la fase mitotica. Durante l'interfase, la cellula cresce, svolge le sue funzioni metaboliche di base, copia il suo DNA e si prepara per la divisione delle cellule mitotiche. Quindi, durante la mitosi e la citocinesi, la cellula divide rispettivamente i suoi materiali nucleari e citoplasmatici. Questo genera due celle figlio che sono identiche alla cella padre originale. Il ciclo cellulare è essenziale per la crescita dell'organismo, la sostituzione delle cellule danneggiate e la rigenerazione delle cellule invecchiate. Il cancro è il risultato di una divisione cellulare incontrollata innescata da una mutazione genica.

<h4>Checkpoint del ciclo cellulare</h4>

Ci sono tre punti di controllo principali nel ciclo cellulare eucacotico. Ad ogni checkpoint, la progressione alla fase successiva del ciclo cellulare può essere interrotta fino a quando le condizioni sono più favorevoli. Il checkpoint G1 è il primo di questi, dove vengono valutate le dimensioni, l'energia, i nutrienti, la qualità del DNA e altri fattori esterni di una cellula. Se la cellula è ritenuta inadeguata, non prosegue fino alla fase S dell'interfase. Il checkpoint G2 è il secondo checkpoint. Qui, la cellula assicura che tutto il DNA sia stato replicato e non venga danneggiato prima di entrare nella mitosi. Se viene rilevato un danno al DNA che non può essere riparato, la cellula può subire apoptosi o morte cellulare programmata. Il checkpoint M, o mandrino, assicura che tutte le cromatidi sorelle siano correttamente attaccate ai microtubuli del mandrino nella piastra della metafase prima che la cellula entri in anafase.

<h4>Cancro: Quando il ciclo cellulare va storto</h4>

I punti di controllo del ciclo cellulare assicurano che le cellule sane si spostino attraverso il ciclo cellulare in modo regolamentato. Tuttavia, le cellule tumorali spesso bypassano questi checkpoint. Ogni ciclo successivo di divisione cellulare non controllata produce cellule figlie più danneggiate. Inoltre, le cellule tumorali nel corpo umano possono dividere molte più volte rispetto alle cellule normali, che possono subire solo circa 40-60 cicli di divisione. Le cellule tumorali esprimono la telomerasi, un enzima che ripara l'usura alle estremità dei cromosomi che è tipicamente causata dalla divisione cellulare.

Cos'è il ciclo cellulare

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 ...

Education

Didattica

JoVE Core

Biologia

Cellular Processes

Processi cellulari

Cell Cycle and Division

Ciclo e divisione cellulare

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

cell cycle checkpoints and cancer

The cell cycle is the set of steps a eukaryotic cell follows as it grows and divides. In somatic cells, it has two main stages: interphase and the mitotic phase. During interphase, the cell grows, carries out its basic metabolic functions, copies its DNA, and gets ready for mitotic cell division.

After interphase, the cell enters mitosis and cytokinesis. Mitosis divides the nuclear material, and cytokinesis divides the cytoplasm. These steps produce two daughter cells that are identical to the original parent cell.

The cell cycle is important for many body processes. It supports growth, replaces damaged cells, and helps regenerate older cells. When the cycle is disrupted by a gene mutation, uncontrolled cell division can lead to cancer.

Eukaryotic cells also use checkpoints to control cell cycle progress. The G1 checkpoint checks cell size, energy, nutrients, DNA quality, and other external factors before the cell enters S phase. The G2 checkpoint confirms that DNA has been fully copied and is not damaged before mitosis begins. If damage cannot be repaired, the cell may undergo apoptosis, or programmed cell death.

The M checkpoint, also called the spindle checkpoint, acts during mitosis. It makes sure the sister chromatids are properly attached to spindle microtubules at the metaphase plate before anaphase starts. These checkpoints help healthy cells divide in a regulated way, but cancer cells often bypass them. As a result, each round of unchecked division can create more damaged daughter cells, and cancer cells may divide far more times than normal cells, which usually complete about 40 to 60 divisions. Cancer cells also express telomerase, an enzyme that helps repair chromosome ends worn down by repeated cell division.

Cell Cycle Checkpoints and Cancer

what is the cell cycle?

The cell cycle is the set of steps a eukaryotic cell follows as it grows and divides. In somatic cells, it has two main stages: interphase and the mitotic phase. During interphase, the cell grows, carries out its basic metabolic functions, copies its DNA, and gets ready for mitotic cell division. After interphase, the cell enters mitosis and cytokinesis. Mitosis divides the nuclear material, and cytokinesis divides the cytoplasm. These steps produce two daughter cells that are identical to the...

genomic dna in prokaryotes

Prokaryote Chromosomes and Plasmids

Most prokaryotes store their DNA in one circular chromosome inside the nucleoid, a region of cytoplasm. This chromosome is double-stranded and tightly wound, or supercoiled, so it fits efficiently inside the cell. Prokaryotes also carry smaller circular DNA pieces called plasmids. Plasmids often carry genes that give bacteria helpful traits. One important example is antibiotic resistance. Bacteria can gain these plasmids and the traits they carry, which can help them adapt to changing...

binary fission

How Cells Split by Binary Fission

Binary fission is a common way that bacteria and archaea reproduce. In this process, one parent cell divides into two parts. Each new cell can then grow to the size of the original parent cell. This is an asexual form of reproduction, so the cells produced are genetically identical. Binary fission can happen very fast. In the time it takes one bacterial cell to divide, the number of cells in the culture doubles. That time is called the doubling time. Escherichia coli cells often divide every...

genomic dna in eukaryotes

How Eukaryotic DNA Fits Inside the Nucleus

Eukaryotic DNA fits inside the nucleus by packing into a highly compact form. Eukaryotes have large genomes compared with prokaryotes, so their DNA must be tightly organized to fit inside one cell. The process starts when DNA wraps around proteins called histones. These DNA-histone units form nucleosomes, which are connected by linker DNA. The nucleosomes then coil into chromatin fibers, and additional fibrous proteins compact the chromatin even more. This packed material is called chromatin,...

interphase

Interphase in the Cell Growth Cycle

Interphase is the stage of the cell cycle when a eukaryotic cell grows and copies its DNA before mitosis. In a typical human cell, the full cell cycle takes about 24 hours, and interphase makes up about 95 percent of that time. It is followed by mitosis, also called M, when the cell divides. After mitosis and cytokinesis, cells enter the G1 phase, or gap 1. During G1, cells grow continuously and prepare for DNA replication. They are metabolically active and copy essential organelles and...

mitosis and cytokinesis

Cell Cycle Stages in Mitosis

Cell cycle stages in mitosis show how a eukaryotic cell copies its DNA and then divides into two daughter cells. The cycle is controlled by regulatory systems and by outside signals that affect cell growth and division. In typical human cells, the full cycle takes about 24 hours and includes two major phases. The first is DNA replication during the S phase of interphase. The second is the mitotic, or M, phase, which includes mitosis and cytokinesis. G1 and G2 are the gap stages between these...

positive regulator molecules

Cyclins and CDKs in the Cell Cycle

Cyclins and CDKs help control the cell cycle, the process that produces daughter cells. Cells use internal checkpoints to make sure their size, energy reserves, and DNA are ready before they move forward. At these checkpoints, positive regulators help the cell continue, while negative regulators slow or stop it. The main positive regulators are cyclins and cyclin-dependent kinases, or CDKs. These proteins are found in eukaryotes, from yeast to humans. Cyclins are grouped by the stage they help...

negative regulator molecules

Cell Cycle Stop Signals: p53, p21, and Rb

Cell cycle stop signals help control when a cell can move forward through division. Negative regulators pause or end the cell cycle until the cell meets the right conditions. Three well-studied negative regulators are p53, p21, and retinoblastoma protein, or Rb. Their roles became clear after faulty versions were found in cancer cells that kept replicating uncontrollably. These proteins act mostly at the G1 checkpoint, which comes early in the cell cycle. P53 has a strong effect on whether a...

cancer

Cancer Treatment, Personalization, and Cell Growth

Cancer develops when mutations affect genes that control cell division. Those changes can remove the normal brakes on growth and lead to uncontrolled cell proliferation. Modern science and medicine have improved how cancer is understood and treated, and some patients can now be cured. There is still no single cure for cancer because cancer is not one disease. It is a large group of many diseases. Even when two people have the same mutation in an oncogene or a tumor suppressor gene, their...

key terms and concepts

Learn how the cell cycle is controlled by G1, G2, and M checkpoints, and how checkpoint failure and telomerase activity can contribute to cancer.

Cell Cycle Checkpoints and Cancer | JoVE K12

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Pennsylvania State Academic Standards

Life Science

Inheritance and Variation of Traits

3.1.9-12.Q

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HIgh School

BIO.3

BIO.3.c

LS.2

LS.2.d

Next Generation Science Standards

High School

From Molecules to Organisms: Structures and Processes

HS-LS1-4

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BIO.6

BIO.6.A

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HS-LS1-4.

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Cell Cycle Checkpoints and Cancer

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