Cell Cycle Checkpoints: Mechanisms and Regulation, Schemes and Mind Maps of Physiology

Download Cell Cycle Checkpoints: Mechanisms and Regulation and more Schemes and Mind Maps Physiology in PDF only on Docsity!

Cell Cycle Regulation

The goal of each cell division is to generate two daughterll^ f id^ ti^ l^ ti^

k cells of identical genetic makeup.

High accuracy and fidelity are required to ensure thatDNA replication is carried out correctly and that eachDNA replication is carried out correctly and that eachdaughter^ cell^ inherits^ the

correct^ amount^ of^ genetic material

The^ loss^ of^ normal^ controls

on^ cell^ division^ is^ the f^ d^ t l d f^ t ifundamental defect in cancer

2. S: synthesis phase, the period in which cellsactively replicate their chromosomes.

3. G2: several additional biochemical events necessaryf^ ll di i i^ t k^ lfor cell division take place 4 M: mitotic phase^ which is the division phase4. M: mitotic phase, which is the division phase.

Cell Cycle – RegulationNobel Prize in Physiology or Medicine in 2001 for theinitial experiments that elucidated the masterl f^ ll di i i^ i^ kregulators of cell division in eukaryotes.

Cell^ division^ is^ controlled^

by^ checkpoint^ pathways^ that prevent^ initiation^ of^ each

step^ in^ cell^ division^ until prevent^ initiation^ of^ each

step^ in^ cell^ division^ until earlier steps on which it depends have been completedand^ mistakes^ that^ occurred

during^ the^ process^ have and^ mistakes^ that^ occurred

during^ the^ process^ have been corrected.

Cell cycle checkpointsThe coordination between different phases of the cellcycle is dependent on a series of cell cycle checkpointsy p y^

p that prevent entry into the next phase of the cell cycleuntil the events of the preceding phase have beenl t dcompleted.^ A checkpoint is a stage inthe cell cycle at which thell^ i^ i^ l^ dcell examines internal andexternal signals and decideswhether or not to movewhether or not to moveforward with division.

There cell cycle checkpoints are divided in to twoThere cell cycle checkpoints are divided in to two categories:DNA damage checkpoints andg^ p Spindle assembly checkpoint

DNA damage checkpoints function in G1, S, and G2phases of the cell cycle and named as G1checkpoint, G2 checkpoint and S-phase checkpoint

1.^ G1^ checkpoint:^ arrest

at^ the^ G1checkpoint^ allowsi f DNA d k^ l^ b f^ h^

ll repair of any DNA damage to take place before the cellenters^ S^ phase,^ where^

the^ damaged^ DNA^ would

be replicatedreplicated.^ at the G1/S transitionat the G1/S transition

2. S-phase checkpoint:at S phase The S-phase checkpoint;^ •^ provides continual monitoring of the integrity

of DNA to ensure that damaged DNA is repairedg

p before it is replicated,id^ lit^ t^ l^

it^ t^ t^ th

-^ provides a quality control

monitor^ to promote^ therepair of any errors that occur during DNAreplication such as the incorporation of incorrectreplication, such as the incorporation of incorrectbases or incomplete replication of DNA segments