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Describe the role of checkpoints in the onset of cancer?
Cell cycle checkpoints are used by the cell to monitor and regulate the progress of the cell cycle. Checkpoints prevent cell cycle progression at specific points, allowing verification of necessary phase processes and repair of DNA damage. The cell cannot proceed to the next phase until checkpoint requirements have been met. Several checkpoints are designed to ensure that damaged or incomplete DNA is not passed on to daughter cells. Two main checkpoints exist: the G1/S checkpoint and the G2/M checkpoint. G1/S transition is a rate-limiting step in the cell cycle and is also known as restriction point. An alternative model of the cell cycle response to DNA damage has also been proposed, known as the postreplication checkpoint. p53 plays an important role in triggering the control mechanisms at both G1/S and G2/M checkpoints. Impaired spindle checkpoint function has been found in many forms of cancer. The BRCA1 tumor suppressor plays a role in the activation of human chk1, therefore the posreplication checkpoint may prevent the genetic changes that lead to cancer. Mutations in factors contributing to cell cycle arrest at the restriction point are thought to be the main contributors of cancer. hope this helps!
Which stage of cell cycle varies most in length?
There isn't a way (yet) to defined the lengths of stages in the cell cycle. One reason is because the cell cycle makes several stops/checkpoints. The G2 stage has a checkpoint/stop if DNA has not finished replicating and this will prevent the start of the M stage before completion of the S stage. Another cell cycle checkpoint occurs during the M (mitotic) stage. The cell cycle stops if the chromosomes are not going to be distributed correctly to the daughter cells. Damage to the DNA can also stop the cell cycle at the G1 stage and if damage is found then DNA repairs will start but if any kind of problem is not possible to fix than cell will automatically begin apoptosis "a.k.a. cell suicide". For adult mammalian cells, interphase "which includes three stages G1, S, and G2" lasts for about 20 hours and accounts for 90% of the cell cycle and yet embryonic cells can complete the entire cell cycle in just a few hours..
What stage of the cell cycle is a cell's DNA copied?
The stage in the cell cycle where DNA is replicated is actually in interphase, before the nuclear membrane dissolves in prophase. * The DNA is replicated at mid-interphase (in the S phase), between the two growth phases (G1 and G2). So replication precedes division by several hours in a typical cell.
How many cells are at the end of the cell cycle?
one, then it makes two, then those two make more, and so on.
What phase of mitosis are mitochondria made?
It all depends on which organism you are talking about and there is no set phase.In many single-celled eukaryotes, their growth and division is linked to the cell cycle.In single cell algae. the only chloroplast and then the only mitochondrion divide before the nucleus undergoes mitosis and before cytokinesis.In other eukaryotes (in mammals for example), mitochondria may replicate their DNA and divide mainly in response to the energy needs of the cell, rather than in phase with the cell cycle. If it does replicate with the cell cycle, it can occur during the S phase of the mitotic cycle and even through out the mitotic cycle.It all depends on which organism you are talking about and there is no set phase.In many single-celled eukaryotes, their growth and division is linked to the cell cycle.In single cell algae. the only chloroplast and then the only mitochondrion divide before the nucleus undergoes mitosis and before cytokinesis.In other eukaryotes (in mammals for example), mitochondria may replicate their DNA and divide mainly in response to the energy needs of the cell, rather than in phase with the cell cycle. If it does replicate with the cell cycle, it can occur during the S phase of the mitotic cycle and even through out the mitotic cycle.
What happens during the a stage of the cell cycle?
Synthesis of DNA and many other cell organells take place during S-phase of cell cycle.
Describe the role of checkpoints in the onset of cancer?
Cell cycle checkpoints are used by the cell to monitor and regulate the progress of the cell cycle. Checkpoints prevent cell cycle progression at specific points, allowing verification of necessary phase processes and repair of DNA damage. The cell cannot proceed to the next phase until checkpoint requirements have been met. Several checkpoints are designed to ensure that damaged or incomplete DNA is not passed on to daughter cells. Two main checkpoints exist: the G1/S checkpoint and the G2/M checkpoint. G1/S transition is a rate-limiting step in the cell cycle and is also known as restriction point. An alternative model of the cell cycle response to DNA damage has also been proposed, known as the postreplication checkpoint. p53 plays an important role in triggering the control mechanisms at both G1/S and G2/M checkpoints. Impaired spindle checkpoint function has been found in many forms of cancer. The BRCA1 tumor suppressor plays a role in the activation of human chk1, therefore the posreplication checkpoint may prevent the genetic changes that lead to cancer. Mutations in factors contributing to cell cycle arrest at the restriction point are thought to be the main contributors of cancer. hope this helps!
How many chromosomes does a parent cell have?
a parent cell is just one cell. during the cell cycle (mitosis) that cell splits in two
If a cell has six chromosomes at the begginnig of its cell cycle how many chromatids will line up at the equator of the cell during mitosis?
twice as many as when the cell is not undergoing mitosis
How many daughter cells will be created during a single cell cycle?
a gazilloin .......................... i think. kidding im not that stupid
How many checkpoints are there in the Northern route and the Southern route?
There are 26 checkpoints in the Northern route and 29 checkpoints in the Southern route!
How many checkpoints are on this year's race?
There are approximately 396 checkpoints and they each have 3 unicorns.
What is the overall goal of the cell cycle?
An important function of many checkpoints is to assess DNA damage, which is detected by sensor mechanisms. When damage is found, the checkpoint uses a signal mechanism either to stall the cell cycle until repairs are made or, if repairs cannot be made, to target the cell for destruction via apoptosis (effectormechanism). All the checkpoints that assess DNA damage appear to utilize the same sensor-signal-effector mechanism.The cell cycle, according to Temple and Raff (1986),[ 1] was expected to function as a clock; but, if this were the case, it would be expected that the stages of the cell cycle must function according to some sort of internal clock, which would determine how long a phase should last. However, the cell cycle is now depicted as falling dominoes: The preceding phase has to "fall" before the next phase can begin. The cell cycle checkpoints are, therefore, made up of composites of protein kinases and adaptor proteinsthat all play salient roles in the maintenance of the cell division's integrity.The DNA damage checkpoint is always active. Nonetheless, most human cells, for example, are terminally differentiated and must exit the cell cycle. There is a phase late in G1 phase called the restriction point (RP, or the restriction checkpoint); cells that should cease division exit the cell cycle and enter G0. Cells that continually divide in the adult human include hematopoietic stem cells and gut epithelial cells. Therefore, the re-entrant into the cell cycle is possible only by overcoming the RP. This is achieved by growth factor-induced expression of cyclin D proteins. These then overcome the G0 barrier and are able to enter the cell cycle.
How many cells result from the cell cycle?
When a cell undergoes mitosis as part of the cell cycle, it will produce two genetically identical daughter cells.
What is happens during the s phase of the cell cycle?
DNA is replicated.
How many mandatory stop must a musher take during the race?
Well he has to take at least 27, because of the checkpoints, but after that,as many as he wants.
Which stage of cell cycle varies most in length?
There isn't a way (yet) to defined the lengths of stages in the cell cycle. One reason is because the cell cycle makes several stops/checkpoints. The G2 stage has a checkpoint/stop if DNA has not finished replicating and this will prevent the start of the M stage before completion of the S stage. Another cell cycle checkpoint occurs during the M (mitotic) stage. The cell cycle stops if the chromosomes are not going to be distributed correctly to the daughter cells. Damage to the DNA can also stop the cell cycle at the G1 stage and if damage is found then DNA repairs will start but if any kind of problem is not possible to fix than cell will automatically begin apoptosis "a.k.a. cell suicide". For adult mammalian cells, interphase "which includes three stages G1, S, and G2" lasts for about 20 hours and accounts for 90% of the cell cycle and yet embryonic cells can complete the entire cell cycle in just a few hours..
