Control of the cell cycle, Biology

Assignment Help:

The cell cycle is controlled by a cyclically operating set of reaction sequences that both trigger and coordinate key events in the cell cycle

• The cell-cycle control system is driven by a built-in clock that can be adjusted by external stimuli (chemical message).

• Checkpoint - a critical control point in the cell cycle where stop and go-ahead signals can regulate the cell cycle
o Animal cells have built-in stop signals that halt the cell cycles and checkpoints until overridden by go-ahead signals.
o Three Major checkpoints are found in the G1, G2, and M phases of the cell cycle.

• The G1 checkpoint - the Restriction Point
o The G1 checkpoint ensures that the cell is large enough to divide, and that enough nutrients are available to support the resulting daughter cells.
o If a cell receives a go-ahead signal at the G1 checkpoint, it will usually continue with the cell cycle
o If the cell does not receive the go-ahead signal, it will exit the cell cycle and switch to a non-dividing state called G0
o Actually, most cells in the human body are in the G0 phase.

• The G2 checkpoint ensures that DNA replication in S phase has been completed successfully.
• The metaphase checkpoint ensures that all of the chromosomes are attached to the mitotic spindle by a kinetochore. 


Related Discussions:- Control of the cell cycle

Vertebrates, characterstics and classification of vertebrates

characterstics and classification of vertebrates

Abdomen - hypertension, The purpose of examining the abdomen should be for ...

The purpose of examining the abdomen should be for detection of renal artery bruit and abnormal kidney masses like kidney tumours and polycystic kidneys. Aortic abdominal aneurysms

Lungs, what''s the role of lungs in terms of excretion? Like the trachea wh...

what''s the role of lungs in terms of excretion? Like the trachea what''s its role in excretory system?

What are the parathyroids, What are the parathyroids? Where are they locate...

What are the parathyroids? Where are they located and what are the hormones secreted by these glands? The parathyroids are four small glands embedded two in every posterior fac

Properties of transparency factors in corneal hydration, What are special p...

What are special properties of transparency factors in corneal hydration of cornea? The factors affecting the transparency include special properties of the corneal epitheliu

Animals of the littoral zone, Animals of the littoral zone Animals of...

Animals of the littoral zone Animals of this zone may be herbivores, carnivores or detritus feeders and are as diverse as plants. Many of them such as rotifers, protozoans, i

List out the different preservation techniques, List out the Different Pres...

List out the Different Preservation Techniques? The different preservation techniques commonly used today are given in the Table. Table: Methods of food preservation a)

White flowers is crossed with a dwarf plant, a) What new combinations of ch...

a) What new combinations of characteristics might arise in the offspring when a tall plant with white flowers is crossed with a dwarf plant (of the similar species) with red flower

Briefly explain about gelation, Explain Gelation Gelation, which occurs...

Explain Gelation Gelation, which occurs when yolk is frozen and thawed, is apparently due to the aggregation of yolk lipoproteins because  of the imbalance and shift in water.

Explain the physiology of lactation, Explain the Physiology of Lactation? ...

Explain the Physiology of Lactation? Lactogenesis is the onset of copious milk secretion around parturition, triggered by a fall in plasma progesterone levels. Although some co

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd