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

Bohr effect, Bohr Effect Another important influence is the pH. Increa...

Bohr Effect Another important influence is the pH. Increase in carbon dioxide or other acids lowers the pH of plasma and shifts the dissociation curve to the right. At high ca

What is the genotypical proportion of the gametes, Which is the type of gam...

Which is the type of gamete (for a given trait) produced by a dominant homozygous individual? What is the genotypical proportion of these gametes? What about a recessive homozygous

O-linked oligosaccharides , Most proteins made by ribosomes on the RER (rou...

Most proteins made by ribosomes on the RER (rough endoplasmic reticulum) are glycoproteins, which is they hold short chains of carbohydrates (oligosaccharides) covalently related t

How green leaves make food for plants, Green leaves make food for plants ...

Green leaves make food for plants Heat some alcohol in a jar over boiling water unless it boils. Break various green leaves from a geranium or other plant which has been in the

Male reproductive disorders due to infections, Male reproductive disorders ...

Male reproductive disorders due to infections Septicemic infections have a greater affinity for vesicular glands than other regions of the reproductive tract viz. prostate, am

How many cells are in the average human brain, How many cells are in the av...

How many cells are in the average human brain? Roughly, 6 trillion are in the average human brain.

Define paediatric problems and nutritional management, Define Paediatric Pr...

Define Paediatric Problems and Nutritional Management? The process of accepting and digesting food in adequate amounts to meet nutrition needs is termed as feeding. Certain gro

What is the acrosome of the sperm cell, Q. What is the acrosome of the sper...

Q. What is the acrosome of the sperm cell? How is it formed? The acrosome is a structure that contains a great number of digestive enzymes it is formed by the union of Golgi ap

What is anti-arrhythmic pacemaker defibrillators, What is Anti-arrhythmic p...

What is Anti-arrhythmic pacemaker defibrillators ? Antiarrhythmic drugs (AADs) are classified according to whether they exert blocking actions predominantly on sodium, potassiu

Pharmacological treatment, Diuretic Therapy One of the aims of treatment...

Diuretic Therapy One of the aims of treatment of congestive heart failure is directed toward controlling salt and water retention (central or peripheral edema). Diuretics provid

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