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

Define nucleosomes , The initial stage of packaging have the binding of t...

The initial stage of packaging have the binding of the chromosomal DNA to histones.  Whole, in chromosomes the ratio of the DNA to histones on a weight basis is around 1:1. There a

Explain what is inversion, Explain what is Inversion ? Inversion is ano...

Explain what is Inversion ? Inversion is another way in which genetic recombination can occur, as seen below. In this case, the change occurs within a chromosome, rather than b

Explain an overview of water soluble vitamins, Explain An Overview of Wate...

Explain An Overview of Water Soluble Vitamins? Vitamins, we already know, are classified by the materials in which they will dissolve. Fat-soluble vitamins -vitamin A, D, E a

Explain antigens, Explain Antigens ? A blood type, or group, is based ...

Explain Antigens ? A blood type, or group, is based upon the presence or absence of certain substances called antigens on the surface of the red blood cells. Antigens are subs

Define procedure for detection of chalk in flour, Define Procedure for Dete...

Define Procedure for Detection of Chalk in Flour Carry out the experiment following the procedure given herewith: 1. Take a teaspoon of flour in a test tube and shake it wit

Nephridia of worms, Normal 0 false false false EN-IN ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Coxal glands, Coxal Glands There is a pair of coxal glands, in almost ...

Coxal Glands There is a pair of coxal glands, in almost all the segments in Onychophora (Peripatus). Developmentally; in every segment a hollow follicle or somite arises and i

Mode of nutrition, illustrate the mode of nutrition in parrot

illustrate the mode of nutrition in parrot

Explain some physiological changes during pregnancy, Explain some Physiolog...

Explain some Physiological Changes during Pregnancy? A whole new life begins at conception. Organ systems develop rapidly and nutrition plays many supportive roles. Pregnancy f

Three main types of trophic pyramids studied in ecology, What are the three...

What are the three main types of trophic pyramids studied in Ecology? The three kinds of trophic pyramids studied in Ecology are the numeric pyramid, the biomass pyramid and th

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