Cell Cycle Regulation | Basic Overview

The cell cycle, or cell-division cycle, is the series of events that take place in a cell that cause it to divide into two daughter cells. These events include the duplication of its DNA (DNA replication) and some of its organelles, and subsequently the partitioning of its cytoplasm and other components into two daughter cells in a process called cell division.
In cells with nuclei (eukaryotes), (i.e., animal, plant, fungal, and protist cells), the cell cycle is divided into two main stages: interphase and the mitotic (M) phase (including mitosis and cytokinesis). During interphase, the cell grows, accumulating nutrients needed for mitosis, and replicates its DNA and some of its organelles. During the mitotic phase, the replicated chromosomes, organelles, and cytoplasm separate into two new daughter cells. To ensure the proper replication of cellular components and division, there are control mechanisms known as cell cycle checkpoints after each of the key steps of the cycle that determine if the cell can progress to the next phase.
Two key classes of regulatory molecules, cyclins and cyclin-dependent kinases (CDKs), determine a cell's progress through the cell cycle. Many of the genes encoding cyclins and CDKs are conserved among all eukaryotes, but in general more complex organisms have more elaborate cell cycle control systems that incorporate more individual components. Many of the relevant genes were first identified by studying yeast, The genetic nomenclature in yeast dubs many of these genes cdc (for "cell division cycle") followed by an identifying number, e.g. cdc25 or cdc20.
Cyclins form the regulatory subunits and CDKs the catalytic subunits of an activated heterodimer; cyclins have no catalytic activity and CDKs are inactive in the absence of a partner cyclin. When activated by a bound cyclin, CDKs perform a common biochemical reaction called phosphorylation that activates or inactivates target proteins to orchestrate coordinated entry into the next phase of the cell cycle. Different cyclin-CDK combinations determine the downstream proteins targeted. CDKs are constitutively expressed in cells whereas cyclins are synthesised at specific stages of the cell cycle, in response to various molecular signals.
Upon receiving a pro-mitotic extracellular signal, G1 cyclin-CDK complexes become active to prepare the cell for S phase, promoting the expression of transcription factors that in turn promote the expression of S cyclins and of enzymes required for DNA replication. The G1 cyclin-CDK complexes also promote the degradation of molecules that function as S phase inhibitors by targeting them for ubiquitination. Once a protein has been ubiquitinated, it is targeted for proteolytic degradation by the proteasome. However, results from a recent study of E2F transcriptional dynamics at the single-cell level argue that the role of G1 cyclin-CDK activities, in particular cyclin D-CDK4/6, is to tune the timing rather than the commitment of cell cycle entry

[@snf5724]

Very clear, you did a great job, thanks a lot

[@AmritaPBB]

Hussain Sir, You are like God of Biology...your lectures have so much clarity and depth. Thanks a lot..

[@hussainbiology]

thanks Amrita for appreciation.. It really means a lot for me.... Keep sharing and supporting ✌️✌️

[@dreameducation586]

Sister, You can say best teacher , Please don't use the Word God for a human, I hope Hussains biology will also not like it.

[@juttgaming7658]

Right 👍

[@owoeyepaul8995]

You can say god of biology, because the Bible even confirms we are gods (Psalm 82:6), helped by GOD to know the works of GOD and to replicate it. Of course, the work of GOD on earth is invention and maintenance, and that's what we small gods are to do with full loyalty to GOD first. We must first be saved from sin for HE is a holy God. We are saved through Jesus Christ.

[@X.N.M]

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[@botanywithmalabika5702]

Outstanding explanations!!

[@shwetapandey1194]

You are helping me so much in my studies.. I'm grateful to you.🙏🏻

[@hussainbiology]

thanks Shweta for appreciation..Glad it helps ✌️

[@scibasics_123]

Great 👍 explanation

[@vaishalisingh1301]

Thankyou for easiest way to explain

[@oscarluisvermat7935]

very clear explanation! Thanks!

[@hussainbiology]

thanks for appreciation..Glad it helps....✌️

[@michaeleisenberg7867]

Good Morning 🌄 Shabir, That was packed with fascinating info! 👏👏👏 Somewhere in there the DNA 🧬 polymerases must get turned on and off🎚. Thank you 😊, stay well 💪, and keep up the good work!! 💖💫🏅

[@hussainbiology]

Hi Dr Mike.... Indeed Polymerases are master proteins when we talk about division

[@jyothirmaisunkari6662]

Most watching channel..thanku hussain biology

[@hussainbiology]

thanks for appreciation... Glad u like Hussain Biology

[@sanaullah-fw9jb]

East or west you are the best

[@techrg3218]

Thanks ❤️

[@ginger-lemon]

Fantastic

[@Muzee123]

Sir do make detailed video on this topic . we have to understand it's regulation in detail at mol level 5 minutes are not engh. Any ways thank u.

[@ammaramehak9473]

good work keep it up .

[@hussainbiology]

thanks buddy for appreciation

[@kaisarparray6552]

My oltym fav. 😍

[@shwethakrishna3716]

Thanks sir.. it's amazing

[@hussainbiology]

thanks for appreciation.. Glad to know that it helps ✌️

[@user-bb9xz5ls2z]

Thanks you

[@muhammadpervaiz8347]

Need more and more videos of this topics

[@hussainbiology]

surely

[@blackyrocky7438]

What about the cell cycle regulation from genes.

[@itsnotshi]

saving my life the night of the exam!

[@hussainbiology]

thanks for appreciation..Glad it helps ✌️

[@balanpk719]

Can you make a video on making lizol type disinfectant floor cleaner?

[@monalisapal9238]

What kind of joke is this !!!??

[@manishamathur3941]

sir, please explain A1 Mitosis.

[@curlyhairmessingwithworld]

4:35 apc/c expand it guys I'm confused

[@scibasics_123]

@Sci Basics

[@Mesut-2323]

thanks from Turkey (Türkiye)

[@hussainbiology]

My pleasure.. Keep sharing and supporting ✌️

[@Mesut-2323]

@@tubahussain6541 Yes 👍🤗🤗

[@Mesut-2323]

@@tubahussain6541 yes and watching 2nd time now 👍

[@Mesut-2323]

@@tubahussain6541 not now but in the near future.

[@Mesut-2323]

@@tubahussain6541 🤗👍

[@KhangNguyen-vs2su]

Some segments in the video are stamped not adjacent to each other

[@hussainbiology]

I dont know where , but if it is , does it affect the info ?

[@tanu6464]

😊😊

[@anandruban8348]

May I know Where are these reference are taken ?

[@hussainbiology]

Cell Biology -Alberts Cell Biology- Lodish

[@anandruban8348]

Ok sir thank you

[@sssssanaaa5561]

sir can we get the resume of this lecture? like notes

[@hussainbiology]

just email [e-mail]

[@kaneezezahra9270]

Sir amazing but hindi explanation is also help

[@hussainbiology]

thanks Kaneez... Hindi mai bolta fr toa Sirf Asia k log dekh paate.. Aise toa sab dekh sakte hai....

[@user-hr4jo2eu2b]

Have a good day productions idess and goodnight

[@shabihusain3901]

why so cell cycle so complicated😵

[@renuverma7771]

I want to join

[@renuverma7771]

Want to know all rules. 💰

[@hussainbiology]

It is simple... U join and get what is written on each Tier... Like Level 1 gets Shout out , stickers ... 👍👍 Level 2 gets images of topic etc

[@Vxneji]

in da es Paze