Respuesta :
AIII
Explanation:
- Cell cycle is mainly divided into two phases-Interphase and Mitotic phase
- Interphase is the preparatory phase whereas mitotic phase is the dividing phase
- Various cyclins and Cdks are regulated during these phases
- M-Cdks stands for Mitotic Cyclin Dependent Kinases which helps in cell cycle regulation
- Cdks are the catalytic subunit bound to the regulatory subunit(cyclins)
- Mitosis includes four stage namely Prophase,Metaphase,Anaphase and Telophase
- During the Anaphase stage separation of sister chromatids occurs due to the destruction of a protein called cohesin
- Destruction of cohesin is catalysed by an enzyme called separase
- Prior to anaphase securin binds to separase and inhibits its activity
- The APC(anaphase promoting complex) with specificity factor Cdc20 tragets securin for polyubiquitination which then degraded by proteasome
- The separase released becomes active and breaks the bridge between sister chromatids
- Movement of sister chromatids occurs towards their respective poles
- In late anaphase,specific phopshates called Cdc14 removes the regulatory phosphate group from cdh1 specificity factor and therefore Cdh1 becomes active
- Active Cdh1 specificity factor binds to and activate APC(anaphase promoting complex)
- Cdh1 bound APC catalyse ubiquitination of mitotic cyclins
- As the mitotic cyclins are degraded by the proteasome,onset of telophase starts
- Wee1 is a kinase enzyme which comes into consideration in case of fission yeast
- Wee 1 phosphorylates the inhibitory site of M-Cdk which further leads the cells to enter into mitosis
