Epidermis ;

Consist of single layered, tightly placed, thin walled, uncutinised cells called as Epiblema or Rhizodermis.

Epiblema in younger roots bears Unicellular root hairs and is also called Pilliferous layer

TLS Online TPP Program

#Id: 8856

#XL - T Zoology

Smc1 and Smc3 are members of the structural

maintenance of chromosomes (SMC) protein family, characterized by globular domains at the N- & C-termini connected by a long α helix, bind and hydrolyze ATP.

TLS Online TPP Program

#Id: 8857

#XL - T Zoology

The ATPase domains interact with the proteins

Scc1 and Scc3, which together form a cohesin ring structure which embrace one or both copies of the replicated DNA.

TLS Online TPP Program

#Id: 8858

#XL - T Zoology

Cohesin-mediated cohesion between sister chromatids is established by a two-step process:

1.Loading and unloading of cohesins

2. Stabilization of cohesins

TLS Online TPP Program

#Id: 8859

#XL - T Zoology

During G1, 

cohesins associate with chromosomes by cohesin loading factors Scc2 and Scc4 and unloaded continuously by a cohesin associated complex Pds5 and Wap1 proteins. 

TLS Online TPP Program

#Id: 8860

#XL - T Zoology

During S phase

DNA-bound G1 cohesins Convert into cohesive complexes by cohesin acetyl transferases (CoATs)

which acetylate Smc3 subunit & prevents unloading of cohesins by Pds5-Wapl, thereby stabilizing the cohesins on chromosomes.

TLS Online TPP Program

#Id: 8862

#XL - T Zoology

In vertebrates, stabilization of cohesins requires the cohesin-associated factor sororin.