Natural selection was Darwin’s brilliant hypothesis, that accounts for adaptations, features that appear “designed” to fit organisms to their environment.

TLS Online TPP Program

#Id: 10019

#XL - T Zoology

Hh binds to Ptc, causing Ptc to be endocytosed from the cell surface and degraded, relieving the inhibition of Smo.

TLS Online TPP Program

#Id: 8411

#XL - Q Biochemistry

In the absence of Ca2+, muscle is relaxed

TM blocks myosin’s interaction with F-actin

TLS Online TPP Program

#Id: 9970

#XL - T Zoology

In the absence of Wnts,

“free” β-catenin are targeted for degradation by a cytosolic destruction complex that is held together by the tumor suppressor protein Axin.

TLS Online TPP Program

#Id: 9462

#XL - T Zoology

All STAT proteins contain: 

an N-terminal DNA-binding domain

an SH2 domain

a C-terminal domain with a critical tyrosine residue

TLS Online TPP Program

#Id: 8534

#XL - Q Biochemistry

γ-tubulin ring complex (γ-TuRC)

nucleates assembly of a microtubule by forming a template corresponding to the (−) end.