Carolus Linnaeus - Classified “related” species into genera, “related” genera into orders, and so on. 

To him, “relatedness” meant propinquity in the Creator’s design.

TLS Online TPP Program

#Id: 10005

#Unit 4. Cell Communication and Cell Signaling

Sonic hedgehog is responsible for assuring that motor neurons come only from the ventral portion of the neural tube & essential for normal patterning of the limbs

TLS Online TPP Program

#Id: 10006

#Unit 4. Cell Communication and Cell Signaling

Hedgehog protein with autoproteolytic activity that cleaves off the C-terminus to reveal a signal sequence that marks the protein for secretion.

TLS Online TPP Program

#Id: 10007

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 10008

#Unit 4. Cell Communication and Cell Signaling

The freed C-terminal is not involved in signaling and is often degraded, whereas the N-terminal becomes the active Hedgehog protein intended for secretion

TLS Online TPP Program

#Id: 10009

#Unit 4. Cell Communication and Cell Signaling

Secretion requires the addition of cholesterol and palmitic acid to the Hedgehog protein

TLS Online TPP Program

#Id: 10010

#Unit 4. Cell Communication and Cell Signaling

Two membrane proteins, 

Smoothened (Smo) 

Patched (Ptc)