Question
Question: Why do some hormones (first messenger) need to trigger a “second messenger” to activate a target cel...
Why do some hormones (first messenger) need to trigger a “second messenger” to activate a target cell?
A
The first messenger needs activation of ATP
B
The first messenger cannot cross a plasma membrane
C
There are no specific cell surface receptors for first messenger
D
The first messenger is not a water-soluble molecule
Answer
The first messenger cannot cross a plasma membrane