Cell Signalling and Transduction
Two key organizing principles for large multicellular organisms are

simple nerve reflexes and cell specialization
prokaryotic cell structure and cell specialization
cell specialization and communication between cells
communication between cells and simple nerve reflexes

ANSWER DOWNLOAD EXAMIANS APP

Cell Signalling and Transduction
The signaling molecules called steroid hormones

are made in one location of the body but have their effects some distance away
never enter the blood of humans
bind to cell surface receptors to trigger chemical cascades
are hydrophilic and so cannot penetrate the plasma membrane

ANSWER DOWNLOAD EXAMIANS APP

Cell Signalling and Transduction
A signal cascade induced by adrenaline or thyroxine

All of these
results in the activation of a sequence of enzymes needed for the cell effect
must begin with receipt of the signal molecule by a surface receptor
involves the activation of a G protein

ANSWER DOWNLOAD EXAMIANS APP

Cell Signalling and Transduction
In terms of cell communication, what do bacterial pathogens such as cholera and anthrax have in common?

They block the normal functioning of signal transduction mechanisms
They alter the chemical structure of key signaling molecules
They prevent the production of key signaling molecules
They destroy the receptors for key signaling molecules

ANSWER DOWNLOAD EXAMIANS APP

Cell Signalling and Transduction
Which of the following is true about a hydrophilic signaling molecule?

It might trigger a signal cascade that causes some effect in a cell
Its receptor is located in the cytosol of the target cell
Since it can enter the cell, it directly affects some specific cell process
It is a steroid

ANSWER DOWNLOAD EXAMIANS APP