Signal Transduction system

Question 1

List the six features of signal transduction systems

Answer 1

Specificity
Amplification
Modularity
Desensitisation/Adaption
Integration
Localised response

Question 2

Specificity

Answer 2

Signals are specific for each receptor.
Precise complementarity between the signal and receptor binding site.
Some signals/receptors may only be present in some cell types, further increasing specificity.

Question 3

Amplification

Answer 3

Also referred to as enzyme or signal cascade.
Due to a single enzyme activating multiple second enzymes at multiple levels.
Can occur rapidly in a cell.

Question 4

Modularity

Answer 4

Many proteins have multiple domains recognising specific features in other proteins.
Allows cells to mix and match a set of signals to a variety of protein complexes with different functions.
Phosphorylation (and dephosphorylation) of Amino acid residues is often used to regulate binding of signalling components.

Question 5

Desensitisation

Answer 5

When a signal is constantly present, receptor systems become desensitised and no longer respond.
Once the signal drops in concentration below a threshold, the system can become sensitive again.

Question 6

Integration

Answer 6

Signalling systems can combine the input of multiple signals to give a response that reflects both systems.
Many signalling systems communication at multiple levels to maintain homeostasis.

Question 7

Response localisation

Answer 7

When the components of a signalling system are confined to a location, calls can regulate a process locally without affecting other cells.