Signal transduction

The three stages of cell signalling are

• paracrine, local, and synaptic
• reception, transduction, and response
• transcription, translation, and folding
• alpha, beta, and gamma

1.  Each of the following numbered processes are involved in signal transduction pathways:  
 I.  Response  
II.  Amplification  
 III.  Reception  
IV.  Transduction
Which of the following represents the sequence of events in a typical signal transduction pathway?

• I, II, III, IV
• III, I, IV, II
• II, IV, I, III
• III, IV, II, I

A signal molecule that binds to a plasma-membrane protein is a

• ligand
• second messenger
• protein kinase
• receptor protein

What determines whether a signal molecule binds on the surface or enters the cell?

• size
• polarity
• ability to cross the membrane
• all of these are correct

What type of transmembrane receptor is being shown?

• G-protein receptor
• tyrosine kinase receptor
• gated ion channel

Protein kinases activate other relay proteins by adding a(n) ____ to them.

• phosphate
• ATP molecule
• cAMP
• GTP

Adenylyl cyclase is used in a G-protein pathway to 

• cause ATP to form cAMP
• add a phosphate to a kinase
• remove a phosphate from a kinase
• attract a ligand

cAMP and calcium are examples of 

• secondary messengers
• hormones
• ligands
• enzymes

What type of transmembrane receptor is being shown?

• gated ion channel
• G-protein receptor
• tyrosine kinase receptor

Consider this pathway: epinephrine --> receptor --> cAMP --> protein kinase --> transcription factors. 

Identify the secondary messenger.

• epinephrine
• G protein-coupled receptor
• adenylyl cyclase
• cAMP