Cell Communication

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

• ligand
• second messenger
• protein kinase
• receptor protein

Which of the following can activate a protein by transferring a phosphate group to it?

• cAMP
• G Protein
• protein kinase
• protein phosphatase

Signal amplification is most often achieved by

• an enzyme cascade
• binding of multiple signals
• branching pathways
• action of adenylyl cyclase

What is a phosphorylation cascade?

• travelling of hormones through the air
• travelling of hormones through the blood
• the removal of a phosphate
• a series of molecules that get phosphorylated

What determines whether a cell is a target cell for a particular signal molecule?

• phosphorylation cascade
• cAMP
• signal receptors
• phosphatase

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

Which of the following is a chemical message that usually travels through the bloodstream to target cells?

• hormone
• local regulator
• endocrine cell

The 3 steps of signal transduction in order are

• reception, transduction, response
• response, transduction, reception
• reception, response, transduction
• transduction, reception, response

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

• phosphate
• ATP molecule
• cAMP
• GTP

This is an example of

• paracrine signaling
• synaptic signaling
• long-distance signaling
• all of the above