Cell Signaling

Which of the following would be an example of paracrine signaling in animals?

• neurotransmitter acetylcholine
• hormone epinephrine
• neurotransmitter norepinephrine
• growth factor

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

What is a G protein?

• specific type of membrane-receptor protein
• protein on the cytoplasmic side of a membrane
• membrane-bound enzyme
• relay protein

Signal amplification is most often achieved by

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

Which of the following is involved in many human medicines for disease?

• cAMP
• Calcium concentration
• G-protein pathways
• receptor tyrosine kinases

What does a protein kinase do?

• removes phosphates
• transfers phosphates from ATP to proteins
• activates an enzyme

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

Do plant cells communicate using hormones?

• yes
• no