Chapter 11 Cell communication

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

What is a G protein?

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

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

• cAMP
• G Protein
• protein kinase
• protein phosphatase

What do second messengers do?

• transport a signal through the lipid bilayer

• relay a signal from the outside to the inside of the cell

• relay message from the inside of the membrane throughout the cytoplasm

• dampen the message

What is a function of the second messenger IP3?

• bind to and activate protein kinase A
• activate transcription factors
• convert ATP to cAMP
• bind to and open ligand-gated channels

Signal amplification is most often achieved by

• an enzyme phosphorylation cascade

• binding of multiple signals

• branching pathways

• action of adenylyl cyclase

What does a protein kinase do?

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

What does a protein phosphatase do?

• removes phosphates
• transfers phosphates from ATP to proteins
• activates an enzyme with a signal molecule

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