Cell Signaling

In paracrine signaling, the signaling molecules affects only

• target cells close to the cell from which it was secreted
• target cells distant from its site of synthesis in cells of an endocrine organ
• both (a) and (b)
• none of the above

What is the name of the signaling molecule that triggers a transduction pathway?

• ligand
• GTP
• kinase
• phosphatase

What is the name of the pathway that occurs when a signal is received and then converted into a cellular response?

• signal transduction
• biochemical
• catabolic
• anabolic

What is the name of the molecule that is used in long distance signaling; travels from one gland to another location to trigger the signal?

• hormone
• neurotransmitter
• ion

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

Kinases are de-activated when 

• phosphate is removed by a phosphatase
• GTP attaches to them
• ligand is released from the receptor
• apoptosis occurs

Which of these means "signaling by touching another cell?"

• Juxtacrine
• paracrine
• Endocrine
• exocrine

Which of these means "signaling from close distances?"

• Paracrine
• Endocrine
• Exocrine
• Juxtacrine

G proteins are a family of proteins involved in some types of cell cell signaling. G proteins function as molecular switches.
Which of the following best describes the role in which a G protein is most directly involved?

• Production of the ligand molecule.
• Reception of the signal.
• Transduction of the signal.
• Production of response to signal.