Chapter 21: Development
Which of these is a signal molecule? C B D E A
A
Which of these is a receptor molecule? B A C D E
B
________ aid in the coordination of the activities of adjacent animal cells. Desmosomes Gap (communicating) junctions Keratin fibers Tight junctions Plasmodesmata
Gap (communicating) junctions
A signal molecule is also known as a(n) _____. initiator protein key ligand receptor
ligand
A signal transduction pathway is initiated when a _____ binds to a receptor. G protein cyclic AMP signal molecule calmodulin tyrosine kinase
signal molecule
Which of these cell junctions form a barrier to the passage of materials? keratin fibers tight junctions desmosomes (anchoring junctions) plasmodesmata gap (communicating) junctions
tight junctions Tight junctions form a barrier that prevents fluids from moving between cells.
Which of these is the second of the three stages of cell signaling? gene activation reception binding of a neurotransmitter to a plasma membrane receptor transduction cell response
transduction