Chapter 9 Quiz 1

Which of the following is NOT true about G proteins? Some G proteins are composed of three subunits. G proteins release GDP and bind GTP when associated with an activated receptor. All G proteins are a component of a signal-transduction pathway and associate with a G protein-coupled receptor. G proteins become deactivated when bound GTP is hydrolyzed to GDP

All G proteins are a component of a signal-transduction pathway and associate with a G protein-coupled receptor.

A protein on a cell surface that binds to a signaling molecule is an example of which of the following elements of cellular communication? a signaling molecule a receptor protein a signaling cell None of the other answer options is correct. a responding cell

a receptor protein

Which of the following would NOT be considered a cell-surface receptor? a receptor that causes GDP to be exchanged for GTP in a G protein a receptor that allows ions to enter the cell when a ligand binds a receptor that binds a nonpolar steroid hormone and activates transcription a receptor that must form a dimer after binding the ligand to transmit a signal

a receptor that binds a nonpolar steroid hormone and activates transcription

Which of the following is a type of cell communication where the signaling molecule is released by the same cell that responds to the signal? All of these choices are correct. endocrine autocrine contact-dependent paracrine

autocrine

Which type of receptor is involved in rapid responses of muscle cells and neurons? G protein-coupled receptor receptor kinase ligand-gated ion channel intracellular receptor

ligand-gated ion channel