BIOL 252 Human Anatomy & Physiology II w/Lab Module 1 Latest Exam with Frequently Asked Questions and Verified Answers

BIOL 252 Human Anatomy & Physiology II w/Lab Module 1 Latest Exam with Frequently Asked Questions and Verified Answers A researcher observes that a hormone released into the bloodstream affects only cells containing a specific receptor protein. Which principle of chemical communication does this demonstrate? A. Hormonal signals affect all cells equally B. Target cells respond only if they possess the appropriate receptor C. Hormones act only through direct cell-to-cell contact D. Receptors are unnecessary for hormone action Correct Answer: B. Target cells respond only if they possess the appropriate receptor Rationale: Chemical communication depends on specificity between a signaling molecule and its receptor. Only cells with the correct receptor can detect and respond to a particular hormone. ________________________________________ Which type of chemical messenger is released by neurons and travels across a synaptic cleft to communicate with another cell? A. Hormone B. Neurotransmitter C. Enzyme D. Electrolyte Correct Answer: B. Neurotransmitter Rationale: Neurotransmitters are chemical messengers released from neurons that diffuse across synapses to transmit signals to other neurons, muscles, or glands. ________________________________________ A hormone binds to a receptor located on the plasma membrane of a target cell. Which class of hormone most commonly uses this signaling mechanism? A. Steroid hormones B. Thyroid hormones C. Water-soluble hormones D. Cholesterol molecules Correct Answer: C. Water-soluble hormones Rationale: Water-soluble hormones, such as peptide and many amino acid-derived hormones, cannot easily cross the lipid membrane and therefore bind to receptors on the cell surface.