BIOL 212 Exam Questions And Answers (Verified And Updated)

BIOL 212 Exam Questions And Answers (Verified And Updated) Which ion most readily leaks across a neuron's membrane, helping to establish the resting potential? - answerK+ In resting neurons, the membrane is selectively permeable to K+ through a K+ channel protein. As K+ leaves the cell along its concentration gradient, the inside of the membrane becomes negatively charged relative to the outside. Will K+ continue to leave the cell indefinitely? - answerNo−−as the interior of the cell becomes more negative, the electrical gradient counteracts the movement of K+ out of the cell. Eventually, there is no net movement of K+. The nucleus and most of the organelles in a neuron are located in the _____. - answercell body For a neuron at rest with a membrane potential of -65 mV, an increase in the movement of potassium ions out of that neuron's cytoplasm would result in the ________. - answerhyperpolarization of the neuron. The operation of the sodium-potassium "pump" moves ________. - answersodium ions out of the cell and potassium ions into the cell. The membrane potential in which there is no net movement of the ion across the membrane is called the _____. - answerequilibrium potential ATP hydrolysis directly powers the movement of ________. - answerNa+ out of the cell. Which of the following statements about action potentials is correct? - answerAction potentials are propagated down the length of the axon. The three distinct phases of an action potential occur in what order? - answerdepolarization, repolarization, hyperpolarization The "threshold" potential of a membrane is the _____. - answerminimum depolarization needed to operate the voltage-gated sodium and potassium channels What would probably happen if a long neuron had one continuous myelin sheath down the length of the axon with no nodes of Ranvier? - answerThe signal would fade because it is not renewed by the opening of more sodium channels.