mastering 11 hmwrk with complete solution 2023

mastering 11 A resting neuron is an unstimulated neuron that is not presently generating an action potential. The resting membrane potential is the separation of the relative positive and negative charges across the membrane of a cell at rest. Drag the charges to the correct side of the membrane to represent the resting membrane potential of a typical neuron. - correct answer The separation of charges creates a voltage (electrical potential difference), which can be measured using a voltmeter. The resting membrane potential of a neuron averages -70mV (millivolts). All neural activities begin with a change in the resting membrane potential of a neuron. The resting membrane potential is dependent upon two important factors: 1) differences in sodium and potassium concentrations across the membrane (electrochemical gradients) and 2) differences in sodium and potassium membrane permeability. This activity will help you to review how the resting membrane potential of cells are generated and maintained. Use the provided ions to correctly complete each sentence about the resting membrane potential. Ions may be used more than once, or not at all. - correct answer All living cells have a membrane potential that varies depending on its cellular activities. Drag and drop the correct concentrations and the direction of the concentration gradient in a cell at RMP. Answers may be used more than once or not at all. The appropriate arrow should be placed on the plasma membrane—the targets appear on either side of the pumps. - correct answer The Na+ concentration is higher outside of the cell, while the concentration of K+ is higher inside the cell. Which choice best characterizes K+ leakage channels? - correct answer transmembrane protein channels that are always open to allow K+ to cross the membrane without the additional input of energy Assume you have a membrane with only potassium leakage channels. The RMP is -90mV. Predict the RMP if we add Na+ leakage channels.The most likely RMP value of Na+ is __________. - correct answer -70 mV Imagine that the cell membrane from the previous problem becomes more permeable to Na+. Predict how this will affect the RMP. - correct answer The RMP will be more positive. Complete the following sentence. The operation of the Na+−K+ ATPase pump __________. - correct answer moves 3 Na+ to the ECF and 2 K+ to the cytoplasm -The pumps move more Na+ than K+, which counteracts the effect of the membrane's being more permeable to K+ (more K+ leak channels than Na+). You are going to record RMP from a cell using an electrode. You place your electrode and record a resting membrane potential every millisecond. You record an initial value of -70mV; however, over time you notice that your recordings become more and more positive until the RMP reaches 0mV. Assuming that Na+ and K+ are the major determinants of RMP in this cell, which of the following could best explain your results? - correct answer The cell's Na+-K+ ATPase pumps have stopped functioning. -Yes! Since the RMP eventually becomes zero, the concentration of ions on either side of the membrane would be roughly equal. Without active processes to maintain concentration gradients, we would expect the concentration of ions on either side of the membrane to equilibrate. Cl− is a common, negatively charged extracellular ion. Predict the effect on the RMP if many Cl− gated channels are suddenly opened - correct answer A more negative RMP would result. -Correct! Cl− is negatively charged and has a higher concentration in the ECF. The opening of Cl− channels would allow more negative charge to attempt to enter the cytoplasm. If the cell's normal RMP were -70mV, it would now become more negative. The farther away the RMP is from zero, either in the positive or in the negative direction, the greater the separation of charges is. This is called hyperpolarization. When the RMP moves closer to 0 mV, depolarization occurs.Congratulations! You've successfully examined the construction of the resting membrane potential, an important concept in any human cell. The small space between the sending neuron and the receiving neuron is the - correct answer Synaptic Cleft -The synaptic cleft is the small space between the sending neuron and the receiving neuron. A molecule that carries information across a synaptic cleft is a - correct answer neurotransmitter -Neurotransmitter molecules carry information across a synaptic cleft. When calcium ions enter the synaptic terminal, - correct answer they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.