BIO 235 Final Exam Questions With 100% Correct Answers 2024/2025

BIO 235 Final Exam Questions With 100% Correct Answers 2024/2025 Potassium: A. is more abundant outside the cell than inside the cell. B. moves into the cell during an action potential. C. is transported out of the neuron by the sodium-potassium pump. D. leaks out of the cell more than sodium leaks into the cell. - answerc. salutary and continuous action potential conduction - answerconduction occurs in myelinated axons. Nerve signals transmit much faster than in continuous conduction because an action potential is generated only at the neurofibrils (segments of axon without myelination) of myelinated axon rather than along the entire length of unmyelinated axon. EPSP - answerExcitatory postsynaptic potential; a slight depolarization of a postsynaptic cell, bringing the membrane potential of that cell closer to the threshold for an action potential. Spacial and temporal summation - answersummation in axon hillock of post synaptic potentials across the cell body, summation of potentials that reach the axon hillock at different times, closer in time, more complete the summation An action potential reaches the synaptic terminal of a presynaptic cell. How does this message get transmitted to the postsynaptic cell? Please only describe what is happening at the location where this message transfer occurs, but be sure to include all relevant chemicals and parts of the cell involved. - answerWhen an action potential reaches the axon terminal it depolarizes the membrane and opens voltage-gated Na+ channels. Na+ ions enter the cell, further depolarizing the presynaptic membrane In a cross section of the spinal chord the areas that are grey are (a)___________________________ neurons and the areas that are white are called _____________________ neurons - answerThe gray matter is made up of neuroglia cells and neuron cell bodies. The white matter is made up of neuron axons, mostly but not all myelinated. (Using the figure/graph) Which of the following is happening during the period indicated by the number 2 on the graph? A. There is no ion movement during this period. B. chloride is entering the neuron through chemically-gated channels. C. potassium is leaving the neuron through voltage-gated channels. D. sodium is entering the neuron through voltage-gated channels. - answersodium is entering the neuron through voltage-gated channels. A strong stimulus coming into a dendrite of a multipolar neuron will cause a strong graded potential to be generated. True False - answertrue Myelin Sheaths in the PNS: a. Increases speed of action potentials b. Protects and electrically insulates neurons from one another c. All of the answers are correct d. Concentric layers of Schwann cells membrane e. None of the answers are correct - answerAll of the above Where would you find sodium-potassium pumps and leak channels on a neuron? A. cell body only B. synaptic terminal only C. entire neuron cell membrane D. axon only E. dendrites only - answerA. cell body only An IPSP: A. is caused by a chemically-gated sodium channel opening. B. hyperpolarizes the post-synaptic cell pushing it farther from threshold. C. is a graded depolarization of the post-synaptic cell. D. is an excitatory stimulus bringing the neuron closer to an action potential. - answerB. hyperpolarizes the post-synaptic cell pushing it farther from threshold Are the first channels opened when -55mV is reached at the axon hillock. - answerVoltage- gated sodium channels Cause the transmembrane potential to maintain a relatively stable state of -70mV. - answer Cause a graded depolarization to occur on the cell body and dendrites. - answer Cause the transmembrane potential to go from +30mV to about -90 mV. - answer Cause synaptic vesicles to migrate to the cell membrane at the synaptic terminal. - answercalcium produce myelination in the peripheral nervous system (PNS) neurons. A. Schwann cells B. Satellite cells C. Astrocytes Ependymal cells D. Oligodendrocytes E. Microglia - answerSchwann Cells What causes chemically-gated channels to open? A. The binding of calcium ion to the channel. B. The binding of neurotransmitter to the channel. C. The binding of potassium ion to the channel. D. The binding of a sodium ion to the channel. - answerB. binding of a neurotransmitter Because all action potentials are alike, how does a neuron communicate to the next neuron if the original stimulus was intense or just a neusance? - answer Describe what is happening in the neuron during a graded potential. Please only describe what is happening at the location where the graded potential occurs, but be sure to include all relevant chemicals and parts of the cell involved - answeris produced when a ligand opens a ligand- gated channel in the dendrites, allowing ions to enter (or exit) the cell. The graded potential will