“MEMPOT”© – Computer Simulation of Membrane Potential Measurements INTRODUCTION “MEMPOT”© is an interactive graphical simulation program that is designed to show how cell membrane potentials are measured with microelectrodes in the laboratory situation. The simulation shows how the membrane potential depends on the external potassium‚ [K+]o and external sodium‚ [Na+]o concentrations and the relative permeability of the membrane to these ions. The program simulates membrane potential measurements in any
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why increasing extracellular K+ causes the membrane potential to change to a less negative value. How well did the results compare with your prediction? Your answer: If extracellular K+ is increased then the intracellular K+ will decrease. Fewer intracellular K+ ions would result in the membrane potential being less negative. This is what I predicted to happen. 3. Explain why a change in extracellular Na+ did not significantly alter the membrane potential in the resting neuron? Your answer:
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dendrite -> soma -> axon -> synapse Lecture 2 – Chapters 4 & 5 Ion channels and signalling - ions are separated by cell membrane; when ion channels are opened‚ ions flow -> generating electrical signals -> so neurons can communicate info through these electrical signals - neurons generate a constant negative voltage across membrane: the rmp - an AP abolishes the –ve rmp‚ making membrane potential transiently positive - we can record and measure ion currents using electrophysiology - hyperpolarization
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The next two questions refer to the diagrams below representing an organelle from a cell. Question3: The organelle in the diagram is: a) The nucleus of a cell b) A Mitochondria c) Part of the cell membrane d) A golgi body Question 4: The function of this organelle is to: a) Control the metabolism of the cell b) Modify proteins by adding a glycoprotein c) Synthesis proteins d) Package molecules into vesicles before secreting them from
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Title: Colligative Properties & Osmotic Pressure Background: Important terms to study from this lab assignment are colligative properties‚ membrane permeability and osmotic pressure. First‚ colligative properties are “those of a solution that depend solely on the number of solute particles present‚ not the identity of those solute particles. These properties include: vapor pressure lowering‚ boiling point elevation‚ freezing point depression‚ and osmotic pressure” (p. 17 lab manual). In this experiment
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Exercise 3: Neurophysiology of Nerve Impulses: Activity 1: The Resting Membrane Potential Lab Report Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. 1. What is the approximate concentration of K+ inside a typical cell (intracellular concentration)? You correctly answered: a. 150 mM 2. What is the approximate concentration of K+ outside a cell (extracellular concentration)? You correctly answered: b. 5 mM 3. What is the approximate concentration of Na+ inside
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down to the axon terminal of the presynaptic neuron. Each axon terminal becomes swollen forming a presynaptic knob. There is a depolarisation of the presynaptic membrane resulting from the action potential. This depolarisation causes an increase in the permeability to sodium and calcium ions. The presynaptic knob is then filled with membrane-bound vesicles; each filled with a neurotransmitter. Calcium ions then flood into the presynaptic knob by diffusion. The influx of calcium ions triggers the exocytosis
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1. a. The action potential changes the membrane potential from -70 mV (resting) to +30 mV and back again to the resting membrane potential. b. This results from a change in membrane permeability first to Na then to K due to the opening of what type of ion channels? Voltage gated channels 2. a. Where is the density of voltage-gated Na+ channels the greatest? Axon hillock b. What areas of the neuron generate signals that open these voltage-gated channels? Dendrites and the cell body c. Opening
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determines the permeability of the sucrose. The sucrose molecules are too large to pass through. Figure 1b- sucrose concentration determines the weight change. In this case based on our results as concentration increases the percent weight change is decreasing. Discussion: The purpose of this lab was to observe and analyze various factors that affect the process of diffusion and osmosis. We observed that the permeability of the dialysis tubes‚ which is our permeable “membrane”‚ depends on the
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fluid-mosaic model of a plasma membrane. Discuss the role of the membrane in the movement of materials through each of the following processes: a.) Active Transport b.) Passive Transport All living cells contain a plasma membrane‚ which acts a boundary for the cell. The plasma membrane regulates the cell’s chemical composition because it uses selective permeability to allow certain substances to enter or exit the cell more easily than others. The formation of this membrane is believed to be one of
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