Neurophysiology Ion Channels Past Paper PDF

From Molecule to mind Test 1 - **Neurophysiology Ion channels** **rue/False Questions** 1. Neurons communicate only through electrical signals. F 2. All neurons have a negative resting membrane potential relative to the outside of the cell. T 3. Injecting positive current into a neuron w...

From Molecule to mind Test 1 - **Neurophysiology Ion channels** **rue/False Questions** 1. Neurons communicate only through electrical signals. F 2. All neurons have a negative resting membrane potential relative to the outside of the cell. T 3. Injecting positive current into a neuron will cause hyperpolarization. F 4. Neurotransmitter receptors like glutamate and GABA are examples of voltage-gated ion channels. F 5. Potassium channels open quickly and close faster than sodium channels. F 6. Inactivation gates of sodium channels close to prevent prolonged depolarization. T 7. Tetrodotoxin (TTX) blocks calcium channels in nerve cells. F 8. Ion channel mutations can lead to diseases like cystic fibrosis and migraines. T **Multiple Choice Questions** 1. **What type of ion channel opens in response to a chemical ligand?**\ a) Voltage-gated ion channels\ b**) Neurotransmitter receptor channels**\ c) Mechanosensitive ion channels\ d) Aquaporins 2. **Which of the following is most important for generating action potentials?**\ a) Cl⁻ channels\ **b) Na⁺ and K⁺ channels**\ c) Ca²⁺ channels\ d) Neurotransmitter receptors 3. **Which recording technique measures very small ionic currents by making tight contact with the membrane?**\ a) Whole-cell recording\ **b) Cell-attached recording\ **c) Intracellular recording\ **d) Patch-clamp recording** 4. **What type of ion channel behavior is described as stochastic?**\ a) **Random opening based on voltage**\ b) Channels that always open at the same voltage\ c) Channels that are permanently open\ d) Channels that open due to mechanical stretch 5. **Which ion channels are crucial for maintaining the resting membrane potential?**\ a) Na⁺ channels\ b) K⁺ channels\ **c) Cl⁻ channels**\ d) Ca²⁺ channels 6. **In familial migraines, the mutation in which ion channel leads to abnormal depolarization?**\ a) Sodium channel\ b) Chloride channel\ c) Potassium channel\ **d) Calcium channel** **Open-Ended Questions** 1. Describe the role of ion channels in generating and propagating action potentials. 2. Explain the difference between voltage-gated and neurotransmitter receptor ion channels in terms of their activation and function. 3. How do toxins like tetrodotoxin (TTX) and conotoxin affect ion channel function, and why are they useful in scientific research? 4. What are the key differences between sodium and potassium channels in terms of activation and inactivation? **Matching Questions** Match the ion channel with its function or description. **Ion Channel** **Function/Description** ------------------------------------------ -------------------------------------------------------------- 1\. Na⁺ channels c a\) Important for resting membrane potential 2\. K⁺ channels a b\) Activated by chemical ligands like GABA 3\. Ca²⁺ channels e c\) Crucial for action potential depolarization 4\. Cl⁻ channels a d\) Plays a key role in depolarization 5\. Neurotransmitter receptor channels b e\) Involved in the release of neurotransmitters at synapses Test 2 **Section A: True/False Questions** 1. The resting membrane potential of neurons is typically positive. (TrueFalse) 5. During birth, oxytocin activates chloride pumps, increasing the intracellular concentration of Cl⁻. (True/**False**) **Section B: Multiple Choice Questions** 6. Which of the following best describes the role of the **Na⁺/K⁺ pump** in establishing the resting membrane potential? - A\) It allows free movement of Na⁺ and K⁺ ions across the membrane. - **B) It pumps 3 Na⁺ ions out of the cell and 2 K⁺ ions into the cell, maintaining a negative charge inside.** - C\) It pumps K⁺ ions inside the cell and Na⁺ ions outside, maintaining a positive charge inside. - D\) It requires no energy to move Na⁺ and K⁺ ions. 7. What happens when extracellular **K⁺ concentration increases**? - A\) The membrane hyperpolarizes. - **B) The membrane potential depolarizes**. - C\) There is no effect on membrane potential. - D\) The membrane becomes more negative. 8. Which ion has the largest driving force across the membrane at resting potential due to its low intracellular concentration? - A\) Potassium (K⁺) - B\) Sodium (Na⁺) - C\) Chloride (Cl⁻) - **D) Calcium (Ca²⁺)** 9. During an action potential, when **sodium channels open**, the membrane potential rapidly moves towards: - A\) 0 mV - B\) The equilibrium potential of potassium (-100 mV) - **C) The equilibrium potential of sodium (+60 mV)** - D\) The equilibrium potential of calcium (+120 mV) 10. Which equation is used to calculate the **membrane potential** while considering ion permeability and concentration differences? - A\) Nernst Equation - **B) Goldman-Hodgkin-Katz Equation** - C\) Michaelis-Menten Equation - D\) Fick\'s Law of Diffusion **Section C: Open-Ended Questions** 11. **Explain how electrical and concentration gradients influence ion movement across the cell membrane.** 12. **What role does oxytocin play during birth in regulating chloride levels and the membrane potential?** 13. **Describe how the Nernst equation is used to calculate the equilibrium potential of an ion. What variables are included in the formula?** **Section D: Matching Questions** Match the following terms with their correct descriptions: +-----------------------------------+-----------------------------------+ | **Term** | **Description** | +===================================+===================================+ | 14\. Na⁺/K⁺ Pump c | A. Moves membrane potential | | | towards Na⁺ equilibrium potential | | | during action potential | +-----------------------------------+-----------------------------------+ | 15\. GABA before birth | B. Depolarizes neurons by | | | allowing Cl⁻ to exit the cell | | b | | +-----------------------------------+-----------------------------------+ | 16\. Resting Potential c | C. Establishes a negative charge | | | inside the cell by pumping Na⁺ | | | out and K⁺ in | +-----------------------------------+-----------------------------------+ | 17\. K⁺ Channels d | D. Hyperpolarizes the membrane, | | | bringing it closer to -100 mV | +-----------------------------------+-----------------------------------+ | 18\. Nernst Equation e | E. Calculates the equilibrium | | | potential of an ion based on | | | concentration gradients | +-----------------------------------+-----------------------------------+ | 19\. GABA after birth f | F. Hyperpolarizes neurons by | | | allowing Cl⁻ to enter the cell | +-----------------------------------+-----------------------------------+ **Section E: Short Answer Questions** 20. **Describe the function of the Na⁺/K⁺ pump and how it sets the resting membrane potential.** 21. **What is the role of potassium in regulating resting membrane potential, and how does a change in extracellular K⁺ concentration affect this?** **Section F: Diagram Interpretation** Refer to a typical **Nernst Equation graph** showing the equilibrium potential of K⁺ at different membrane potentials. 22. **At what membrane potential does K⁺ reach equilibrium, and how does this relate to resting membrane potential in neurons? -100** 23. **Describe how altering extracellular potassium concentration shifts the resting membrane potential in neurons.**