Ch%2013%20ss.pdf

1. The RMP does not change when gated ion channels open. 2. Sodium ions diffuse into the cell through membrane channels. 3. Translation at ribosomes is required for the formation of proteins found within all membrane channels and carriers. 4. Voltage-gated channels are not found in all types of cells. 5. Reduced chlorine atoms can diffuse into a cell through specific channels. 6. If an injection of potassium caused the [K+] in the ECF to exceed that of the cytosol, depolarization would occur. 7. An impulse involves APs appearing to move as a wave of depolarization followed by a “wave of repolarization” on a membrane. 8. Unequal diffusion of Na+ and K+ contributes to the development of an RMP. 9. Ions are moving through a cell membrane even during the resting potential. 10. Chloride ions diffusing through a plasma membrane would increase the membrane potential. 11. The pumping of chloride ions through a plasma membrane would tend to decrease the membrane potential. 12. The entire cytosol is not negatively charged compared to the entire ECF. 13. Hyperpolarizing a cell that has a RMP of -70 mV will result in the cell’s membrane potential becoming more negative. 14. Calcium diffusing into a cell during the resting potential would decrease membrane potential. 15. Holding a perfume nozzle down would be similar to a depolarization at a specific membrane site during an action potential. 16. Depolarization does not affect a cell’s resting membrane potential. 17. When a membrane potential is moving away from the RMP, it can be a depolarization or a hyperpolarization. 18. Resting potentials are always negative. 19. Sodium-potassium pump activity helps contribute to a cell’s membrane potential. 20. The RMP represents an electrical gradient across a membrane. 21. One action potential at point X on a membrane is not an impulse. 22. Membrane voltage during action potential crosses zero twice 23. A hair cannot experience an action potential. 24. If a cell’s RMP is -70 mV, then that RMP is less than the cell’s potential when the cell is hyperpolarized. 25. Neurons and muscle cells have voltage-gated calcium channels 26. Opening a mechanically gated sodium channel in a hair root plexus may or may not initiate an action potential. 27. Leak channels consist of polypeptides. 28. Nucleotides are required for the formation of carriers and channels in a cell membrane. 29. Movement of ions through voltage-gated channels is always passive. 30. Afferent and efferent impulses in the nervous system’s feedback loops involve opening and closing of voltage-gated channels. 31. Leak channels do not have gates. 32. Ions can move from higher concentration to lower concentration through membrane carriers and channels. 33. Action potentials occur along neuron axons within the epidermis. 34. A graded potential can occur in response to the opening of ligand-gated sodium channels. 35. During a graded potential, the resting membrane potential is still considered to be unchanged. 36. Opening a mechanically gated channel could result in a decrease in membrane potential. 37. Ions pass through leak channels constantly. 38. Ligand-gated channels cannot perform facilitated diffusion but can allow simple diffusion through a membrane. 39. An impulse could be identified on a graph showing electrical changes on a membrane. 40. A neuron or muscle would not be able to make voltage-gated channels if these cells lacked linear DNA. 41. Hyperpolarization can result without the movement of anions through the plasma membrane. 42. Not all living cells experience periodic reversals of membrane polarity. 43. Oxidized sodium atoms can diffuse into a cell through channels. 44. Establishing a RMP involves more diffusion of potassium out of the cell and less diffusion of sodium into the cell. 45. When sodium ions are pumped through a plasma membrane, the membrane potential tends to increase. 46. Action potentials are required for a person to experience cutis anserina. 47. A membrane potential of -70 mV is lower than a membrane potential of -80 mV. 48. Na+/K+ pumps contribute to the development of an RMP. 49. Repolarization from a depolarized state involves an increase in membrane potential. 50. A graded potential can occur in response to the opening of ligand-gated potassium channels. 51. It takes more than one action potential on a membrane to be considered an impulse. 52. Threshold voltage could be labeled on a graph showing electrical changes on a membrane. 53. Graded potentials do not involve the cell membrane’s potential reaching zero. 54. The refractory period could be identified on a graph showing electrical changes on a membrane.

55. More Cl- diffusion through channels would cause hyperpolarization 56. Pumping potassium ions through a plasma membrane promotes an increase in membrane potential. 57. The components of membrane channels and carriers are not synthesized at the cell membrane. 58. Graded potentials can be a depolarization or a hyperpolarization. 59. Opening a ligand-gated calcium channel during the resting potential would decrease the membrane’s potential. 60. Threshold voltage is relevant only to voltage-gated channels. 61. In order to reach threshold from the RMP, a membrane potential must decrease. 62. Calcium ions are pumped out of the cell via active transport. 63. Resting potentials develop mainly because of unequal diffusion and unequal pumping of ions. 64. The RMP could be labeled on a graph showing electrical changes on a membrane. 65. An impulse requires voltage-gated channels. 66. Adipocytes do not conduct impulses. 67. Voltage-gated potassium channels make the inside border of a membrane become negative near the end of an action potential. 68. After hyperpolarization, a membrane must depolarize in order to reach RMP. 69. Hyperpolarizations do not lead to action potentials. 70. An action potential may be initiated at a Meissner’s corpuscle. 71. Primary active transport is necessary to maintain concentration gradients for Na+, K+, Ca2+, and Cl- ions. 72. Opening Ca2+ channels during the RMP causes the inside border of the membrane to become less negative. 73. Concentration and electrical gradients both affect the movement of ions. 74. More K+ diffusion through gated channels would tend to increase a cell’s membrane potential. 75. Normally, calcium ion diffusion through a membrane channel has a negative effect on the magnitude of a membrane potential. 76. Anions tend to move toward positively charged regions. 77. Depolarization is a decrease in membrane potential. 78. Letting a perfume bottle nozzle pop up after a spray is like a membrane site repolarizing at the end of an action potential. 79. Diffusion through voltage-gated K+ channels could be identified on a graph showing electrical changes on a membrane. 80. Impulses involve action potentials occurring along different sites on a cell membrane. 81. Movement toward threshold voltage from a depolarized condition does not always involve repolarization. 82. All living cells have a membrane potential. 83. Ions move from higher concentration to lower concentration through membrane channels. 84. A region of the membrane is unresponsive to another stimulus while that region is in the refractory period. 85. It is not possible for a neuron or muscle cell to experience repeated action potentials without periods of repolarization. 86. A graded potential may initiate an action potential in a neuron or muscle cell. 87. A membrane potential is a difference in electrical charge between two different sites. 88. Opening a ligand-gated chloride channel during the resting potential would cause the membrane potential to increase. 89. A refractory period is associated with action potentials but not graded potentials. 90. Axon terminals have voltage-gated sodium channels 91. The refractory period is a phenomenon associated with voltage-gated channels in muscle cells and neurons. 92. There is always a difference in electrical charge between the inside and outside border of a membrane during a graded potential. 93. Only muscle cells and neurons have voltage-gated channels. 94. Osteocytes and chondrocytes can experience graded potentials. 95. When diffusing, cations and anions move down their own concentration gradients. 96. More Ca2+ diffusion through gated channels would tend to decrease a cell’s membrane potential. 97. Membrane potentials result, in part, from an unequal diffusion of cations through the cell membrane. 98. Action potentials are the result of ion movement through voltage-gated channels. 99. Ion diffusion through any type of channel would not change the RMP 100. Carriers and channels in the cell membrane do not contain nucleotides. 101. The inside (fatty acid region) of a plasma membrane is not charged. 102. A membrane potential develops partly because cell membranes are "leakier" to potassium ions than to sodium ions. 103. Cations tend to move toward negatively charged regions. 104. Voltage-gated channel proteins are coded for by genes in linear DNA. 105. Chloride ions are pumped out of the cell by carriers in the cell membrane. 106. All living cells have membrane potentials 107. Threshold voltage in an excitable cell is less than the RMP, 108. Sodium-potassium pumps consist of polymers containing peptide bonds.

- This statement is true. If the extracellular concentration of potassium ([K+]) exceeds that of the cytosol, it can disrupt the normal ionic balance, leading to depolarization. This is because the resting membrane potential is maintained by a higher concentration of K+ inside the cell compared to the extracellular fluid. 7. An impulse involves APs appearing to move as a wave of depolarization followed by a "wave of repolarization" on a membrane. - This statement is true. An impulse, such as an action potential (AP), often appears as a wave of depolarization followed by a wave of repolarization as it propagates along a cell membrane. This is characteristic of the events during an action potential. 8. Unequal diffusion of Na+ and K+ contributes to the development of an RMP. - This statement is true. The unequal diffusion of sodium (Na+) and potassium (K+) ions, along with the activity of the sodium-potassium pump, contributes to the establishment of the Resting Membrane Potential (RMP). The higher permeability of the membrane to K+ and the lower permeability to Na+ play a significant role in setting the RMP. 9. Ions are moving through a cell membrane even during the resting potential. - This statement is true. Ions are constantly moving through the cell membrane, even during the resting potential. This movement is primarily due to the presence of leak channels that allow the passive diffusion of ions. 10. Chloride ions diffusing through a plasma membrane would increase the membrane potential. - This statement is false. Chloride ions (Cl-) are negatively charged, and their diffusion into the cell would typically lead to hyperpolarization, not an increase in the membrane potential. 11. The pumping of chloride ions through a plasma membrane would tend to decrease the membrane potential. - This statement is true. The active transport of chloride ions out of the cell would tend to decrease the membrane potential, as it moves negative ions out of the cell. 12. The entire cytosol is not negatively charged compared to the entire ECF. - This statement is true. The entire cytosol is not necessarily negatively charged compared to the entire Extracellular Fluid (ECF). The resting membrane potential is typically a small negative value, but it's not extremely negative. The potential difference arises from the relative concentrations and permeabilities of various ions. 13. Hyperpolarizing a cell that has a RMP of -70 mV will result in the cell’s membrane potential becoming more negative. True. Hyperpolarization makes the cell's membrane potential more negative. This occurs when the cell becomes more permeable to potassium ions, which are negatively charged, causing the membrane potential to move further away from the resting membrane potential (RMP).

14. Calcium diffusing into a cell during the resting potential would decrease membrane potential. True. Calcium ions have a positive charge, so when they diffuse into a cell, they increase the positive charge inside the cell, making the membrane potential less negative. This would decrease the membrane potential. 15. Holding a perfume nozzle down would be similar to a depolarization at a specific membrane site during an action potential. True. When you hold a perfume nozzle down, you release a burst of fragrance, similar to depolarization during an action potential where there is a sudden increase in membrane potential at a specific site. 16. Depolarization does not affect a cell’s resting membrane potential. False. Depolarization is a process that involves the membrane potential becoming less negative. If a cell undergoes depolarization, it moves away from the resting membrane potential. 17. When a membrane potential is moving away from the RMP, it can be a depolarization or a hyperpolarization. True. If the membrane potential becomes less negative than the resting membrane potential, it is a depolarization. If it becomes more negative, it is a hyperpolarization. 18. Resting potentials are always negative. True. Resting membrane potentials are typically negative, meaning the inside of the cell is more negative compared to the outside. 19. Sodium-potassium pump activity helps contribute to a cell’s membrane potential. True. The sodium-potassium pump helps maintain the resting membrane potential by actively pumping sodium out of the cell and potassium into the cell, which contributes to the electrical gradient across the membrane. 20. The RMP represents an electrical gradient across a membrane. True. The resting membrane potential represents an electrical gradient where there is a difference in electrical charge between the inside and outside of the cell membrane. 21. One action potential at point X on a membrane is not an impulse. - An impulse typically refers to the transmission of a signal along a nerve or muscle cell, which involves multiple action potentials traveling down the length of the cell. A single action potential at a specific point on the membrane is just a brief electrical event, not a complete impulse. 22. Membrane voltage during action potential crosses zero twice. - During an action potential, the membrane voltage does indeed cross zero twice. The first zero-crossing represents depolarization (when the membrane potential becomes positive) and the second zero-crossing represents repolarization (when the membrane potential returns to its resting state, which is typically negative).

31. Leak channels do not have gates. - Leak channels do not have gates that open or close in response to specific stimuli. They are typically open all the time, allowing a slow leak of ions across the membrane. 32. Ions can move from higher concentration to lower concentration through membrane carriers and channels. - This statement is true. Ions can move from areas of higher concentration to lower concentration through passive transport processes via channels or carriers in the membrane. 33. Action potentials occur along neuron axons within the epidermis. - Action potentials primarily occur in nerve cells (neurons) and not in the epidermis, which is the outermost layer of the skin. Neurons transmit action potentials, but the epidermis is not directly involved in generating them. 34. A graded potential can occur in response to the opening of ligand-gated sodium channels. - True: Graded potentials can result from the opening of ligand-gated sodium channels because these channels allow the entry of sodium ions, which can depolarize the membrane locally, leading to a graded potential. 35. During a graded potential, the resting membrane potential is still considered to be unchanged. - True: Graded potentials are localized changes in membrane potential, and they do not affect the overall resting membrane potential of the cell. The rest of the membrane retains its resting potential. 36. Opening a mechanically gated channel could result in a decrease in membrane potential. - True: Mechanically gated channels can allow the movement of ions across the membrane. If these channels allow the efflux of positively charged ions or the influx of negatively charged ions, the result can be a decrease in membrane potential (hyperpolarization). 37. Ions pass through leak channels constantly. - True: Leak channels are always open and allow a constant, passive movement of ions across the membrane, helping to maintain the resting membrane potential. 38. Ligand-gated channels cannot perform facilitated diffusion but can allow simple diffusion through a membrane. - True: Ligand-gated channels open in response to specific chemical signals (ligands) and allow the passive movement of ions down their concentration gradients, which is a form of simple diffusion. Facilitated diffusion usually involves carrier proteins. 39. An impulse could be identified on a graph showing electrical changes on a membrane. - True: An impulse, such as an action potential, is a distinct change in the membrane potential, and it can be identified on a graph showing electrical changes over time.

40. A neuron or muscle would not be able to make voltage-gated channels if these cells lacked linear DNA. - False: Voltage-gated channels are proteins, and their production is controlled by the cell's genetic information. Linear DNA contains the genetic code necessary for synthesizing these channels. 41. Hyperpolarization can result without the movement of anions through the plasma membrane. - True: Hyperpolarization can occur if the membrane becomes more negative (for example, through the efflux of positively charged ions like potassium) without the need for anions to move. 42. Not all living cells experience periodic reversals of membrane polarity. - True: Some cells, like neurons, experience periodic reversals of membrane polarity during action potentials. However, not all cell types go through this process. 43. Oxidized sodium atoms can diffuse into a cell through channels. - False: Sodium channels typically allow the passage of sodium ions (Na+), not oxidized sodium atoms. 44. Establishing a RMP involves more diffusion of potassium out of the cell and less diffusion of sodium into the cell. - True: The resting membrane potential is mainly established by the passive diffusion of potassium ions out of the cell, which makes the inside more negative, and the limited influx of sodium ions. 45. When sodium ions are pumped through a plasma membrane, the membrane potential tends to increase. - True: Sodium-potassium pumps actively transport sodium ions out of the cell, which contributes to maintaining the resting membrane potential. This process helps to stabilize or increase the membrane potential. 46. Action potentials are required for a person to experience cutis anserina. - False: Cutis anserina, commonly known as "goosebumps," is a response of the skin's hair follicles to various stimuli. It does not directly involve action potentials in neurons. 47. A membrane potential of -70 mV is lower than a membrane potential of -80 mV. - False: A membrane potential of -70 mV is higher than a membrane potential of -80 mV. Membrane potential is a measure of electrical charge, and more negative values indicate a lower potential. 48. Na+/K+ pumps contribute to the development of an RMP. - True: Sodium-potassium pumps play a crucial role in maintaining the resting membrane potential by actively transporting sodium ions out of the cell and potassium ions into the cell.

57. The components of membrane channels and carriers are not synthesized at the cell membrane. - True: Membrane channels and carriers are typically proteins, and their components, including the actual protein molecules, are synthesized within the cell and then transported to the cell membrane. 58. Graded potentials can be a depolarization or a hyperpolarization. - True: Graded potentials can be either depolarizations (making the membrane potential more positive) or hyperpolarizations (making it more negative) depending on the specific ion movements through the membrane. 59. Opening a ligand-gated calcium channel during the resting potential would decrease the membrane’s potential. - True: Opening a ligand-gated calcium channel during the resting potential can result in an influx of calcium ions, which are positively charged, and this would tend to depolarize the membrane. 60. Threshold voltage is relevant only to voltage-gated channels. - True: Threshold voltage is a concept primarily associated with voltage-gated channels, particularly in excitable cells like neurons and muscle cells. It represents the membrane potential at which these channels are more likely to open. 61. In order to reach threshold from the RMP, a membrane potential must decrease. - False: In most cases, reaching the threshold from the resting membrane potential involves an increase in membrane potential. The threshold is the point at which the membrane becomes more excitable and is more likely to depolarize further, leading to an action potential. 62. Calcium ions are pumped out of the cell via active transport. - True: Calcium ions are typically pumped out of the cell by active transport processes to maintain proper intracellular calcium levels. 63. Resting potentials develop mainly because of unequal diffusion and unequal pumping of ions. - True: The resting membrane potential is primarily established by the unequal diffusion of ions, with potassium ions playing a significant role in this process, as well as the active transport of ions like sodium and potassium. 64. The RMP could be labeled on a graph showing electrical changes on a membrane. - True: The resting membrane potential (RMP) is a specific, stable value that can be represented on a graph showing electrical changes on a membrane as a horizontal line at a certain voltage. 65. An impulse requires voltage-gated channels.

- True: The initiation and propagation of impulses, such as action potentials, typically involve voltage-gated channels in excitable cells. 66. Adipocytes do not conduct impulses. - True: Adipocytes (fat cells) are not excitable cells like neurons and muscle cells, so they do not conduct impulses or generate action potentials. 67. Voltage-gated potassium channels make the inside border of a membrane become negative near the end of an action potential. - True: Voltage-gated potassium channels play a crucial role in repolarizing the membrane during an action potential, making the inside more negative. 68. After hyperpolarization, a membrane must depolarize in order to reach RMP. - True: After hyperpolarization, the membrane potential is more negative than the resting membrane potential. To return to the resting potential, the membrane must depolarize. 69. Hyperpolarizations do not lead to action potentials. - True: Hyperpolarizations make the membrane potential more negative, which generally inhibits the initiation of action potentials. Action potentials are typically initiated from a depolarized state. 70. An action potential may be initiated at a Meissner’s corpuscle. - False: Meissner's corpuscles are sensory receptors responsible for detecting touch and pressure but do not initiate action potentials. Action potentials are initiated in excitable cells like neurons. 71. Primary active transport is necessary to maintain concentration gradients for Na+, K+, Ca2+, and Cl- ions. - True: Primary active transport, typically performed by ion pumps like the sodium-potassium pump, is essential for maintaining concentration gradients of various ions across the cell membrane. 72. Opening Ca2+ channels during the RMP causes the inside border of the membrane to become less negative. - True: Opening calcium (Ca2+) channels during the resting membrane potential can result in the influx of positively charged calcium ions, making the inside of the cell less negative (depolarization). 73. Concentration and electrical gradients both affect the movement of ions. - True: The movement of ions across the cell membrane is influenced by both concentration gradients (driven by differences in ion concentrations) and electrical gradients (driven by differences in electrical charge).

- True: All living cells, to some extent, have a membrane potential due to the selective permeability of their cell membranes to various ions. 83. Ions move from higher concentration to lower concentration through membrane channels. - True: Ions generally move through membrane channels from areas of higher concentration to areas of lower concentration as they follow their concentration gradients. 84. A region of the membrane is unresponsive to another stimulus while that region is in the refractory period. - True: During the refractory period, a region of the membrane is less responsive to additional stimuli, which is a key feature of this phenomenon. 85. It is not possible for a neuron or muscle cell to experience repeated action potentials without periods of repolarization. - True: Repolarization is essential for the recovery of a cell's membrane potential and its ability to generate subsequent action potentials. Without repolarization, sustained firing of action potentials would not be possible. 86. A graded potential may initiate an action potential in a neuron or muscle cell. - True: Graded potentials can serve as the initial triggers for action potentials in excitable cells, as they may bring the membrane potential closer to the threshold for generating an action potential. 87. A membrane potential is a difference in electrical charge between two different sites. - True: A membrane potential represents a difference in electrical charge between the inside and outside of a cell or a cellular structure. 88. Opening a ligand-gated chloride channel during the resting potential would cause the membrane potential to increase. - False: Opening a ligand-gated chloride channel during the resting potential would typically lead to the influx of negatively charged chloride ions and cause hyperpolarization, making the membrane potential more negative. 89. A refractory period is associated with action potentials but not graded potentials. - True: The refractory period is a characteristic of action potentials, and it does not typically apply to graded potentials. 90. Axon terminals have voltage-gated sodium channels. - True: Axon terminals of neurons can have voltage-gated sodium channels, which play a role in the generation of action potentials for signal transmission. 91. The refractory period is a phenomenon associated with voltage-gated channels in muscle cells and neurons.

- True: The refractory period is primarily associated with voltage-gated channels in excitable cells like muscle cells and neurons. 92. There is always a difference in electrical charge between the inside and outside border of a membrane during a graded potential. - True: Graded potentials represent localized differences in electrical charge between the inside and outside of the cell membrane, which can result from ion movement. 93. Only muscle cells and neurons have voltage-gated channels. - False: While voltage-gated channels are most commonly associated with muscle cells and neurons, they can also be found in other excitable cell types. 94. Osteocytes and chondrocytes can experience graded potentials. - True: Osteocytes (bone cells) and chondrocytes (cartilage cells) are not typically excitable cells like neurons or muscle cells, but they can experience graded potentials in response to certain stimuli. 95. When diffusing, cations and anions move down their own concentration gradients. - True: Both cations and anions move down their respective concentration gradients when they diffuse through ion channels. 96. More Ca2+ diffusion through gated channels would tend to decrease a cell’s membrane potential. - True: Calcium ions (Ca2+) are positively charged, and their influx through gated channels would tend to depolarize the cell, making the membrane potential less negative. 97. Membrane potentials result, in part, from an unequal diffusion of cations through the cell membrane. - True: Membrane potentials are influenced by the unequal diffusion of ions, particularly cations like sodium (Na+) and potassium (K+), through the cell membrane. 98. Action potentials are the result of ion movement through voltage-gated channels. - True: Action potentials are initiated and propagated by the sequential opening and closing of voltage-gated ion channels, which allow the movement of ions across the membrane. 99. Ion diffusion through any type of channel would not change the RMP. - False: Ion diffusion through channels, particularly leak channels, plays a significant role in maintaining and influencing the resting membrane potential. 100. Carriers and channels in the cell membrane do not contain nucleotides. - True: Carriers and channels in the cell membrane are primarily composed of proteins and lipids. They do not contain nucleotides, which are components of DNA and RNA. 101. The inside (fatty acid region) of a plasma membrane is not charged.

Certainly, I'll continue explaining the remaining statements: 108. **Sodium-potassium pumps consist of polymers containing peptide bonds.** - False: Sodium-potassium pumps, also known as sodium-potassium ATPases, are not polymers containing peptide bonds. They are integral membrane proteins made up of several subunits but do not form polymers. These pumps play a crucial role in maintaining the electrochemical gradients of sodium and potassium ions across the cell membrane. 109. **Linear DNA is not directly involved in the synthesis of proteins that comprise membrane channels and carriers.** - False: Linear DNA contains the genetic code for the synthesis of all proteins in the cell, including those that comprise membrane channels and carriers. Linear DNA serves as the template for the transcription of mRNA, which, in turn, is translated into proteins by ribosomes. 110. **At the peak of an action potential, the outer border of the membrane is more negative than the inner border.** - False: At the peak of an action potential, the inner border of the membrane (the side facing the cytoplasm) is more positive, while the outer border (the side facing the extracellular space) is more negative. This reversal of membrane potential is a characteristic feature of an action potential. 111. **Unequal pumping of two major ions results, in part, in the establishment of a membrane potential.** - True: Unequal pumping of ions, such as the active transport of sodium and potassium ions by the sodium-potassium pump, plays a significant role in establishing and maintaining the membrane potential. This asymmetrical ion transport contributes to the separation of charges across the membrane. 112. **Keratinocytes do not experience action potentials.** - True: Keratinocytes, which are the primary cell type in the epidermis (the outermost layer of the skin), do not typically experience action potentials. Action potentials are primarily associated with excitable cells like neurons and muscle cells. 113. **During an action potential, there are two moments when the membrane potential is zero.** - True: During an action potential, the membrane potential briefly crosses zero as it depolarizes (becomes more positive) at the onset of the action potential and later repolarizes (returns to the resting state), briefly passing through zero again. 114. **The building blocks linked together at ribosomes to make channel and carrier proteins are not synthesized at the ribosomes.** - False: Ribosomes are responsible for synthesizing proteins, including channel and carrier proteins, by linking together amino acids, which are the building blocks of proteins.

115. **Ligand-gated K+ channels are not responsible for bringing the membrane potential back to RMP after the membrane potential.** - False: Ligand-gated K+ channels, often activated by specific signaling molecules (ligands), can contribute to the restoration of the membrane potential back to the resting state after depolarization. 116. **Initiation of an impulse requires an initial decrease in membrane potential.** - False: The initiation of an impulse, such as an action potential in a neuron, typically requires an initial increase in membrane potential to reach the threshold for firing. 117. **The establishment of an RMP involves more diffusion of potassium out of the cell and more pumping of sodium out of the cell.** - True: The resting membrane potential (RMP) is established by the balance between passive diffusion (mainly potassium efflux) and active transport (sodium-potassium pump) of ions across the cell membrane. 118. **Changing a membrane's potential from -80 mV to -90 mV is increasing the potential.** - False: Changing the membrane potential from -80 mV to -90 mV represents a decrease in membrane potential, making it more negative. 119. **An impulse can be initiated without involving the opening of ligand-gated or mechanically gated channels.** - True: Impulses, such as action potentials in neurons, can be initiated without the direct involvement of ligand-gated or mechanically gated channels. They are typically initiated by reaching the threshold voltage through other means, such as voltage-gated channels or pacemaker cells. If you have any more questions or need further clarification on any of these statements, feel free to ask.