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Why is the plasma membrane more permeable to potassium ions than sodium ions?
Wiki User
∙ 15y ago
Some substances, including sodium and potassium, use a process called active transport to permeate cell walls. Active transport is controlled by other body systems. It limits the quantity of these substances passing through the plasma membrane to match the needs of the body.
Wiki User
∙ 15y ago
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What happens when you open the sodium channels in the membrane of a neuron?
When this occurs, the membranes potenial drops, as potassium and sodium diffuse with their gradient.
Can sodium still enter a membrane if ATP is not present to activate the sodium potassium pump?
no as there is no energy to form a conrormational change in the protein pump
Why Sodium and potassium ion can only cross in axon membrane through protein channel explain why?
At rest sodium in the outside and potassium on the inside as action potential propagate along the axon, depolirization happens and sodium channel opens and allow sodium ions to flood into the neurone. A wave of deporization spread along the neuron, the neuron membrane contain specialised protein called channels. the channel from pore.
What is membrane permeability?
Membrane permeability refers to the ability of molecules, substances, etc. to pass through the membrane. For example, the cell membrane is referred to as 'semi-permeable' because it allows some molecules (such as water) to enter, and stops other molecules (such as sodium ions) from passing through the membrane. If these want to get into the cell, they must then rely on proteins in the cell membrane to let them in.
Which is true of drugs that decrease membrane permeability to sodium ions?
It would decrease the probability of generating a nerve impulse. When a neuron is activiated by a threshold stimulus, the membrane briefly becomes more permeable to sodium. If the permeability is decreased, it will be more difficult for the sodium ions to rush into the cell.
Why is The plasma membrane is much more permeable to K than to Na?
Even when both those atoms are encapsulated with water, potassium is smaller than sodium.
Through the membrane of a resting neuron highly permeable to potassium ions its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is?
Slightly permeable to sodium ions.
When a nerve is activated by a threshold stimulus the membrane becomes more permeable to?
Potassium and Sodium
What regulates which substances enter and leave a cell?
The plasma membrane. Carrier proteins and ion channels are parts of the plasma membrane, and aid in diffusion across concentration gradients, as most things don't freely move from one end of the cell membrane to the other. The Sodium-Potassium pump is a major ion channel in the plasma membrane, and regulates the intake of potassium and export of sodium (3 molecules sodium out, 2 molecules potassium in.)
What are three materials that move through a cell membrane?
Sodium, potassium and calcium are the three things that move through the plasma membrane. There are many other molecules and ions that do move through cell membrane. Plasma membrane have a selective permeable property.
What type of channel does sodium and potassium use to diffuse across the plasma membrane of all cells?
voltage type of channel
Binding of the neurotransmitters with muscle membrane to become permeable to sodium and sodium ions is?
synapses
When is a neurolemma more permeable to potassium than sodium?
during depolarization
Binding of the neurotransmitters with muscle membrane receptors causes the membrane to become permeable to sodium resulting in the influx of sodium ions an what of the membrane?
depolarization
Why can oxygen easily cross the plasma membrane but sodium ions are unable to cross the plasma membrane?
Gh
When hinding of the neurotransmitters with muscle membrane receptors causes the membrane to become permeable to sodium resulting in the influx of sodium ions and what membrane?
action potential of the sarcolemma(the membrane)
Ions used to establish a resting potential?
Potassium and sodium determine the a cell's resting membrane potential. The equilibrium potential (the voltage where no ion would flow) for sodium is about +60 mV while that for potassium is usually around -80 mV, but because the resting cell membrane is approximately 75 times more permeable to potassium than to sodium, the resting potential is closer the the equilibrium potential of potassium. This is because potassium leak channels are always open while sodium come in through voltage gated or ligand gated channels.
