Intracellular potassium efflux Sodium influx What is the mode of transport

The mode of transportation is active transportation.

Sodium-potassium pumps. sodium-potassium PMP).

A special protein present in the cell membrane can break down ATP to obtain energy, and use this energy for Na, K.

The main role of ATPase is to control the concentration difference between K and Na ions inside and outside the cell membrane and maintain the osmotic pressure of the intracellular fluid.

When nerve cells are at rest, there are a large number of sodium ions outside the cell, and the concentration of potassium ions in the cell is higher than that outside the cell, so the transport mode of potassium ion outflow and sodium ion inflow is assisted diffusion.

Knowledge Focus] Assisted diffusion concept explained: Assisted diffusion is one of the ways in which substances enter and exit cells through the plasma membrane. The substance must be assisted by a carrier protein in order to diffuse from the high-concentration side through the plasma membrane to the low-concentration side, but this method does not consume metabolic energy.

For example, the entry of glucose into tissue cells, as well as the sodium and potassium ions in this question from the high concentration side to the low concentration side, are typical assisted diffusion.

Confusing concepts] Free diffusion, active transport, passive transport, etc., please be sure to pay attention to the distinction.

Sodium influx and potassium efflux are passive transports. Both potassium outflow and sodium influx follow the concentration gradient and belong to the passive transport mode. Passive transport refers to the transmembrane transport of substances from high to low concentrations through simple diffusion or assisted diffusion.

The power for transport comes from the concentration gradient inside and outside the membrane and does not need to consume the cell's energy.

Preparation method:

The chemical properties of sodium are reactive. It is easily oxidized in the air to produce sodium oxide, which emits a yellow flame when burned. It reacts with water to generate sodium hydroxide, and reacts with alcohol to form sodium alkoxide.

Therefore, it is usually kept in kerosene. Sodium reacts with most elements, but it is difficult to react with boron, carbon, iron, and nickel. Sodium can react with silicates at high temperatures and attack glass and porcelain.

The main preparation methods of sodium are the Dangsi method and the Kasner method. Calcium chloride is added to the table salt, heated by electrolytic bath at a temperature of 500 degrees and a voltage of 6V, and sodium metal is generated at the cathode and chlorine is generated at the anode by electrolysis. It is then purified and molded and packaged with liquid paraffin.

The Cassna method uses sodium hydroxide as raw material, puts it into an iron container, melts at a temperature of 320 to 330 degrees, uses nickel as the anode and iron as the cathode, sets a nickel mesh separator between the electrodes, and the electrolysis voltage is 4 to 4.5V, and the cathode precipitates metal sodium and releases hydrogen.

Analysis: At resting potential, potassium ion channels are opened, and potassium ions flow out (from high to low concentrations), which is an assisted diffusion.

2.At the action potential, the dry channel of sodium ions is opened, and the sodium ions flow inward (from high to low concentrations), which is also an assisted diffusion.

1) Resting potential potassium ion outflow to assist in diffusion, requires carrier proteins, along the concentration gradient.

2) In order to assist in diffusion, the influx of nano ions at the action potential requires a carrier egg to open the argument and follow the concentration gradient.

3) The outflow of sodium ions from the cavity next to the shed and the influx of potassium ions in the recovery potential are both active transport and reverse concentration gradient.

Active transportation.

At resting potential, the concentration of potassium ions outside the cell membrane is high, so the potassium outflow is active transport. Under normal physiological conditions, the concentration of K+ in human erythrocytes is equivalent to 30 times that of plasma, but K+ can still enter erythrocytes from plasma, and the concentration of Na+ is much lower than that in plasma, but Na+ is still permeable from erythrocytes to plasma, showing an inverse concentration gradient of "uphill" transportation.

The effects of potassium ions in the human body are:

To maintain the role of neuromuscular excitability, only when potassium ions are within the normal range, the neuromuscular junction of the human body can play a normal role and maintain normal neuromuscular activity. If the concentration of potassium ions is too high or too low, it is easy to have weakness and weakness in the limbs.

Potassium ions play an important role in the normal activities of the myocardium, potassium ions are within the normal range, the electrophysiological activities of the myocardium can maintain normal function, if the concentration of potassium ions is too low, the conduction system of the myocardium will slow down, if the concentration of potassium ions is too high, there will be rapid cardia, cardiac arrest.

Potassium plays an important role in maintaining the normal function of the nervous system, and patients with low potassium levels may experience symptoms of lack of energy, indifference and disinterest in everything.

The way sodium and potassium ions move in and out of cells is active transport.

In fact, it is Na+-K+ATPase, which is generally considered to be a tetramer composed of 2 large subunits and 2 small subunits. Na+-K+ ATPase undergoes a conformational change through phosphorylation and dephosphorylation processes, resulting in a change in affinity for Na+ and K+.

On the inner side of the membrane, Na+ binds to the enzyme, activates the activity of ATPase, decomposes ATP, the enzyme is phosphorylated, and the conformation changes, so the binding site to Na+ turns to the outside of the membrane. This phosphorylated enzyme has a low affinity for Na+ and a high affinity for K+, thus releasing Na+ on the outside of the membrane and binding to K+.

For example, animal cells often transport H+ through Na+ H+ reverse synergistic transport to regulate the pH value in the cell, that is, the entry of Na+ into the intracellular accompaniment of H+ is excreted by H+. In addition, the proton pump can directly use ATP to transport H+ to regulate the pH of the cells.

Another mechanism is Na+-driven Cl--HCO3- exchange, i.e., the entry of Na+ with HCO3- is accompanied by the efflux of Cl- and H+, as in the case of band-3 proteins on erythrocyte membranes.

Sodium ions are actively transported, potassium ions are assisted in diffusion, and the channel is through sodium and potassium bang (the word cannot be typed by mobile phones), but this is a supplementary content, and it is not required by the college entrance examination.

Dream of the weeping moon is the correct solution Human anatomy and physiology (People's Medical Publishing House) said so.

For the college entrance examination, it is true that it is not required, but you must understand.

Influx of sodium ions at action potential: assists in diffusion.

Sodium efflux upon recovery of resting potential: active transport.

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Sodium influx assists in diffusion Potassium outflow assists.

On the one hand, it is said that sodium ions are used to assist diffusion, and on the other hand, it is said that it is actively transported, so I can't tell what it is. _?

For example, the formation of resting potential is caused by K+ efflux, and the action potential is caused by Na+ influx, and the concentration gradient requires the assistance of carrier proteins, all of which are assisted diffusion in passive transport (including free diffusion and assisted diffusion).

Active and passive operation of transportation. Freedom is not free to spread, because both types of activities are power-based. There are heavyweights. In addition, when heated, it will adhere more easily. Both of these properties attach secretively from the hair cell glands.

I have learned about channels (passive transport) and ion pumps (active transport). Channels such as potassium channels at resting potential, sodium channels during depolarization (many neurons are channels). Ion pumps, for example, have sodium-potassium pumps, which pump 3 sodium extracellularly and 2 potassium intracellularly.

All belong to active transport, which refers to the process of transporting substances into or out of the cell membrane under the action of energy with the assistance of the carrier against the concentration gradient.

Both assisted proliferation and active transport are available.