What are the conditions for the separation and restoration of the plasma wall??

The difference between the inside and outside concentration of living cells is zero (either the cell actively transports incoming ions or the external concentration decreases).

First of all, it must be a living plant cell with a cell wall with ** large vacuoles. One case is when the external concentrated solution is a lower concentration of salt solution that can be absorbed by plant cells such as nitrate. The phenomenon is that the precursor wall is separated and then automatically recovers.

In the second case, it is soaked with a sucrose solution of appropriate concentration and then soaked with water (on the specific operation book).

First of all, it must be a living cell with a cell wall. Secondly. There should be a concentration difference. That is, when plasmo-wall separation occurs, the concentration of the external liquid is greater than the concentration of the cell fluid. The concentration of cell fluid is greater than that of the external solution when recovery occurs.

The external solution is less than the intracellular concentration, and if the choice is not 30% sucrose solution, but potassium nitrate solution, the plasma wall will be automatically separated and restored, because potassium ions and nitrate ions are needed by the cell and can penetrate the cell membrane.

Premise: Living plant cells

Separation: The external osmotic pressure is greater than the intracellular osmotic pressure

Restoration: "The Reverse of the Above".

The first is the living cell, the second is that there is a semi-permeable membrane structure, and then the concentration difference between the inside and outside is zero.

Cells are viable and have concentration differences.

Intracellular osmotic pressure > extracellular osmotic pressure.

Live cells. The external concentration is greater than the cell concentration.

The concentration of the external solution in living cells decreases.

happensThe quality god is separated with the wallRequired conditions:

1. Live mature plant cells.

2. There is a semi-permeable membrane.

4. The extracellular fluid is higher than the intracellular fluid.

5. Cell membrane.

Permeability is normal.

Internal and external factors:1. The internal factor is that the elasticity of the protoplasmic layer is greater than that of the cell wall.

stretch and shrinkage.

2. The external cause is that the concentration of cell fluid is less than the concentration of external solution, resulting in cell water loss.

Plasmo-wall separation is a property of living plant cells. When the concentration of the external solution is higher than that of the cell sap, the water of the cytosol will penetrate through the protoplasmic layer and exudate outside the cell.

Plasmo-wall separation occurs <>.

Required conditions:

1. Live mature plant cells are covered with a tape measure.

2. There is a semi-permeable membrane.

4. Extracellular fluid.

higher than intracellular fluid.

5. Cell membrane.

Permeability is normal.

Separation of high walls of the mass scale: the phenomenon of separation of the protoplasmic layer from the cell wall due to the loss of water in the succulent jujube bubble of plant cells.

1. Live mature plant cells.

2. There is a semi-permeable membrane.

4. The extracellular fluid is higher than the inner fluid of the cell.

5. The permeability of the cell membrane is normal.

Plasma wall separation: the phenomenon that the protoplasmic layer is separated from the cell wall due to the loss of water by the vacuoles of plants.

Causes of plasmo-wall separation:

Internal factors: determined by genetic material, plant cells have cell walls; The protoplasmic layer refers to the cytoplasmic membrane, the vacuolar membrane and the cytoplasm between the two, the protoplasmic layer is equivalent to a semi-permeable membrane, and its elasticity is greater than that of the cell wall.

External factors: There is a concentration difference between the inside and outside of the cell. When the concentration of the external solution is greater than the concentration of the cell fluid, the cell loses water and the protoplasts shrink and the plasma wall separates. When placed in clean water, the water absorption swells because the concentration of the external solution is less than the concentration of the cell fluid, and the recovery phenomenon after the separation of the plasma wall appears.

When the concentration of the external solution is greater than the concentration of the cell fluid, the cell loses water, the protoplasts shrink and the plasma wall separates. When placed in clean water, the water absorption is surging because the concentration of the external solution is less than the concentration of the cell fluid, and the recovery phenomenon after the separation of the plasma wall appears.

Plasmo-wall separation restoration refers to the restoration of the protoplasts separated from the plasma wall, that is, the phenomenon of restoring the cellular tension.

Operation: Plasma wall separation and restoration can be seen when the cells that are being separated from the plasma wall are moved to a hypotonic solution or water, or when the plasma wall is separated in a relatively permeable material solution, or when the permeability increases and the semipermeability decreases due to separation, and when the permeability increases after separation. Although permeability can sometimes be measured by using this phenomenon, attention must be paid to the permeability of plasmic-wall separation.

Conditions: The cells to be tested must have a cell wall, large vacuoles. Onion epidermal cells and sucrose solution are generally used. The concentration of the solution should be grasped well, and after the separation of the plasma wall, it should not be left for too long, and it should be restored immediately as much as possible, otherwise the cells will be inactivated.

The centrosome function is different, and the cell will become polyploid.

a. Centrosomes are distributed in animal and lower plant cells, and animal cells cannot be separated from the bioplasm wall, but the lower plant cells can be separated from the plasma wall, and a is wrong;

B. RNA polymerase can catalyze the transcription process, almost all cells contain RNA polymerase, and antidiuretic hormone is synthesized by luminal bucket hypothalamus cells, so hypothalamic cells can synthesize RNA polymerase and antidiuretic hormone, B is correct;

c. The enzyme in lysosomes is a protein, which is synthesized by ribosomes, which needs to be processed by endoplasmic reticulum and Golgi apparatus, and transported through vesicles, C error;

d. Cyanobacteria are prokaryotes and do not have chloroplasts, d is wrong

Therefore, d

1.judging the life and death of plant cells;

2.Measure the concentration of cell fluid;

3.Observe the cell membrane and cell wall;

4.It proves that the cell wall and the cell membrane can be separated, and the role of the cell wall is to support and protect, and further understand the structure of the cell;

5.This lays the foundation for cell fusion, and only by removing the cell wall can we achieve better fusion of cells. It provides theoretical support for genetic breeding and cell hybridization.

6.It provides support for the metabolic mode of cells, such as the dialysis effect of cell membranes.

The phenomenon of plant cells separating the protoplasmic layer from the cell wall due to the loss of water in vacuoles is called plasma wall separation. Spine.

Plasmo-wall separation is a property of living plant cells. When the concentration of the external solution is higher than the concentration of the cell fluid, the water of the cell fluid will penetrate through the protopplasm layer to the outside of the cell, and the volume of the vacuole will shrink, because the elasticity of the cell wall is limited, and the elasticity of the protoplast is larger, so after the cell wall stops shrinking, the protoplast continues to contract, so that the cell membrane and the cell wall will gradually separate, and the space between the protoplast and the cell wall is filled with a solution with a higher concentration of the outside.

Conditions required for plasmo-wall separation: live mature plant cells, semi-permeable membranes, extracellular fluid higher than intracellular fluid, and normal permeability of cell membranes.

When a well-developed vacuole plant cell is immersed in a hypertonic solution, the protoplasm shrinks and separates from the cell wall, a phenomenon called plasma wall separation. Due to the semi-permeability of the cell membrane and the cell membrane, the cell fluid is dehydrated in the hypertonic fluid and the turgor pressure decreases, and soon the critical state of plasma wall separation is present (the turgor pressure is 0 at this time).

If further dehydration, the protoplast shrinks and separates from the cell wall, and when the osmotic pressure of the cell fluid is equal to that of the outer fluid, the contraction stops. The solution used in this case is called the plasmo-wall separator. As a separation, the cell membrane must be semi-permeable to its solutes, and non-electrolytes with large molecular weights (e.g., sugars) or highly soluble neutral salts are often used as separation fluids.

If Ca ions with strong adsorption to cell membrane and cell wall are used as the separation solution, the entire protoplast contour is concave inward, resulting in the separation of the concave plasma wall.

If K and Na with weak adsorption are used as the separation solution, the convex plasma wall separation occurs when the cells are immersed in the separation solution, and the concave part weakens with the passage of time, and finally the whole protoplast presents a convex separation state, and the time required to this point is called the plasma separation time.

Procedure steps for plasmo-wall separation:

Temporary film production: Selection: The outer skin of the onion is particularly dark in purple; Description:

Before the experiment, it is best to soak the onion in water, which can make the onion absorb more water, and the metabolism is relatively vigorous, and the experimental effect is obvious. Peel off the outer layer of the onion in two layers, as the outermost one may have died.

Take the epidermis: on the outer skin of the onion, use a blade to draw the word "well", and gently tear a small piece with tweezers; Key: It is best to tear off a single layer of cells, if it is too thick, it will make the cells overlap, which will seriously affect the experimental effect

Drop a drop of water on the glass slide**, and then put the removed onion skin in the water, flat; Add a coverslip.

Note that the skin of the onion should not be curled up and should not have bubbles; When adding the coverslip, the hand is lowered at an angle of about 45° from one side and filled with clean water between the slide and the coverslip in order to squeeze out the air.