Science, help, a few scientific questions. Help me again

Most of the vigorous leaves are green, and the senescent leaves turn yellow. The green leaves of cochines and maples turn scarlet in autumn, while the leaves of purple duck plantar grass are purple red all year round. They are all leaves, so why are there so many color variations?

It turns out that in addition to green chlorophyll, the leaves also contain orange-yellow carotene and yellow lutein. Typically, chlorophyll is the most abundant, other pigments are less, and the other colors are completely masked by the green color. As a result, the leaves appear green.

However, chlorophyll also has a weakness, that is, it is easy to destroy. In autumn, chlorophyll can't stand the effects of factors such as the temperature dropping day by day. Chlorophyll breaks down and disappears quickly in the leaves, while carotene and lutein are more stable, and they finally "see the light of day" in the fall.

This is the reason why the leaves turn yellow in autumn.

The leaves of cochines and maple trees have another unique ability: when the temperature drops and the chlorophyll decomposes and disappears, the sugar in the leaves is converted into a large number of red anthocyanins, so the leaves turn red. In late autumn, the red leaves all over the mountains are very beautiful.

Ancient poems even praised it as "frost leaves red in February".

As for plants such as purple duck plant, the anthocyanins in the leaves are always dominant, completely covering the color of other pigments, so they are purple-red all year round.

1 uh ......It has nothing to do with the thickness of the cell wall, gases like oxygen and CO2 are freely diffused (there are three forms of diffusion, free diffusion, assisted diffusion, and active transport, of which free diffusion does not require energy and carriers) ......So it doesn't matter how thick the cell wall is. Because these gas molecules are very small, for example, you take a sieve, but if you want to sift through something much smaller than the eye of the sieve......Then you can't sift out no matter how many layers of sieves you make.

2 The substance between the cell wall and the nucleus is called cytoplasm, which is divided into organelles and cell fluid, and to put it bluntly, the "water" in the cell (in fact, it is various liquids) is called the cell fluid (but it does not include the "water" in the nucleus)....Tissue fluid is not easy to interpret ......I think about it, it's like this, there is a circulation in the human body called blood circulation, which you should know, that is, it goes along the blood vessels, then the outside of the blood vessels are cells, right......However, cells do not fit perfectly with each other, so the fluid between cells is called interstitial fluid ......Then the human body has lymphatic vessels in addition to blood vessels, and the fluid in the lymphatic vessels is called lymphatic ......

The relationship between these three is that blood and tissue fluid can be converted into each other, and tissue fluid can be converted into lymphatic fluid.

Glucose is absorbed more quickly in the body.

Sodium chloride: the main component of table salt and stone salt, ionic compounds. Colorless and transparent cubic crystal with a melting point of 801, a boiling point of 1413, and a relative density of . It has a salty taste and is easy to deliquescent when it contains impurities; Soluble in water or glycerol, insoluble in ethanol, insoluble in hydrochloric acid, neutral in aqueous solution.

The solubility in water increases slightly with increasing temperature. When the temperature is lower than , NaCl·2H2O dihydrate can be obtained. Sodium chloride exists in large quantities in seawater and natural salt lakes, which can be used to prepare chlorine, hydrogen, hydrochloric acid, sodium hydroxide, chlorate, hypochlorite, bleaching powder and sodium metal, etc., which is an important chemical raw material; It can be used for food seasoning and pickling of fish, meat and vegetables, as well as for salting soap and tanning leather; Highly refined sodium chloride can be used to make normal saline, which is used in clinical ** and physiological experiments, such as sodium loss, water loss, blood loss, etc.

Sodium chloride can be produced by concentrating crystalline seawater or natural salt lake or salt well water.

Name of Chemical: Sodium Chloride (NaCl).

Chemical Description:

Chemical formula NaCl. Formula. The main ingredient of table salt. Common ones are white cubic crystals or fine crystalline powders. Density gram cm3. Melting Point 801. Boiling point 1413 . Salty. Soluble in water, neutral.

Uses: It can be used for food seasoning and pickling of fish and vegetables; Manufacture of chlorine, hydrogen, hydrochloric acid, sodium hydroxide, chlorate, hypochlorite, bleaching powder, sodium metal, as well as salting out soap and tanning leather. Highly refined NaCl can be used to make saline, for example.

It is widely used in clinical and physiological experiments, such as sodium loss, water loss, blood loss, etc. There are salt deposits in nature, which are abundant in seawater and salt lakes.

Preparation method: It is prepared by crystallization of concentrated seawater, and can also be prepared from natural salt lake or salt well water.

Sodium chloride, the main component of table salt. Experiments that contain more impurities are called coarse salts. Deliquescence due to the presence of impurities such as CaCl2 and MgCl2 in coarse salt. Normal saline in medical care is a sodium chloride solution.

Sodium chloride is easily soluble in water, and the solubility is less affected by temperature changes. The solubility is 36g at 20 degrees Celsius and 40 g at 100 degrees Celsius.

Resources.

The density of this brine is: = = kg m 3 is greater than the required kg m 3 because the density of water is kg m 3 and the brine density is higher than water because of the presence of salt. The density of the saline is too high, and there is too much salt, so water needs to be added.

Suppose x kg of water (volume x dm 3) is added, and it is assumed that the volume of brine after adding water is the sum of the volume of the original brine and the volume of water. Thus, the total mass after adding water is kg, the volume is 5+x dm3 = (5+x)*10 (-3) m 3, and the density is:

x=, i.e. the water that needs to be added.

33.(1) The respiration rate of the fish can be stuffy, and the ability to withstand is related to the quality of the water, and the base is pure.

The respiration rate of the fish can be related to the health status of the fish itself.

3) The higher the temperature of the water, the higher the respiration rate of the fish.